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RE49883 | DETAILED DESCRIPTION A hot water system provides hot water to the hot water distribution pipes of a building. The quantity of hot water used by the building can vary by time of day, season, various types of machine cycles, etc. One problem is to regulate the temperature of the hot water supplied to the hot water pipes over varying loads. Short time frame changes in loads (e.g. minutes) can be particularly troublesome. For example, where a hot water heater's controls have ramped up to provide relatively high hot water flow rates, while maintaining the desired hot water temperature, if the flow rate should suddenly drop (e.g. one or more machine cycles stop using hot water), there can be an undesired period of time, during which the hot water which is too hot. In worst cases where the hot water is too hot, there may be a scald hazard to persons using hot water directly (e.g. sinks or shower). In applications using higher pressure or higher flow rates, building hot water temperature control can be more difficult. In a feedforward control system, an action is taken according to a measured value. The actions are pre-programmed for expected measured values. Unlike a feedback system, the feedforward control system does not automatically adjust to control the measured value, but rather simply measures the value, then takes the pre-determined action based on the measurement, as an open loop control system. One advantage of a feedforward system is that actions can be taken relatively quickly and decisively, consistent with an operating speed of the controlling device, actuator, valve, etc. However, especially as an open loop control system, there needs to be a causal relationship established and pre-determined, between the measured value and the quantity being controlled, as controlled, for example, by a proportional valve in a water heater system. Particularly in larger commercial settings, domestic hot water is typically provided by heating a supplied domestic cold water from any suitable cold water source, such as a domestic cold water connection to a municipal water source. Water heaters can use any suitable heat exchanger, where heat energy from any suitable source of heat energy (e.g. hot water from boiler) heats the domestic cold water by heat transfer within the heat exchanger. To better understand the new method of the Application, consider that in a more conventional approach of the prior art, one way to regulate the temperature of the hot water sent to the hot water pipes of the building is to measure the hot water temperature at the heat exchanger hot water outlet, and to take some controlled action based on that temperature to try to hold that temperature to desired value. Such control is a feedback type control, because the measured value is also the value being set by the control system. Rather than directly measuring the heat exchanger hot water outlet temperature, a measurement of the temperature of a mix of hot water from the outlet of the heat exchanger which feeds the hot water pipes of the building and the domestic cold water flowing into the heat exchanger can be used to provide a feedforward measured value, to control the rate of flow of boiler water into the heat exchanger, to regulate the temperature of the domestic hot water supply. U.S. Pat. No. 9,243,848, WATER HEATING SYSTEM, describes an earlier improvement of control of a gas fired burner based on such a mixed water feedforward value. Because of the overall control system structure, the heat exchanger structure, and the response time of the gas fired burner, in the system of the '848 patent, it was possible to measure the mix water temperature in the regular piped connections. The water heater system of the '848 patent is self-contained in that the burner which provides a heated gas to the heat exchanger is self-contained within the same water heater cabinet. The '848 patent is also assigned to AERCO International, Inc., and is incorporated herein by reference in its entirety for all purposes. In some commercial heating applications, there are alternative distributed systems, where, for example, a boiler system provides hot water to a separate heat exchanger in a different physical assembly, such as can be mounted on a different base or skid from the boiler. One problem in such a distributed system is that the time relationship between some types of flow valves, such as where heat energy into a heat exchanger is set by controlling the flow of boiler water into the heat exchanger (as opposed to direct gas fired heated gas) is more complex, precluding the direct measurement of mix water which was possible, for example, in the self-contained gas fired water heater of the'848 patent. In a typical distributed system with a separate boiler and domestic hot water heater, the domestic hot water heater accepts boiler water to heat a source of potable domestic cold water to provide domestic hot water. The temperature of the boiler water is set by the boiler, and the boiler is typically not directly part of the control system of the water heater of the Application (i.e. the boiler may have a separate controller which established the temperature of the boiler water). The water heater of the Application accepts the boiler water and controls heat energy input to the heat exchanger type water heater by varying the flow of boiler water into the heat exchanger. The flow of boiler water into the heat exchanger of the water heater of the Application by a three-way valve. The three-way proportional valve divides the incoming boiler water proportionally between the flow to the water heater inlet, and a diversion path back to the boiler. At one end of the range of the three-way proportional valve, the most heat energy is supplied to heat exchanger when substantially all of the boiler water is provided to the heat exchanger boiler inlet, and substantially none of the boiler water is returned by the three-way proportional valve to the boiler. Conversely, the minimum heat energy is supplied to heat exchanger when substantially none of the boiler water is provided to the heat exchanger boiler inlet, and substantially all of the boiler water is returned by the three-way proportional valve to the boiler. More typically, the three-way proportional valve operates continuously somewhere between these two extreme positions, regulating the flow of heat energy into the heat exchanger as controlled by the heat exchanger control system. This relationship is described hereinbelow in more detail by an example as shown inFIG.4. In the prior art, the controller typically runs a feedback control system where the heat exchanger hot water heater controls the three-way proportional valve in response to a measurement of the domestic hot water temperature at the domestic hot water outlet of the heat exchanger. As described hereinbelow by the Application, it was realized that a control of the flow rate of hot water (e.g. from a boiler) into a separate heat exchanger assembly can be more efficiently controlled based on an open loop feedforward measured value of the mix of hot water from the outlet of the heat exchanger which feeds the hot water pipes of the building and the domestic cold water flowing into the heat exchanger. However, for the very different structure of three-way proportional valve to control the flow of boiler water into a heat exchanger, a direct measurement of mix water in the existing standard piping, was found to be inoperative for feedforward control. In a feedforward system, the time relationship between the measured temperature value and the action of an actuator, here a proportional flow valve, should be aligned, such that there is a causal relationship between the measured temperature and the action of the valve. The valve operating time should be accounted for, so that the regulating action now corresponds causally to the measured feed forward mix water value. Without, such a causal system, the control system will be ineffective at best, and unstable at worst. Therefore, in a separate boiler, heat exchanger distributed system, it was realized that there is also a need for a fluid delay element, which provides a desired delay to establish a causal feedforward control system to provide a stable control of the heat exchanger hot water outlet temperature. Another problem is that there needs to be a structure to provide good mixing of the hot water from the outlet of the heat exchanger which feeds the hot water pipes of the building and the domestic cold water flowing into the heat exchanger to obtain a reliable, accurate, and robust feedforward temperature measurement value. It was realized that one or more tanks including at least one mixing tank can solve both problems, to provide both the mixing action, and the desired fluid delay time. The mixing tank can include a mixing chamber, where the domestic cold water supply to the heat exchanger cold water inlet, mixes with hot water pumped from the hot water outlet of the heat exchanger. The pump is a constant flow type pump so as to establish known conditions for the development of a feedforward relationship (e.g. a look-up table in a controller) between the measured mix temperature and desired proportional valve settings. Moreover, by providing a baffle between the first mixing chamber and a second chamber, the length of the flow path can be increased, to provide another feature of the mixing tank, the desired fluid delay time. The delay time can also be set in part by the ratio between the diameter of the pipes supplying the domestic cold water supply to the heat exchanger cold water inlet and the pipe providing the hot water pumped from the hot water outlet of the heat exchanger to the mixing tank, and the diameter of the mixing tank (or, the relative size of the chambers to the diameter of the supply pipes). FIG.1Ashows an exemplary feedforward control system according to the Application. In the exemplary embodiment ofFIG.1A, one mixing tank provides both of the desired mixing and fluid delay properties. The mixing property is enhanced by an internal baffle. Note that is unimportant whether the mixing action and fluid delay is incorporated into a single mixing tank, or if mixing and fluid delay are distributed between a mixing tank and one or more additional tanks or fluid delay lines (e.g. literally physical lengths of pipe to cause a fluid delay). As will be understood by those skilled in the art, desired fluid delays can be established by the ratio of the diameter of the pipes which couple the heat exchanger to the source of domestic cold water and the domestic hot water constant flow pipe, and the diameter and length of any fluid delay line pipe diameter and length and/or the diameter and length of any of the mixing tank and/or any additional delay tanks. However, in all of the above options, the mixing and delay features are provided by adding tanks and/or pipes which otherwise would not be present to merely fluidly couple (plumb) the various components together. Part of what is new is the realization that in addition to enhanced mixing, what is needed is an additional fluid delay time, which otherwise would not be present by normal structural connective plumbing, pipes, of a prior art assembly. The desired fluid delays are added by one or more tanks and/or elongated connecting pipes having a fluid flow path greater than what would have been the direct connections between components of a prior art water heater. Now, referring toFIG.1Ain more detail, the solution of the Application provides a regulated temperature hot water supply153to the domestic hot water supply pipes of the building. The domestic hot water heater100uses a heat exchanger120. The source of heat energy to heat the domestic hot water is a separate boiler (not shown inFIG.1A). Boiler water150(hot “boiler” water from the boiler) is fluidly coupled to the heat exchanger boiler input121via a 3-way proportional valve160. Boiler water150, as provided by 3-way proportional valve160to heat exchanger120, and returns at least in part (i.e., when there is boiler water flowed to the heat exchanger by the 3-way proportional valve160) to the boiler as low temperature boiler return water159(much of the heat of the boiler water, having been removed by heating the domestic cold water through the heat exchange surfaces of the heat exchanger120). The flow rate of boiler water150to the heat exchanger boiler input121is controlled by the 3-way proportional valve160, where for the lower flows, the 3-way proportional valve160can divert high temperature boiler water directly back to the boiler (not shown inFIG.1A) as boiler return water157, or for higher flows the 3-way proportional valve can provide a higher flow of boiler water with less diversion of boiler return water157to the boiler. Any flow of boiler water150not diverted via the 3-way proportional valve160back to the boiler as boiler return water157, returns to the boiler having flowed through the heat exchanger120as a low temperature boiler return water159. In some embodiments, such as the exemplary system ofFIG.1A, a boiler can have separate inlets to receive both a high temperature return water157, as well as a low temperature return water159. An advantage of such dual returns is that the boiler can heat the boiler water more efficiently by condensation caused by the lower temperature return water159. One such boiler is the Benchmark® Platinum condensing boiler, available from AERCO International, Inc. of Blauvelt, N.Y. Alternatively, the boiler water from the 3-way proportional valve160could be combined with the boiler return water from the heat exchanger120, however, then the total return water to the boiler, particularly where more boiler water is returned by the 3-way proportional valve160, will be warmer, and a condensing type boiler will operate less efficiently. The alternative system can be completely operational, just less efficient overall. Mixing tank180accepts hot water from the heat exchanger domestic hot water outlet123as pumped via pump170at the mixing tank hot water inlet183and cold domestic cold water155via the mixing tank cold water inlet181. The mixed water is fed to the heat exchanger cold water inlet125from the mixing tank mixed water outlet185. The temperature of the domestic hot water at the heat exchanger domestic hot water outlet123is regulated to a desired temperature. However, in contrast to a traditional closed loop feedback system, a measured value of the domestic hot water supply153is not the measured temperature value used for control. Rather, in the feedforward system according to the Application, the temperature of the mixed water is measured by temperature sensor995(or, in other embodiments, a flow meter of the domestic cold water into the heat exchanger, as described in more detail hereinbelow). The mixed water temperature can be measured at suitable location in either chamber of the mixing tank180. In some embodiments, good results have been obtained by measuring mixed water temperature near the top of the first mix chamber. The mixed water temperature as measured by temperature sensor995is operatively conveyed by any suitable communications means, typically a wired connection993, to controller990. Controller990is any suitable processor based computer, typically a programmable logic controller (PLC), or alternatively any suitable processor, computer, microcomputer, etc. In some embodiments a controller may include more than one processor, such details of the controller are unimportant to the Application. 3-way proportional control valve160is also operatively conveyed (operationally coupled) by any suitable communications means, typically by a wired connection991, to controller990. Controller990runs a feedforward process which includes any suitable equation and/or lookup table to set the position of the proportional 3-way valve corresponding to any particular measured mixed water temperature to control the temperature of the domestic hot water supply153to any suitable desired value. Improved accuracy—While feedforward control alone can provide a fully operational system with good temperature regulation, there can be some error between an operator set point temperature (e.g. an absolute desired hot water outlet temperature) and the actual regulated hot water outlet temperature (a bias error). That is, the hot water outlet temperature will be well controlled and regulated, but possibly at a slightly different temperature than the desired setpoint temperature. For an improved system absolute accuracy, there can be an additional feedback path which provides an error term to the controller based on an actual measurement of the hot water outlet temperature. Note that this second feedback element is still quite different than a conventional feedback loop of the prior art, where now the feedback parameter being controlled is the error term or the difference between actual outlet hot water temperature997,FIG.1A, and the set-point desired hot water temperature at the domestic hot water supply153by the operator (set point not shown inFIG.1A, understood to be set by user interface device connected to controller990, such as, for example, any suitable: user buttons, numeric displays, LED or LCD graphical display, touchscreen, or any suitable combination thereof). An adaptive filter alone in the feed-forward path that works to minimize the measured error could also be used, i.e. not a PID type of controller where the gains are preset and can only be changed via manual intervention, but rather a fully automatic correction system. In summary, in this approach, there is the basic feedforward system ofFIG.1A, combined with a temperature sensor which measures the hot water outlet temperature, and which defines an error value within the process control program running on the controller990such that the hot water outlet water more closely follows absolutely, an operator set point temperature for the hot water. Exemplary control loop—FIG.1Cis a drawing showing an exemplary control loop diagram illustrating control by mixed water temperature and outlet temperature (the optional feedback to reduces offset error. The water heaters of the application include a heat exchanger (PFHX), such as, for example heat exchanger120ofFIG.1A. In the exemplary control system ofFIG.1C, the feedforward value is either the mixed water temperature (FIG.1A), or the flow rate (e.g. GPM) of the domestic cold water into the water heater (FIG.1B). It turns out that where the feedback is a flowrate value, the adaptive filter typically used with a mixed water temperature feedforward value can be replaced with a simple PID control, or even a relatively simple ladder-logic solution of a typical programmable logic controller (PLC). Alternative to feedback correction—In an alternative system where there is no feedback correction based on an actual measurement of the hot water outlet temperature, there can be an additional temperature sensor to measure the Domestic Cold water inlet temperature998,FIG.1, to run only feedforward control (this is temperature T2in the excel spreadsheet). The temperature set-point (T1) and measure T3(mix temperature) are known, so an equation can be used to figure inlet flow rate and therefore valve position. Such an example is described in more detail hereinbelow with regard toFIG.4. Constant flow pump—As use herein, “constant flow” does not mean only one flow rate, rather for a desired or pre-set flow rate, the flow rate is a substantially constant desired or pre-set flow rate. For example, there can be a fixed speed constant flow rate that only provides one fixed flow rate determined at time of manufacture. Or, in other embodiments, there can be a variable speed pump, which can provide either increments or more typically a continuum of settable constant flow rates. In other words, the constant flow pump can optionally be a variable speed pump having a plurality of preset or selectable constant flow rates. Such variable speed pumps are well known in the art. The use of a Variable Speed pump (e.g. for pump170) can help the Signal-to-Noise ratio of the measured mixed water temperature. Such an improvement of the S/N of the measured mixed water temperature value can be an adaptive process. Or, there can be a pre-determined relationship, set at time of manufacture, time of installation, or set as a function of the temperature setpoint and inlet water temperature. For example, the greater the difference between the setpoint temperature and the inlet supply temperature, the better the signal-to-noise in the measured mix-temperature. Mixed water temperature S/N can be so improved, for example, by flowing more recirculation water into the mix tank. See for example: the slope of the line at the higher flow rates in the excel spread sheet,FIG.4, such as, at 90 GPM to 80 GPM. Mixing tank—An exemplary mixing tank is shown inFIG.2AandFIG.2B.FIG.2Ais a top view of an exemplary mixing tank200according to the Application in more detail. There are two chambers, mixing chamber201(which also adds fluid delay time) and delay chamber203. Mixing chamber201is separated from delay chamber203by baffle211. As seen in the top view ofFIG.2A, baffle211can optionally include a V-shaped (here a relatively shallow “open” V-shaped bend) to enhance the mixing efficiency of the cold water and the constant flow hot water. Mixing tank hot water inlet183accepts hot water such as, for example, from a heat exchanger domestic hot water outlet123as pumped via pump170as shown inFIG.1A. Mixing tank cold water inlet181receives cold water, such as, for example, from a domestic cold water inlet155,FIG.1A. The details of the mechanical type couplings and/or fluid connections and directions (e.g. elbows or not) at any of the inlets or outlet of the mixing tank can be of any suitable type, and the types of fluid coupling and directions of coupling to the exterior of the mixing tank are unimportant. The mixed water outlet185provides mixed water, for example, to the heat exchanger cold water inlet125,FIG.1A. The mixed water temperature above the baffle211can be sensed via access port221.FIG.2Bis a section view of the mixing tank ofFIG.2Aand shows how water flows from the mixing chamber201through an opening in the baffle, to the delay chamber203. Note that in the exemplary embodiment ofFIG.2B, both inlets and outlets are placed relatively low and distant from the opening in the baffle to increase the length over which the mixed water flows from the mixed chamber to the outlet for a desired fluid delay time. The fluid delay time is established by a combination of the ratio of the diameter of the inlet pipes to the diameter of the mix tank, as well as the length of the fluid flow from inlets to outlet. For example, as the ratio of the diameter of the mix tank to the diameter of the inlet pipes increases, the flow rate is decreased, and the fluid delay time is increased. Similarly, if the length of the mix tank is increased (and/or if additional baffles are used for a serpentine fluid path), the fluid delay time increases. FIG.2Cis a drawing showing a perspective view of another exemplary mixing tank.FIG.2Dis a drawing showing a top view of the mixing tank ofFIG.2C.FIG.2Eis a drawing showing a side view of the mixing tank ofFIG.2C.FIG.2Fis a drawing showing a different side view of the mixing tank ofFIG.2C.FIG.2Gis a drawing showing another different side view of the mixing tank ofFIG.2C. Heat exchanger—Any suitable heat exchanger can be used. Exemplary implementations used a plate heat exchanger, specifically a SmartPlate exchanger available from AERCO International, Inc. of Blauvelt, N.Y. Exemplary suitable heat exchanger units include any suitable heat exchanger heater which can be used with boiler water on one side and domestic water heater on the other side such that the higher temperature boiler water heats the domestic water. Example—Water heater skid—A feedforward boiler water heat exchanger water heater according to the Application was built and tested as shown inFIG.3AtoFIG.3G.FIG.3Ais a drawing showing a perspective view the water heater skid of a feedforward boiler water heat exchanger water heater according to the Application.FIG.3Bis a drawing showing a top view of the water heater ofFIG.3A.FIG.3Cis a drawing showing a different perspective view of the water heater ofFIG.3A.FIG.3Dis a drawing showing a left side view of the water heater ofFIG.3A.FIG.3Eis a drawing showing a front view of the water heater ofFIG.3A.FIG.3Fis a drawing showing a right side view of the water heater ofFIG.3A.FIG.3Gis a drawing showing a back view of the water heater ofFIG.3A. Example—A hot water was built according toFIG.3AtoFIG.3G. The physical dimensions of the entire unit as mounted on a common skid were about 30″ wide by about 30″ deep by about 55″ high. The relatively small foot print and small volume assembly was found to provide a heating capacity of about 4.5 million BTU for a surprising efficient instant water heater in such a compact form factor. The hot water heater was found to maintain about +/−1° F. for steady water flow rates (about constant demand), and about +/−6° F. for relatively large (i.e. >50%) load changes, and about +/−4° F. for a <50% load change. FIG.4is a MS Excel spread sheet showing an exemplary feedforward process relationship and equation. The Excel spread sheet shows an exemplary model of the controllable three-way proportional valve position on the supply side to the heat exchanger as a function of mixed water temperature. As can been seen in the graphs ofFIG.4, the relationship is highly non-linear. One problem is that conventional linear fits (first order) of the prior art would be less efficient, or even inoperative in this feedforward process. Better feedforward control can be achieved by use of 2ndorder or higher polynomial for this relationship. Because the relationship is dependent on maximum flow rates and set point and entering water temperatures, for this exemplary model, a 140 F set point is used with a 55 F entering (supply) water for the domestic side with a maximum flow of 90 GPM (maximum BTU's). It was realized that higher order modeling for the feed-forward loop, as shown for example by the graph on the right side ofFIG.4can be used for a more accurate feedforward process for a water heater according to the application. Example—In the exemplary feedforward process ofFIG.4, a prior art controller may have attempted control by a linear feedforward process equation, y=−0.4407x+94.206, as shown by the graph on the left side ofFIG.4. However, a more accurate feedforward process was realized by the exemplary higher order (6th) polynomial, y=2E-09x6-8E-07x5+0.0001x4-0.0071x3+0.267x2-5.7989x+130.36, as shown in the graph on the right side ofFIG.4. Flow meter (flow sensor,1001,FIG.1B)—Alternative to feedforward based on a mix tank mixed water temperature—The mixed water temperature parameter can be replaced by a GPM value, such as can be measured by a flowmeter on the cold water supply line. Such an alternative feedforward control system can use a relatively simple control, such as, for example a PID (proportional, integral, derivative) controller. Note that the controllable three-way proportional valve is a linearized valve, i.e. GPM is a substantially linear function of valve position. Especially where the valve is a linearized valve, i.e. GPM is a substantially linear function of valve position, a flow-rate measurement on the domestic cold water side, can be correlated by a feedforward process directly to the controllable three-way proportional valve position. Therefore, it was realized that a flow-rate measurement on the domestic cold water side, such as by any suitable flow meter, can be used as an alternative to the mix water temperature as the feedforward sensor value. FIG.1Bis a drawing showing a schematic diagram of a hot water system with a flowmeter1001flow rate value as the feedforward parameter for a hot water heater. A flowrate sensor is not shown inFIG.1A. In some embodiments, a flow rate sensor can be operatively coupled to the processor, where the water heater runs on a feedforward process to control a controllable three-way linearized proportional valve based on a measured flow rate of the domestic cold water entering the heat exchanger. The flow sensor1001(GPM or velocity) is shown upstream of optional recirculation water pump170merely for illustration purposes. Where there is an optional pump170present, flow sensor1001can also be located downstream. The process controller (e.g. running a PID process) would adjust accordingly. The upstream measurement indicates the demand rate of hot water. Where a flowmeter is used to provide a feedforward value of domestic cold water inlet flow rate in place of a temperature of mix water in a mix tank, a mix tank is not required. Similarly, the pump is also not required, however can still be optionally present, such as to help prevent scale build up in the heat exchanger, especially during times of near zero hot water supply loads. The pump can also provide other advantages of periodic or constant recirculation of hot water, such as for better heat transfer and more efficient thermal management (e.g. heat transfer from the boiler water to the hot water) on both sides of the heat exchanger. Summary—In summary, and with respect to the exemplary embodiment ofFIG.1A, a water heater100includes a heat exchanger120(hx) having a hx hot water inlet121, a hx water return outlet127, a hx domestic cold water inlet125, and a hx domestic hot water outlet123. A controllable three-way proportional valve160has a boiler water hot water inlet150adapted to accept a boiler water, and to provide a proportionally controllable flow to the hx hot water inlet121and boiler return water outlet157. The boiler return water outlet157is adapted to return a boiler return water to a boiler. A mixing tank180(mt) has a mt cold water inlet181adapted to receive a cold water from a source of domestic cold water155, a mt hot water inlet183, and a mt mixed water outlet185. The mixing tank180mixes the cold water and a hot water from the mt hot water inlet183. The mixing tank180provides a time delayed mixed water. A constant flow pump170is fluidly coupled to and disposed between the hx domestic hot water outlet123and the mt hot water inlet183. A temperature sensor995is disposed in or on the mixing tank180to measure a temperature of the time delayed mixed water to provide a time delayed mixed water temperature. A processor990is operatively coupled to the temperature sensor995and operatively coupled to the controllable three-way proportional valve160. The processor990runs a feedforward control process based on the temperature of the time delayed mixed water to control a flow of boiler water into the heat exchanger120. The feedforward control process adjusts a proportional operating position of the controllable three-way proportional valve160to regulate a temperature of hot water at the hx domestic hot water outlet153based on the temperature of the time delayed mixed water temperature. Software and/or firmware for the controller, including the feedforward process based on mixed water temperature can be provided on a computer readable non-transitory storage medium. A computer readable non-transitory storage medium as non-transitory data storage includes any data stored on any suitable media in a non-fleeting manner. Such data storage includes any suitable computer readable non-transitory storage medium, including, but not limited to hard drives, non-volatile RAM, SSD devices, CDs, DVDs, etc. It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims. | 32,269 |
RE49884 | DETAILED DESCRIPTION Turning now to the drawings, and referring first toFIG.1, a biological sample imaging system10is illustrated diagrammatically. The biological sample imaging system10is capable of imaging multiple biological components12,14within a support structure16. For instance, in the illustrated embodiment, a first biological component12may be present on a first surface18of the support structure16while a second biological component14may be present on a second surface20of the support structure. The support structure16may, for instance, be a flow cell with an array of biological components12,14on the interior surfaces18,20which generally mutually face each other and through which reagents, flushes, and other fluids may be introduced, such as for binding nucleotides or other molecules to the sites of biological components12,14. The support structure16may be manufactured in conjunction with the present techniques or the support structure16may be purchased or otherwise obtained from a separate entity. Fluorescent tags on the molecules that bind to the components may, for instance, include dyes that fluoresce when excited by appropriate excitation radiation. Assay methods that include the use of fluorescent tags and that can be used in an apparatus or method set forth herein include those set forth elsewhere herein such as genotyping assays, gene expression analysis, methylation analysis, or nucleic acid sequencing analysis. Those skilled in the art will recognize that a flow cell or other support structure may be used with any of a variety of arrays known in the art to achieve similar results. Furthermore, known methods for making arrays can be used, and if appropriate, modified in accordance with the teaching set forth herein in order to create a flow cell or other support structure having multiple surfaces useful in the detection methods set forth herein. Such arrays may be formed by disposing the biological components of samples randomly or in predefined patterns on the surfaces of the support by any known technique. In a particular embodiment, clustered arrays of nucleic acid colonies can be prepared as described in U.S. Pat. No. 7,115,400; U.S. Patent Application Publication No. 2005/0100900; PCT Publication No. WO 00/18957; or PCT Publication No. WO 98/44151, each of which is hereby incorporated by reference. Such methods are known as bridge amplification or solid-phase amplification and are particularly useful for sequencing applications. Other exemplary random arrays, and methods for their construction, that can be used in the invention include, without limitation, those in which beads are associated with a solid support, examples of which are described in U.S. Pat. Nos. 6,355,431; 6,327,410; and U.S. Pat. No. 6,770,441; U.S. Patent Application Publication Nos. 2004/0185483 and US 2002/0102578; and PCT Publication No. WO 00/63437, each of which is hereby incorporated by reference. Beads can be located at discrete locations, such as wells, on a solid-phase support, whereby each location accommodates a single bead. Any of a variety of other arrays known in the art or methods for fabricating such arrays can be used in the present invention. Commercially available microarrays that can be used include, for example, an Affymetrix® GeneChip® microarray or other microarray synthesized in accordance with techniques sometimes referred to as VLSIPS™ (Very Large Scale Immobilized Polymer Synthesis) technologies as described, for example, in U.S. Pat. Nos. 5,324,633; 5,744,305; 5,451,683; 5,482,867; 5,491,074; 5,624,711; 5,795,716; 5,831,070; 5,856,101; 5,858,659; 5,874,219; 5,968,740; 5,974,164; 5,981,185; 5,981,956; 6,025,601; 6,033,860; 6,090,555; 6,136,269; 6,022,963; 6,083,697; 6,291,183; 6,309,831; 6,416,949; 6,428,752; and 6,482,591, each of which is hereby incorporated by reference. A spotted microarray can also be used in a method of the invention. An exemplary spotted microarray is a CodeLink™ Array available from Amersham Biosciences. Another microarray that is useful in the invention is one that is manufactured using inkjet printing methods such as SurePrint™ Technology available from Agilent Technologies. Sites or features of an array are typically discrete, being separated with spaces between each other. The size of the sites and/or spacing between the sites can vary such that arrays can be high density, medium density, or lower density. High density arrays are characterized as having sites separated by less than about 15 μm. Medium density arrays have sites separated by about 15 to 30 μm, while low density arrays have sites separated by greater than 30 μm. An array useful in the invention can have sites that are separated by less than 100 μm, 50 μm, 10 μm, 5 μm, 1 μm or 0.5 μm. An apparatus or method of the invention can be used to image an array at a resolution sufficient to distinguish sites at the above densities or density ranges. As exemplified herein, a surface used in an apparatus or method of the invention is typically a manufactured surface. It is also possible to use a natural surface or a surface of a natural support structure; however the invention can be carried out in embodiments where the surface is not a natural material or a surface of a natural support structure. Accordingly, components of biological samples can be removed from their native environment and attached to a manufactured surface. Any of a variety of biological components can be present on a surface for use in the invention. Exemplary components include, without limitation, nucleic acids such as DNA or RNA, proteins such as enzymes or receptors, polypeptides, nucleotides, amino acids, saccharides, cofactors, metabolites or derivatives of these natural components. Although the apparatus and methods of the invention are exemplified herein with respect to components of biological samples, it will be understood that other samples or components can be used as well. For example, synthetic samples can be used such as combinatorial libraries, or libraries of compounds having species known or suspected of having a desired structure or function. Thus, the apparatus or methods can be used to synthesize a collection of compounds and/or screen a collection of compounds for a desired structure or function. Returning to the exemplary system ofFIG.1, the biological sample imaging system10may include at least a first radiation source22but may also include a second radiation source24(or additional sources). The radiation sources22,24may be lasers operating at different wavelengths. The selection of the wavelengths for the lasers will typically depend upon the fluorescence properties of the dyes used to image the component sites. Multiple different wavelengths of the lasers used may permit differentiation of the dyes at the various sites within the support structure16, and imaging may proceed by successive acquisition of a series of images to enable identification of the molecules at the component sites in accordance with image processing and reading logic generally known in the art. Other radiation sources known in the art can be used including, for example, an arc lamp or quartz halogen lamp. Particularly useful radiation sources are those that produce electromagnetic radiation in the ultraviolet (UV) range (about 200 to 390 nm), visible (VIS) range (about 390 to 770 nm), infrared (IR) range (about 0.77 to 25 microns), or other range of the electromagnetic spectrum. For ease of description, embodiments utilizing fluorescence-based detection are used as examples. However, it will be understood that other detection methods can be used in connection with the apparatus and methods set forth herein. For example, a variety of different emission types can be detected such as fluorescence, luminescence, or chemiluminescence. Accordingly, components to be detected can be labeled with compounds or moieties that are fluorescent, luminescent, or chemiluminescent. Signals other than optical signals can also be detected from multiple surfaces using apparatus and methods that are analogous to those exemplified herein with the exception of being modified to accommodate the particular physical properties of the signal to be detected. Output from the radiation sources22,24may be directed through conditioning optics26,28for filtering and shaping of the beams. For example, in a presently contemplated embodiment, the conditioning optics26,28may generate a generally linear beam of radiation, and combine beams from multiple lasers, for example, as described in U.S. Pat. No. 7,329,860. The laser modules can additionally include a measuring component that records the power of each laser. The measurement of power may be used as a feedback mechanism to control the length of time an image is recorded in order to obtain uniform exposure, and therefore more readily comparable signals. After passing through the conditioning optics26,28, the beams may be directed toward directing optics30which redirect the beams from the radiation sources22,24toward focusing optics32. The directing optics30may include a dichroic mirror configured to redirect the beams toward the focusing optics32while also allowing certain wavelengths of a retrobeam to pass therethrough. The focusing optics32may confocally direct radiation to one or more surfaces18,20of the support structure16upon which individual biological components12,14are located. For instance, the focusing optics32may include a microscope objective that confocally directs and concentrates the radiation sources22,24along a line to a surface18,20of the support structure16. Biological component sites on the support structure16may fluoresce at particular wavelengths in response to an excitation beam and thereby return radiation for imaging. For instance, the fluorescent components may be generated by fluorescently tagged nucleic acids that hybridize to complementary molecules of the components or to fluorescently tagged nucleotides that are incorporated into an oligonucleotide using a polymerase. As noted above, the fluorescent properties of these components may be changed through the introduction of reagents into the support structure16(e.g., by cleaving the dye from the molecule, blocking attachment of additional molecules, adding a quenching reagent, adding an acceptor of energy transfer, and so forth). As will be appreciated by those skilled in the art, the wavelength at which the dyes of the sample are excited and the wavelength at which they fluoresce will depend upon the absorption and emission spectra of the specific dyes. Such returned radiation may propagate back through the directing optics30. This retrobeam may generally be directed toward detection optics34which may filter the beam such as to separate different wavelengths within the retrobeam, and direct the retrobeam toward at least one detector36. The detector36may be based upon any suitable technology, and may be, for example, a charged coupled device (CCD) sensor that generates pixilated image data based upon photons impacting locations in the device. However, it will be understood that any of a variety of other detectors may also be used including, but not limited to, a detector array configured for time delay integration (TDI) operation, a complementary metal oxide semiconductor (CMOS) detector, an avalanche photodiode (APD) detector, a Geiger-mode photon counter, or any other suitable detector. TDI mode detection can be coupled with line scanning as described in U.S. Pat. No. 7,329,860. The detector36may generate image data, for example, at a resolution between 0.1 and 50 microns, which is then forwarded to a control/processing system38. In general, the control/processing system38may perform various operations, such as analog-to-digital conversion, scaling, filtering, and association of the data in multiple frames to appropriately and accurately image multiple sites at specific locations on a sample. The control/processing system38may store the image data and may ultimately forward the image data to a post-processing system (not shown) where the data are analyzed. Depending upon the types of sample, the reagents used, and the processing performed, a number of different uses may be made of the image data. For example, nucleotide sequence data can be derived from the image data, or the data may be employed to determine the presence of a particular gene, characterize one or more molecules at the component sites, and so forth. The operation of the various components illustrated inFIG.1may also be coordinated with the control/processing system38. In a practical application, the control/processing system38may include hardware, firmware, and software designed to control operation of the radiation sources22,24, movement and focusing of the focusing optics32, a translation system40, and the detection optics34, and acquisition and processing of signals from the detector36. The control/processing system38may thus store processed data and further process the data for generating a reconstructed image of irradiated sites that fluoresce within the support structure16. The image data may be analyzed by the system itself, or may be stored for analysis by other systems and at different times subsequent to imaging. The support structure16may be supported on a translation system40which allows for focusing and movement of the support structure16before and during imaging. The stage may be configured to move the support structure16, thereby changing the relative positions of the radiation sources22,24and detector36with respect to the surface bound biological components for progressive scanning Movement of the translation system40can be in one or more dimensions including, for example, one or both of the dimensions that are orthogonal to the direction of propagation for the excitation radiation line, typically denoted as the X and Y dimensions. In particular embodiments, the translation system40may be configured to move in a direction perpendicular to the scan axis for a detector array. A translation system40useful in the present invention may be further configured for movement in the dimension along which the excitation radiation line propagates, typically denoted as the Z dimension. Movement in the Z dimension can also be useful for focusing. FIG.2is a diagrammatical representation of an exemplary semi-confocal line scanning approach to imaging the support structure16. In the illustrated embodiment, the support structure16includes an upper plate42and a lower plate44with an internal volume46between the upper and lower plates42,44. The upper and lower plates42,44may be made of any of a variety of materials but may preferably be made of a substrate material that is substantially transparent at the wavelengths of the excitation radiation and the fluoresced retrobeam, allowing for the passage of excitation radiation and returned fluorescent emissions without significant loss of signal quality. Moreover, when used in epifluorescent imaging arrangements as shown, one of the surfaces through which the radiation traverses may be substantially transparent at the relevant wavelengths, while the other (which is not traversed by radiation) may be less transparent, translucent, or even opaque or reflective. The upper and lower plates42,44may both contain biological components12,14on their respective, inwardly facing surfaces18,20. As discussed above, the internal volume46may, for instance, include one or more internal passages of a flow cell though which reagent fluids may flow. The support structure16may be irradiated by excitation radiation48along a radiation line50. The radiation line50may be formed by the excitation radiation48from the radiation sources22,24, directed by the directing optics30through the focusing optics32. The radiation sources22,24may generate beams that are processed and shaped to provide a linear cross section or radiation line including a plurality of wavelengths of radiation used to cause fluorescence at correspondingly different wavelengths from the biological components12,14, depending upon the particular dyes used. The focusing optics32may then semi-confocally direct the excitation radiation48toward the first surface18of the support structure16to irradiate sites of biological component12along the radiation line50. In addition, the support structure16, the directing optics30, the focusing optics32, or some combination thereof, may be slowly translated such that the resulting radiation line50progressively irradiates the component as indicated by the arrow52. This translation results in successive scanning of regions54which allow for the gradual irradiation of the entire first surface18of the support structure16. As will be discussed in more detail below, the same process may also be used to gradually irradiate the second surface20of the support structure16. Indeed, the process may be used for multiple surfaces within the support structure16. Exemplary methods and apparatus for line scanning are described in U.S. Pat. No. 7,329,860, which is incorporated herein by reference, and which describes a line scanning apparatus having a detector array configured to achieve confocality in the scanning axis by restricting the scan-axis dimension of the detector array. More specifically, the scanning device can be configured such that the detector array has rectangular dimensions such that the shorter dimension of the detector is in the scan-axis dimension and imaging optics are placed to direct a rectangular image of a sample region to the detector array such that the shorter dimension of the image is also in the scan-axis dimension. In this way, semi-confocality can be achieved since confocality occurs in a single axis (i.e. the scan axis). Thus, detection is specific for features on the surface of a substrate, thereby rejecting signals that may arise from the solution around the feature. The apparatus and methods described in U.S. Pat. No. 7,329,860 can be modified such that two or more surfaces of a support are scanned in accordance with the description herein. Detection apparatus and methods other than line scanning can also be used. For example, point scanning can be used as described below or in U.S. Pat. No. 5,646,411, which is incorporated herein by reference. Wide angle area detection can be used with or without scanning motion. As set forth in further detail elsewhere herein, TIR methods can also be used. As illustrated generally inFIG.2, the radiation line50used to image the sites of biological components12,14, in accordance with the present invention, may be a continuous or discontinuous line. As such, some embodiments of the present invention may include a discontinuous line made up of a plurality of confocally or semi-confocally directed beams of radiation which nevertheless irradiate a plurality of points along the radiation line50. These discontinuous beams may be created by one or more sources that are positioned or scanned to provide the excitation radiation48. These beams, as before, may be confocally or semi-confocally directed toward the first or second surfaces18,20of the support structure16to irradiate sites of biological component12,14. As with the continuous semi-confocal line scanning described above, the support structure16, the directing optics30, the focusing optics32, or some combination thereof, may be advanced slowly as indicated by arrow52to irradiate successive scanned regions54along the first or second surfaces18,20of the support structure16, and thereby successive regions of the sites of biological components12,14. It should be noted that the system will typically form and direct excitation and returned radiation simultaneously for imaging. In some embodiments, confocal point scanning may be used such that the optical system directs an excitation point or spot across a biological component by scanning the excitation beam through an objective lens. The detection system images the emission from the excited point on the detector without “descanning” the retrobeam. This occurs since the retrobeam is collected by the objective lens and is split off the excitation beam optical path before returning back through the scan means. Therefore, the retrobeam will appear on the detector36at different points depending on the field angle of the original excitation spot in the objective lens. The image of the excitation point, at the detector36, will appear in the shape of a line as the excitation point is scanned across the sample. This architecture is useful, for example, if the scan means cannot for some reason accept the retrobeam from the sample. Examples are holographic and acoustic optic scan means that are able to scan a beam at very high speeds but utilize diffraction to create the scan. Therefore, the scan properties are a function of wavelength. The retrobeam of emitted radiation is at a different wavelength from the excitation beam. Alternatively or additionally, emission signals may be collected sequentially following sequential excitation at different wavelengths. In particular embodiments, an apparatus or method of the invention can detect features on a surface at a rate of at least about 0.01 mm2/sec. Depending upon the particular application of the invention, faster rates can also be used including, for example, in terms of the area scanned or otherwise detected, a rate of at least about 0.02 mm2/sec, 0.05 mm2/sec, 0.1 mm2/sec, 1 mm2/sec, 1.5 mm2/sec, 5 mm2/sec, 10 mm2/sec, 50 mm2/sec, 100 mm2/sec, or faster. If desired, for so example, to reduce noise, the detection rate can have an upper limit of about 0.05 mm2/sec, 0.1 mm2/sec, 1 mm2/sec, 1.5 mm2/sec, 5 mm2/sec, 10 mm2/sec, 50 mm2/sec, or 100 mm2/sec. In some instances, the support structure16may be used in such a way that biological components are expected to be present on only one surface. However, in many instances, biological material is present on multiple surfaces within the support structure16. For instance,FIG.3illustrates a typical support structure16where biological material has attached to the first surface18as well as to the second surface20. In the illustrated embodiment, an attachment layer56has formed on both the first surface18and the second surface20of the support structure16. A first excitation radiation58source may be used to irradiate one of many sites of biological component12on the first surface18of the support structure16and return a first fluorescent emission60from the irradiated biological component12. Simultaneously or sequentially, a second source of excitation radiation62may be used to irradiate one of many sites of biological component14on the second surface20of the support structure16, and return a second fluorescent emission64from the irradiated biological component14. Although the embodiment exemplified inFIG.3shows excitation from source58and source62coming from the same side of the support structure16, it will be understood that the optical system can be configured to impinge on the surfaces from opposite sides of the support structure16. TakingFIG.3as an example, upper surface18can be irradiated from excitation source58as shown and the lower surface20can be irradiated from below. Similarly, emission can be detected from one or more sides of a support structure. In particular embodiments, different sides of the support structure16can be excited from the same radiation source by first irradiating one side and then flipping the support structure to bring another side into position for excitation by the radiation source. The distribution of biological components12,14may follow many different patterns. For instance,FIG.4illustrates a support structure16where the biological components12,14at sites or features on the first and second surfaces18,20are distributed evenly in a spatially ordered pattern66of biological component sites68. For example, certain types of microarrays may be used where the location of individual biological component sites68may be in a regular spatial pattern. The pattern can include sites at pre-defined locations. In contrast, in other types of biological imaging arrays, biological components attach to surfaces at sites that occur in random or statistically varying positions such that imaging the microarray is used to determine the location of each of the individual biological component features. Thus, the pattern of features need not be pre-determined despite being the product of a synthetic or manufacturing process. For instance,FIG.5illustrates a support structure16where the sites on the first and second surfaces18,20are located in a random spatial distribution70of biological component sites72. However, with both fixed arrays66and random distribution70of biological sample sites, imaging of multiple surfaces18,20of the support structure16may be possible. In addition, it should be noted that in both instances, the biological components at the individual sites may constitute either a population of identical molecules or a random mix of different molecules. Furthermore, the density of biological samples may vary and may be at least 1,000 sites per square millimeter. The present techniques accommodate such varied physical arrangements of the multiple surfaces within the support structure16, as well as the varied disposition of the sites within components on the surfaces. As discussed above with reference toFIGS.2and3, in the embodiments with a support structure16having a first surface18and a second surface20, a first source of excitation radiation58may irradiate sites of biological component12on the first surface18, and return a first fluorescent emission60, while a second source of excitation radiation62may irradiate sites of biological component14on the second surface20and return a second fluorescent emission64source, as illustrated inFIG.3. Thus, components of the volume of sample between two surfaces need not be detected and can be rejected. Selective detection of a surface of a support structure provides preferential detection of the surface compared to the volume of the support structure adjacent the surface and compared to one or more other surfaces of the support structure. In more complex configurations, it may be useful to irradiate more than two surfaces. For instance,FIG.6illustrates a support structure16having N number of plates including a first plate42, a second plate44, . . . , an N-2 plate74, an N-1 plate76, and an N plate78. These plates define M number of surfaces including a first surface18, a second surface20, ... , an M-3 surface80, an M-2 surface82, an M-1 surface84, and an M surface86. In the illustrated embodiment, not only the first surface18and the second surface20of the support structure16may be irradiated but, rather, all M number of surfaces may be irradiated. For instance, a source of excitation radiation88may be used to irradiate biological component sites on the Mth surface86of the support structure16and return a fluorescent emission90from the irradiated biological component. For support structures having a plurality of surfaces it may be desirable to excite upper layers from the top and lower layers from the bottom to reduce photobleaching. Thus, components on layers that are closer to a first exterior side of a support structure can be irradiated from the first side, whereas irradiation from the opposite exterior side can be used to excite components present on layers that are closer to the opposite exterior side. FIG.7illustrates an objective92through which radiation from emissive biological components12,14on first and second surfaces18,20, respectively, of the support structure16may be detected. The objective92may be one of the components of the focusing optics32described above. Although not drawn to scale,FIG.7illustrates exemplary dimensions between the objective92and the support structure16. For instance, the objective92may typically be spaced approximately 600 or more microns from the upper plate42of the support structure16. The biological sample imaging system10may be configured to detect emitted radiation from biological components12on the first surface18through 300 microns of the upper plate42which may, for instance, be made of glass and may have a refractive index Ndof 1.472. In addition, the biological sample imaging system10may also be configured to detect emitted radiation from biological components14on the second surface20through 300 microns of the upper plate42plus 100 microns of the fluid within the internal volume46of the support structure46. In certain embodiments, the objective92may be designed for diffraction-limited focusing and imaging on only one of the first or second surfaces18,20of the support structure16. For example throughout the present description ofFIGS.7through14, the objective92may be designed for pre-compensation of the 300 microns of the upper plate42plus the 100 micron read buffer of the fluid within the internal volume46of the support structure16. In such a scenario, diffraction-limited performance may only be possible on the second surface20. Furthermore, the spherical aberration introduced by the 100 micron read buffer may severely impact the imaging quality when imaging from the first surface18. However, reducing the lane thickness of the internal volume46of the support structure16might increase the amount of surface-to-surface “crosstalk.” Therefore, perhaps the most appropriate solution is to correct the aberration. As such, it may be necessary to use a compensator capable of achieving diffraction-limited imaging performance on both the first and second surfaces18,20of the support structure16. It should be noted that the need for a compensator may be more pronounced when using objectives92with high numerical aperture (NA) values. Exemplary high NA ranges for which the invention is particularly useful include NA values of at least about 0.6. For example, the NA may be at least about 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, or higher. Those skilled in the art will appreciate that NA, being dependent upon the index of refraction of the medium in which the lens is working, may be higher including, for example, up to 1.0 for air, 1.33 for pure water, or higher for other media such as oils. The compensator may also find use in objectives having lower NA values than the examples listed above. In general, the NA value of an objective92is a measure of the breadth of angles for which the objective92may receive light. The higher the NA value, the more light that may be collected by the objective92for a given fixed magnification. This is because the collection efficiency and the resolution increase. As a result, multiple objects may be distinguished more readily when using objectives92with higher NA values because a higher feature density may be possible. Therefore, in general, a higher NA value for the objective92may be beneficial for imaging. However, as the NA value increases, its sensitivity to focusing and imaging-through media thickness variation also increases. In other words, lower NA objectives92have longer depth of field and are generally not as sensitive to changes in imaging-through media thickness. FIG.8is an exemplary chart94of spherical aberration (in waves) vs. thickness (in microns) of the upper plate42of the support structure16ofFIG.7in accordance with the present invention. Specifically, the upper line96of the graph depicts the amount of spherical aberration of an image taken from biological components12on the first surface18of the support structure16while the lower line98of the graph depicts the amount of spherical aberration of an image taken from biological components14on the second surface20of the support structure16. In the illustrated embodiment, the spherical aberration generated by the 100 micron read buffer is around 4 waves, which is much higher than the diffraction-limited performance requirement of less than 0.25 waves, for instance. As illustrated, at 300 microns (i.e. the thickness of the upper plate42), the spherical aberration for the first surface18is around −13.2 waves (e.g., point100) while the spherical aberration for the second surface20is around −17.2 waves (e.g., point102).FIG.9Aillustrates exemplary images expected for the first and second surfaces18,20of the support structure16corresponding to the thickness of the upper plate42(i.e., 300 microns) in accordance with the present invention, where the imaging system is optimized for the second surface20(pre-compensated for −17.2 waves). As shown, the imaging system is capable of providing high image quality on the second surface20since, according to the present scenario, it was designed to do so. However, the images taken for the first surface18contain aberrations. To balance out the spherical aberration, it is beneficial to introduce an additional thickness (e.g., by introducing an additional coverslip) between the objective92and the support structure16. For instance, returning now toFIG.8, if an additional thickness of approximately 40 microns were to be introduced between the objective92and the first and second surfaces18,20of support structure16, the difference between the spherical aberrations at the design thickness (i.e., 300 micron upper plate plus 100 microns of fluid) may be split such that the image produced for both the first and second surfaces18,20may have similar quality. For instance, as illustrated, at 340 microns (i.e. the thickness of the upper plate42plus an additional 40 micron thickness), the spherical aberration for the first surface18is around −15.2 waves (e.g., point104) while the spherical aberration for the second surface20is around −19.2 waves (e.g., point106), splitting the difference of −17.2 waves (e.g., point108) which may be characterized as the design point for the objective92.FIG.9Billustrates exemplary images expected for the first and second surfaces18,20of the support structure16corresponding to the thickness of the upper plate42plus an additional thickness (i.e., 300 microns plus 40 microns) in accordance with the present invention, illustrating how the additional thickness may allow for balance between images taken for the first and second surfaces18,20of the support structure16. However, merely introducing an additional thickness between the objective92and the support structure16may not be desired for all uses of the imaging system set forth herein. For instance, as illustrated inFIGS.9A and9B, by simply introducing the additional 40 micron thickness between the objective92and the support structure16, images from both the first and second surfaces18,20may still experience residual aberration from the design point108of the objective92. Therefore, a more precise solution may be to only introduce the additional thickness when detecting radiation from biological components12on the first surface18of the support structure16. In such a scenario, the spherical aberration corresponding to the design point108of the objective92may generally be achieved for both the first and second surfaces18,20. It should be noted that the particular dimensions and measurements (e.g., thicknesses, spherical aberration values, and so forth) described with respect toFIGS.9A and9Bare merely intended to be exemplary of the manner in which the present invention functions. As such, these dimensions and measurements are not intended to be limiting. Indeed, the particular geometries and resulting measurement values may vary between implementations. For example,FIG.10Aillustrates an exemplary objective92imaging the second surface20of the support structure16without the assistance of a compensator110in accordance with the present invention. Without the compensator110, the objective92may focus and detect images from the second surface20of the support structure16according to its design and experiencing the design spherical aberration. However,FIG.10Billustrates an exemplary objective92imaging the first surface20of the support structure16with the assistance of a compensator110in accordance with the present invention. By using the compensator110(e.g., similar to the additional 40 micron thickness described above with respect toFIGS.8and9), the objective92may focus and detect images from the first surface18of the support structure16under similar conditions to that of its design point for the second surface20of the support structure16. Therefore, by detecting images for the second surface20without the compensator110and detecting images for the first surface18with the compensator110, the objective92may be capable of detecting images on both surfaces with diffraction-limited performance similar to the design of the objective92. The chromatic shift curve may be limited to wavelength ranges of between 530 nm to 780 nm. Chromatic shifts of different color wavelength bands may be compensated for by focusing the focusing optics32in each band. The compensator110should preferably be “invisible” to the focusing optics32. In other words, the compensator110should correct the spherical aberration difference of the read buffer but should maintain the chromatic shift curve in the wavelength range of 530-780 nm. More specifically, the chromatic shift relationships among the peak wavelengths of 560 nm, 610 nm, 687 nm, and 720 nm should be maintained. In addition, other specifications, including NA, field curvature, field distortion, detection magnification, and so forth, should also be maintained. Furthermore, the compensator110package should be relatively small (e.g., no more than 10 mm of total thickness). Moreover, insensitivity to positioning error of the compensator110may be preferred. Several various designs may be implemented to introduce the corrective optics of the compensator110into the optical train of the imaging optics of the biological sample imaging system10. For example,FIG.11is an exemplary compensator110design, incorporating a first objective92and a second objective112which may replace the first objective92in the optical train in accordance with the present invention. In the illustrated embodiment, each respective objective92,112may contain the optics required to image respective surfaces, such as the first and second surfaces18,20of the support structure16. For instance, the first objective92may contain the imaging optics necessary to focus on and image emissive biological components14on the second surface20of the support structure16while the second objective112may contain the imaging optics plus the corrective optics necessary to focus on and image emissive biological components12on the first surface18of the support structure16. In operation, the first objective92may detect images from the second surface20of the support structure16. The first objective92may be replaced by the second objective112in the optical train, at which point the second objective112may detect images from the first surface18of the support structure16. An advantage of the embodiment illustrated inFIG.11is that the optics may be decoupled and may operate independently. However, a disadvantage in some situations is that having two entirely separate objectives92,112may not be cost-effective since certain components may be duplicated for each objective92,112. Furthermore, in embodiments where multiple images of an object are obtained, the use of two objectives may increase the computational resources required for registration between images. In particular embodiments, imaging of both surfaces may occur through the same objective to provide particular advantages as set forth below. In other words, the first objective92need not be removed or replaced with the second objective112for imaging of the different surfaces. FIG.12is another exemplary compensator110design, incorporating a corrective device114which may be inserted between the objective92and the support structure16in accordance with the present invention. The corrective device114may, for instance, be a coverslip or other thin layer of glass. As illustrated, the corrective device114may simply be inserted into and removed from the optical path between the objective92and the support structure16depending on the particular surface16being imaged. For instance, the corrective device114may be removed from the optical path when the objective92is used to focus on and image emissive biological components14on the second surface20of the support structure16. Conversely, the corrective device114may be inserted into the optical path when the objective92is used to focus on and image emissive biological components12on the first surface18of the support structure16. An advantage of the embodiment illustrated inFIG.12is that it is relatively straightforward. The required additional compensator thickness may simply be inserted into the optical path. Typically, the corrective device114may be placed such that it does not physically contact the support structure16or the objective92. FIG.13is another exemplary compensator110design, incorporating a correction collar116in accordance with the present invention. In the illustrated embodiment, the correction collar116may be adjusted between binary states. For instance, the first state118may correspond to the situation where the objective92is focused on and detecting images from the second surface20of the support structure16while the second state120may correspond to the situation where the objective92is focused on and detecting images from the first surface of the support structure16. As such, when the correction collar116is in the first state118, the imaging optics within the objective92may not include the corrective optics within the optical path. Conversely, when the correction collar116is in the second state120, the imaging optics within the objective92may include the corrective optics within the optical path. Although illustrated as consisting of binary states118,120, the correction collar116may, in fact, include multiple states. For instance, when more than two surfaces of the support structure16are used for imaging, the correction collar116may be configured to adjust between multiple states such that the imaging and corrective optics vary for each respective surface of the support structure16. An advantage of the embodiment illustrated inFIG.13is that it may be relatively easy to operate. For instance, the correction collar116may simply be adjusted between states whenever different surfaces of the support structure16are being imaged. FIG.14is another exemplary compensator110design, incorporating an infinite space compensator122in accordance with the present invention. This embodiment is somewhat similar to the corrective device114embodiment ofFIG.12in that the infinite space compensator122may be inserted into and removed from the optical path. However, a main difference between the embodiments is that, in the embodiment ofFIG.14, there may be more space available (e.g., up to 10 mm, as opposed to 600 microns in the embodiment ofFIG.12) within which to insert the infinite space compensator122into the optical path. Therefore, the embodiment ofFIG.14may allow for greater flexibility than the corrective device114embodiment ofFIG.12. In addition to the embodiments presented inFIGS.11through14, there may be other compensator110designs which may prove beneficial. For instance, a fluidic corrector may be inserted between the objective92and the support structure16. In this fluidic corrector design, the fluidic corrector may be filled with a fluid, which may effectively act as the compensator110. The optics may be configured such that the fluid matches the upper surface of the support structure16and, in the absence of fluid air, matches the bottom surface of support structure16. This design may prove beneficial in that it may make automation easier since the fluid would simply be inserted into and extracted from the fluidic corrector depending on which surface is imaged. Regardless of the particular embodiment selected, all of the embodiments disclosed herein are characterized by repeatability and the ability to automate the use of the embodiments. These are important considerations in that the embodiments allow for the detection of images from biological components12,14on multiple surfaces18,20of the support structure16in an automated fashion. This may allow not only for increased imaging production but may also allow for greater flexibility in switching between the multiple surfaces, depending on the particular imaging needs. As described in greater detail above, a support structure16useful in the apparatus or methods set forth herein can have two or more surfaces upon which a biological component is attached. In particular embodiments, the surface is a fabricated surface. Any of a variety of surfaces known in the art can be used including, but not limited to, those used for making arrays as set forth above. Examples include, glass, silicon, polymeric structures, plastics, and the like. Surfaces and flow cells that are particularly useful are described in PCT Publication No. WO 2007/123744, which is incorporated herein by reference. The surfaces of a support structure can have the same or different properties. For example, in the embodiment shown inFIG.3, plate42can be transparent to the excitation and emission wavelengths used in a detection method, whereas plate44can optionally be transparent or opaque to the excitation or emission wavelengths. Accordingly, the surfaces can be made of the same material or the two or more surfaces can be made of different materials. A support structure having two or more surfaces can be formed by adhering the surfaces to each other or to other supports. For example, an adhesive material, such as epoxy resin, can be dispensed in the form of a paste onto a planar substrate in a pattern forming one or more channel characteristics of a flow cell. An exemplary flow cell124is shown inFIG.15. Utilizing a programmable, automated adhesive dispenser, such as the Millennium® M-2010 from Asymtek Corp., Carlsbad Calif., a desired pattern of adhesive126can be designed and laid down onto the surface of a planar lower substrate128. The thickness of the flow cell (and cross sectional height in the fluidic channels) can be set by means of precision mechanical spacers130placed between the lower substrate128and an upper substrate132. Another exemplary flow cell134is shown inFIG.16. To create a multi-layer cell, an interim transparent substrate layer136, shorter in length than the lower and upper substrate layers128,132can be included. The shorter length allows fluidic access to both/all layers from ports138passing through only one substrate. This intermediate layer136bifurcates the flow cell cavity horizontally and nearly doubles the available surface area for the attachment of biologically interesting molecules. An exemplary method140for fabricating such a flow cell is shown inFIG.17. A planar substrate acting as the structural base of the cell is provided (block142). Desired canalizing features of the cell are designed, for example, using a computer assisted design program (block144). A pattern designed in this way can be exported to a file compatible with driving an automatic adhesive dispensing system (block146). A program can be executed to dispense the adhesive in the desired pattern onto the substrate (block148). Precision mechanical spacers can be placed onto the base substrate before or after the adhesive is dispensed (block150). A second transparent substrate can then be placed onto the adhesive pattern, pressing downward until the lower surface is in full contact with the mechanical spacers (block152). A weight or other force is applied to the top substrate to hold it in full contact with the adhesive. The spacers will typically have a height that is equivalent or slightly less than the height of the adhesive layer such that bonding can occur without causing undesirable aberrations in the shape of the canalized features. The steps for adhering substrates may be repeated for any number of layers desired. Optionally, the assembly can be heat treated, for example, in an oven or exposed to UV light, depending upon the cure requirements of the adhesive (block154). Another exemplary method for fabricating a flow cell is to use an intermediate layer that is cut to a desired pattern in place of an adhesive layer. A particularly useful material for the intermediate layer is silicone. The silicone layer can be heat bonded to the lower substrate128and upper substrate132. Exemplary methods utilizing Bisco Silicone HT 6135 as an intermediate layer are described, for example, in Grover et al., Sensors and Actuators B 89:315-323 (2003). Still further,FIG.18illustrates an embodiment utilizing one radiation source and dual detectors. Radiation from the radiation source22is directed by the directing optics30toward the focusing optics32. From the focusing optics32, the excitation radiation58irradiates a biological component12on a first surface18of the support structure16. The biological component12emits a fluorescent emission60back through the focusing optics32toward the directing optics30. This retrobeam is allowed to pass through the directing optics30to the detection optics34which, in this illustrated embodiment, may include a wavelength filter156or some other device for separating the retrobeam, and first and second color filters158,160for achieving multiple color channels. The wavelength filter156may split the retrobeam into two beams with one beam directed toward the first detector36via the first color filter158and the other beam directed toward a second detector162via the second color filter160. In this manner, the biological sample imaging system10may sequentially scan the first and second surfaces18,20, first scanning the first surface18of the support structure16using the first excitation radiation58from the radiation source22and the returned first fluorescent emission60(as depicted in the left portion ofFIG.18), and next scanning the second surface20of the support structure16using the second excitation radiation62from the same radiation source22and the returned second fluorescent emission64(as depicted in the right portion ofFIG.18). Alternatively,FIG.19illustrates an embodiment utilizing dual radiation sources and dual detectors. Again, the two surfaces18,20of the support structure16may be scanned sequentially. However, in this embodiment, the first surface18of the support structure16is first scanned using the first radiation source22which generates the first excitation radiation58and the first fluorescent emission60(as depicted in the left portion ofFIG.19) and, the second surface20of the support structure16is scanned using the second radiation source24which generates the second excitation radiation62and the second fluorescent emission64(as depicted in the right portion ofFIG.19). This embodiment may also be extended to use any number of detectors in order to reduce movement of the filters. In the embodiments described above where scanning of the first and second surfaces18,20of the support structure16may be performed sequentially, the individual steps of scanning the first and second surfaces18,20of the support structure16may be performed in a number of ways. For instance, it may be possible to scan a single line of the first surface18, then scan a single line of the second surface20, then gradually move the first and second surfaces18,20relative to the excitation radiation58,62by translating the support structure16, the directing optics30, the focusing optics32, or some combination thereof, in order to repeat these steps of scanning individual lines. Alternatively, entire regions of the first surface18may be scanned before regions of the second surface20are scanned. The individual processing steps taken may depend upon several variables including the particular configuration of the biological component sites12,14on the surfaces18,20as well as other variables, including environmental and operating conditions. Particular embodiments may allow for simultaneous excitation of multiple surfaces of the support structure16. For instance,FIG.20illustrates an embodiment utilizing dual radiation sources and dual detectors. However, in this embodiment, the first surface18and the second surface20of the support structure16may be simultaneously scanned. This may be accomplished using focusing lenses164,166,168,170and a dichroic mirror172along the excitation path in order to switch surfaces and filters158,160to achieve multiple color channels. Again, this illustrated embodiment may also be extended to any number of detectors to improve throughput, scanning efficiency, and to reduce movement of the filters and other system components. FIG.21illustrates another embodiment utilizing dual radiation sources and dual detectors which allows for simultaneous scanning of the first and second surfaces18,20of the support structure16. In this illustrated embodiment, however, not only are focusing lenses164,166,168,170and a dichroic mirror172used in the excitation path but focusing lenses174,176may be used just upstream of the first and second detectors36,162in conjunction with the filters158,160along the emission path in order to switch surfaces and achieve multiple color channels. Once again, this illustrated embodiment may also be extended to use any number of detectors to increase throughput and scanning efficiency. For instance,FIG.22illustrates an embodiment utilizing multiple radiation sources and multiple detectors which are capable of simultaneously outputting multiple channels with few moving parts. In the illustrated embodiment, radiation sources22and24have been replaced by radiation source groups178and180which are capable of outputting multiple radiation sources and varying wavelengths. In addition, detectors36and38have been replaced by detector groups182and184in the illustrated embodiment. These detector groups182,184are similarly capable of detecting multiple color channels. This embodiment therefore illustrates the considerable adaptability of the present techniques to a range of configurations capable of imaging components on multiple surfaces of the support. In the embodiments described above where scanning of the first and second surfaces18,20of the support structure16may be performed simultaneously, focusing of the excitation radiation58source may be accomplished in several various ways. For instance, it may be possible to focus the excitation radiation58on one of the surfaces preferentially over the other surface. In fact, due to the nature of the configuration of the first surface18with respect to the second surface20, it may be necessary to do so. However, alternate focusing techniques may be employed depending on the specific configuration of the support structure16. Moreover, it may be advantageous in these various configurations to first image the upper surface (i.e., the surface closer to the radiation source) in order to reduce photobleaching of the components on that surface that could result from first imaging the lower surface (i.e., the surface farther from the radiation source). Such selection of which surface to image may apply both when the surfaces are imaged sequentially as well as when they are imaged simultaneously. In addition, the embodiments disclosed above have illustrated an epifluorescent imaging scheme wherein the excitation radiation is directed toward the surfaces of the support structure16from a top side, and returned fluorescent radiation is received from the same side. However, the techniques of the present invention may also be extended to alternate arrangements. For instance, these techniques may also be employed in conjunction with TIR imaging whereby the surfaces of the support structure are irradiated from a lateral side with radiation directed at an incident angle within a range of critical angles so as to convey the excitation radiation within the support or into the support from a prism positioned adjacent to it. TIR techniques can be carried out as described, for example, in U.S. Patent Application Publication No. 2005/0057798, which is hereby incorporated by reference. Such techniques cause fluorescent emissions from the components that are conveyed outwardly for imaging, while the reflected excitation radiation exits via a side opposite from that through which it entered. Here again, biological components on the multiple surfaces may be imaged sequentially or simultaneously. For example, inFIG.23, a TIR biological sample imaging system186is illustrated diagrammatically. A support structure188may be used which includes multiple flow lanes190containing biological components. For example, the support structure188may be a flow cell through which reagents, flushes, and other fluids may be introduced using the flow lanes190to contact emissive components attached to the surface of the flow cell. The support structure188may be supported by a prism192. In the TIR biological sample imaging system186, the radiation source194may output a radiation beam196through the prism192from a lateral side of the support structure188. The radiation beam196may, for instance, be directed toward a bottom surface of one of the flow lanes190of the support structure188, thereby exciting emissive components attached to the surface. As discussed in further detail below, as long as the incident angle of the radiation beam196is within the range of critical angles (as described, for example, in US 2005/0057798), a portion of the radiation beam196will be reflected off the bottom surface whereas a separate fluorescent emission beam from surface-bound emissive components will be directed toward focusing optics198. Typically, a well collimated radiation beam is used to prevent spread of angles within the beam, thereby preventing unwanted hindrance of total internal reflectance. The fluorescent emission beam may propagate back through the focusing optics198, directing optics200, and detection optics202which may direct the beam toward a detector204. The focusing optics198, directing optics200, detection optics202, and detector204may operate in much the same manner as with the epifluorescent techniques discussed above. In the TIR biological sample imaging system186, the focusing light source206may be used as a separate light source from the radiation source194to focus the optics on a particular surface to be imaged. For instance, the focusing light source206may be directed to the directing optics200where it is redirected toward the focusing optics198which are used to focus the system on a particular surface of the support structure188. The TIR biological sample imaging system186may also include a translation system208for moving the support structure188and prism192in one or more dimensions. The translation system208may be used with focusing, redirecting the radiation source194to different areas of the support structure188, as well as for moving the support structure188and prism192to a heating/cooling station210. The heating/cooling station210may be used to heat and cool the support structure188before and after imaging. In addition, a control/processing system212may be used to control operation of the radiation source194, the focusing light source206, and the heating/cooling station210, movement and focusing of the focusing optics198, the translation system208, and the detection optics202, and acquisition and processing of signals from the detector204. As discussed above, the TIR method of imaging may be used to direct the radiation beam196from a lateral side of the support structure188, as illustrated inFIG.24. Each flow lane190of the support structure188may include a bottom surface214and a top surface216and emissive components can optionally be attached to either or both surface. In the illustrated embodiment, the radiation beam196is directed toward a bottom surface214of one of the flow lanes190of the support structure188. Part of the radiation beam196may be reflected off the bottom surface214of the flow lane190, as depicted by reflected light beam218. However, as long as the incident angle of the radiation beam196is within the range of critical angles, a separate fluorescent emission beam220may be emitted from emissive components toward the focusing optics198which in the illustrated embodiment is a lens objective222. Indeed, directing the radiation beam196at a bottom surface214of a flow lane190of the support structure188is a typical implementation of the TIR imaging method. However, in doing so, imaging data which may be collected from a top surface216of a flow lane190of the support structure188may be overlooked. Therefore, the orientation of the radiation source194and/or the support structure188and prism192may be adjusted in order to allow the radiation beam196to not be directed at a bottom surface214of a flow lane190of the support structure188, as illustrated inFIG.25. In the illustrated embodiment, the radiation beam196is oriented so that the radiation beam196passes through the prism192and support structure188until contacting an air/glass interface224of the support structure188at which point the radiation beam196is redirected toward a top surface216of a flow lane190of the support structure188. At this point, part of the radiation beam196may be reflected back toward another air/glass interface224of the support structure188. However, a separate fluorescent emission beam220may be emitted from an emissive component on the top surface216toward the lens objective222. Using this technique, top surfaces216of the flow lanes190of the support structure188may be imaged using TIR imaging methods. This, in effect, may allow for double the imaging data output for cluster based sequencing applications while keeping other variables, such as surface coating, cluster creation, and sequencing, the same. In order to accomplish this TIR imaging of top surfaces216of the flow lanes190of the support structure188, the radiation beam196reaches the air/glass interface224of the support structure188unperturbed. To do so, the radiation beam196does not first come into contact with emissive components in adjacent flow lanes190. To do so, either the radiation beam196may be directed around the adjacent flow lanes190or the adjacent flow lanes190may be index matched with the support structure188material. In some embodiments, the flow lanes190may be spaced within the support structure188, leaving sufficient room between the flow lanes190for the radiation beam196to pass. However, spacing the flow lanes190in this manner may ultimately reduce the amount of emissive components which may be imaged. Therefore, in other embodiments, it may be possible to accomplish the same effect by temporarily filling alternate flow lanes190with index matching fluid. Doing so may allow for easier direction of the radiation beam196toward a top surface216of a flow lane190of the support structure188. It may also be possible to direct the radiation beam196in such a way that it bounces off multiple top surfaces216of flow lanes190of the support structure188, as illustrated inFIG.26. In order to accomplish this, the spacing of the flow lanes190can be matched with the angle of radiation beam196such that the radiation beam196is able to pass by the flow lanes190, such that it reaches the air/glass interface224of the support structure188unperturbed, while also being able to bounce back and forth between top surfaces216of flow lanes190and the air/glass interface224of the support structure188. As described above, in certain embodiments, some of the flow lanes190may be filled with an index matching fluid, such that these index-matched flow lanes190effectively become “invisible” to the radiation beam196. In other words, the radiation beam196may be allowed to pass through the index-matched flow lanes190. By allowing the radiation beam196to pass through the index-matched flow lanes190, the support structure188may be used in multiple configurations without the need of varying the spacing of the flow lanes190. In some embodiments, mirrors226or other suitable reflective material may be used within certain flow lanes190, facilitating this multi-bounce technique. In any event, assuming N number of flow lanes190, it may only be possible to image N-2 number of top surfaces216of the flow lanes190in this manner due to the fact that the outer flow lanes190on either side of the support structure188may not be accessible using these techniques. However, modification of the prism192and/or support structure188may allow for imaging of the top surfaces216of these outermost flow lanes190. For instance, the support structure188may be designed to fit within the prism192, allowing the radiation beam196to propagate into a lateral side of the support structure188. In some embodiments, as discussed above briefly with respect toFIG.23, the support structure188may be moved to a heating/cooling station210, for example, by the action of the translation system208. The heating/cooling station210may be configured to both heat and cool the support structure188before and after imaging. The heating/cooling station210may, in fact, be configured to heat and cool both a top surface228and a bottom surface230of the support structure188, as illustrated inFIG.27. Indeed, all surfaces of the support structure188may be heated or cooled at the heating/cooling station210. In this manner, it may further be possible to heat and cool both the top surfaces216and bottom surfaces214of the flow lanes190of the support structure188by directly contacting one or more surfaces of the flow cell with a heating or cooling device. This, of course, may facilitate the development of biological components within the flow lanes190of the support structure188and, therefore, facilitate imaging. Although use of the heating/cooling station210has been presented herein with respect to the TIR imaging methods, the heating/cooling station210may also be used to heat and cool multiple sides of a support structure used in conjunction with the epifluorescent imaging methods discussed herein. In particular embodiments, the current invention utilizes sequencing-by-synthesis (SBS). In SBS, four fluorescently labeled modified nucleotides are used to determine the sequence of nucleotides for nucleic acids present on the surface of a support structure such as a flow cell. Exemplary SBS systems and methods which can be utilized with the apparatus and methods set forth herein are described in U.S. Pat. No. 7,057,026; U.S. Patent Application Publication Nos. 2005/0100900, 2006/0188901, 2006/0240439, 2006/0281109, and 2007/0166705; and PCT Publication Nos. WO 05/065814, WO 06/064199, and WO 07/010251; each of which is incorporated herein by reference. In particular uses of the apparatus and methods herein, flow cells containing arrayed nucleic acids are treated by several repeated cycles of an overall sequencing process. The nucleic acids are prepared such that they include an oligonucleotide primer adjacent to an unknown target sequence. To initiate the first SBS sequencing cycle, one or more differently labeled nucleotides and a DNA polymerase are flowed into the flow cell. Either a single nucleotide can be added at a time, or the nucleotides used in the sequencing procedure can be specially designed to possess a reversible termination property, thus allowing each cycle of the sequencing reaction to occur simultaneously in the presence of all four labeled nucleotides (A, C, T, G). Following nucleotide addition, the features on the surface can be imaged to determine the identity of the incorporated nucleotide (based on the labels on the nucleotides). Then, reagents can be added to the flow cell to remove the blocked 3′ terminus (if appropriate) and to remove labels from each incorporated base. Such cycles are then repeated and the sequence of each cluster is read over the multiple chemistry cycles. Other sequencing methods that use cyclic reactions wherein each cycle includes steps of delivering one or more reagents to nucleic acids on a surface and imaging the surface bound nucleic acids can also be used such as pyrosequencing and sequencing by ligation. Useful pyrosequencing reactions are described, for example, in U.S. Pat. No. 7,244,559 and U.S. Patent Application Publication No. 2005/0191698, each of which is incorporated herein by reference. Sequencing by ligation reactions are described, for example, in Shendure et al. Science 309:1728-1732 (2005); and U.S. Pat. Nos. 5,599,675 and 5,750,341, each of which is incorporated herein by reference. The methods and apparatus described herein are also useful for detection of features occurring on surfaces used in genotyping assays, expression analyses and other assays known in the art such as those described in U.S. Patent Application Publication Nos. 2003/0108900, 2003/0215821, and US 2005/0181394, each of which is incorporated herein by reference. While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. | 69,449 |
RE49885 | DESCRIPTION OF EXEMPLARY EMBODIMENTS First Embodiment Hereinafter, a polarization device and a method of manufacturing the polarization device according to an embodiment of the invention will be described with reference to the drawings.FIGS.1A and1Bare schematic diagrams of a polarization device1A of this embodiment, in whichFIG.1Ais a partial perspective view andFIG.1Bis a partial cross-sectional view, in which the polarization device1A is cut out at the YZ plane. In addition, in the following description, the orthogonal XYZ coordinate system is set and a positional relationship of each member will be described with reference to the XYZ coordinate system. At this time, a plane, which is parallel to a plane11c of a substrate11provided with a metal layer12, is set as the XY plane, and an extending direction of the metal layer12is set as the X-axis direction. An arrangement axis of the metal layer12is the Y-axis. In addition, in all of the following drawings, the scale and thickness of each component is appropriately made to be different for easy understanding of the drawings. Polarization Device As shown inFIGS.1A and1B, the polarization device1A includes a substrate11, a plurality of metal layers12formed on the substrate11in a stripe shape in a plan view, first dielectric layers13, each covering one of the metal layers12, and second dielectric layers14, each being provided on each of the first dielectric layers13. The first dielectric layer13covers a first side face12a extending in an X-axis direction of the metal layer12, a second side face12b opposite to the first side face12a, and a top part12c. As the substrate11, a glass substrate is used. However, the substrate11may be formed of a translucent material. For example, quartz, plastic, or the like may be used for the substrate. In addition, since the polarization device1A may accumulate heat and gain a high temperature depending on a usage of the polarization device1A, as the material of the substrate11, glass or quartz having high heat resistance is preferable. As a material of the metal layer12, a material having a high reflectance with respect to light in a visible range is used. In this embodiment, as the material of the metal layer12, aluminum is used. A metallic material such as silver, copper, chrome, titanium, nickel, tungsten, and iron may be used other than aluminum. The first dielectric layer13is formed on the first side face12a, the second side face12b, and the top part12c of the metal layer12. As a material of the first dielectric layer13, a material having a high translucency in a visible range, for example, a dielectric material such as aluminum oxide is used. In this example, as the first dielectric layer13, an oxide of the metal layer12is used. As described later, the first dielectric layer13may be formed by oxidizing the metal layer12. A groove portion15is provided between two adjacent metal layers12. The groove portion15is provided with a substantially equal distance in the Y-axis direction at a cycle shorter than a wavelength of visible light. The metal layer12and the first dielectric layer13are arranged in the Y-axis direction with the same cycle as each other. For example, a height H1of the metal layer12is50to200nm, and a width L1of the metal layer12in the Y-axis direction is40nm. A height H2of the first dielectric layer13is10to100nm, and a width L2of the first dielectric layer13in the Y-axis direction is5to30nm. The width L2of the first dielectric layer13may be called a thickness of the first dielectric layer13at a side face of the metal layer12. In addition, a distance S between two adjacent first dielectric layers13(width of the groove portion15in the Y-axis direction) is70nm, and a cycle P (pitch) is140nm. The second dielectric layer14is provided on the first dielectric layer13in regard to the first side face12a, the second side face12b, and the top part12c of the metal layer12. That is, the first dielectric layer13is provided between the second dielectric layer14and the metal layer12. In addition, the second dielectric layer14extends in the X-axis direction similar to the metal layer12. As a material of the second dielectric layer14, a material having an optical absorption rate higher than that of the first dielectric layer13in a visible range is used. In this embodiment, germanium is used. Other than germanium, for example, silicon, molybdenum, tellurium, or the like may be used. In addition, in the YZ cross-section shown inFIG.1B, a width L3of the second dielectric layer14in the Y-axis direction has a value that is larger than double the sum of the width L1of the metal layer12and the width L2of the first dielectric layer13and that is smaller than the cycle P (pitch) of the first dielectric layer13(or the metal layer12). The second dielectric layer14includes a first member14a formed at the side of the first side face12a of the metal layer12, that is, on a first side face13a of the first dielectric layer13and a second member14b formed at the side of the second side face12b of the metal layer12, that is, on a second side face13b of the first dielectric layer13, and the first and second members14a and14b overlap each other at the top part12c (upper end) of the metal layer12. Suppose that a second dielectric layer14K which is provided to a metal layer12K and a second dielectric layer14M which is provided to a metal layer12other than the metal layer12K are selected. If a cross-sectional area of a first member14aK making up the second dielectric layer14K in a YZ cross-section and a cross-sectional area of a first member14aM making up the second dielectric layer14M in the YZ cross-section are compared to each other, the cross-sectional area of the first member14aK is different from the cross-sectional area of the first member14aM. Similarly, a cross-sectional area of a second member14bK making up the second dielectric layer14K is different from a cross-sectional area of a second member14bM making up the second dielectric layer14M. The above-described difference in the cross-sectional area corresponds to the difference in a volume per unit length. Here, a definition of the volume per unit length of the first member14a will be described by using a metal layer12K. In the first members14aK provided corresponding to the metal layer12K, a value obtained by dividing a volume of the first member14aK in a region where the metal layer12K and the first member14aK are commonly provided in the X-axis direction by a length of the region in the X-axis direction is defined as the volume per unit length of the first member14aK. A volume per unit length of the second member14b and a volume per unit length of the second dielectric layer14are also defined in a similar way. Hereinafter, in this specification, the volume per unit length is referred to as a volume for simplicity. Specifically, the volume of the first member14a and the volume of the second member14b depend on a distance from a first end11a of the substrate11in the Y-axis direction. More specifically, the volume of the first member14a becomes large as it approaches the first end11a, and the volume of the second member14b becomes large as it approaches a second end11b opposite to the first end11a. In addition, in the metal layer12that is closest to the first end11a, the volume of the first member14a making up the second dielectric layer14is larger than the volume of the second member14b making up the second dielectric layer14, and in the metal layer12that is the most distant from the first end11a, the volume of the first member14a making up the second dielectric layer14is smaller than the volume of the second member14b making up the second dielectric layer14. However, the volume of the second dielectric layer14represented by the sum of the volume of the first member14a and the volume of the second member14b has approximately a constant value in any second dielectric layer14. That is, as shown inFIG.1B, the volume of the first member14aK is different from the volume of the second member14bK, the volume of the first member14aL is different from the volume of the second member14bL, and the volume of the first member14aM is different from the volume of the second member14bM, but the volume of the second dielectric layer14K, the volume of the second dielectric layer14L, and the volume of the second dielectric layer14M are approximately the same as each other. A relationship between the volume of the first member14a, the volume of the second member14b, and the volume of the second dielectric layer14is also true of a relationship of a cross-sectional area of the first member14a, a cross-sectional area of the second member14b, and the cross-sectional area of the second dielectric layer14represented by the sum of the cross-sectional area of the first member14a and the cross-sectional area of the second member14b, in the YZ cross-section. In addition, in regard toFIG.1A, the dependency on the distance from the first end11a in the volume of the first member14a and the volume of the second member14b, is drawn exaggeratedly. As described above, the polarization device1A including the metal layer12, the first dielectric layer13, and the second dielectric layer14is configured to transmit a transverse magnetic (TM) wave21that is linearly polarized light vibrating in a direction (Y-axis direction) orthogonal to the extension direction of the metal layer12and to absorb a transverse electric (TE) wave22that is linearly polarized light vibrating in the extension direction (X-axis direction) of the metal layer12. Method of Manufacturing Polarization Device Hereinafter, a method of manufacturing the polarization device1A of this embodiment will be described.FIGS.2A to2Dshow process diagrams illustrating a method of manufacturing the polarization device in the first embodiment. The method of manufacturing the polarization device1A according to this embodiment includes a metal layer forming process of forming the plurality of metal layers12with a stripe shape in a plan view on the substrate11, a first dielectric layer forming process of forming the first dielectric layer13on the first side face12a, the second side face12b, and the top part12c of the metal layer12, and a second dielectric layer forming process of forming the second dielectric layer14(the first and second members14a and14b) on the first side face13a, the second side face13b, and the top part13c (upper end) of the first dielectric layer13, that is, a side of the first dielectric layer13, which is opposite to the metal layer12. Furthermore, the process of forming the second dielectric layer includes a first member forming process of obliquely forming a film from a direction from one of two first dielectric layers13adjacent to each other to form a first member14a on the top part and a side face of the first dielectric layer13, and a second member forming process of obliquely forming a film from a direction from the other of the first dielectric layers13to form the second member14b as an upper layer of the first dielectric layer13. Hereinafter, description will be given with reference to the drawings. In the process of forming the metal layer ofFIG.2A, the metal layer12is formed on a plane11c of the substrate11. Specifically, an aluminum film is formed on the substrate and a resist film is formed on the aluminum film. Subsequently, the resist film is exposed and then is developed, and thereby a stripe-shaped pattern is formed in the resist film. Subsequently, the aluminum film is etched until the plane11c of the substrate11comes to appear by using the resist film as an etching mask. Subsequently, the resist film is removed, and thereby a plurality of metal layers12disposed in a stripe shape is formed on the substrate11. In the first dielectric layer forming process ofFIG.2B, the first dielectric layer13is formed on the first side face12a, the second side face12b, and the top part12c of each of the metal layers12. Specifically, the substrate11on which the metal layers12are formed is disposed in a vacuum vessel that is formed of quartz or the like and ozone gas is controlled within a range of50Pa to100Pa therein. Subsequently, the metal layers12are irradiated by ultraviolet light (wavelength<310nm) from the plane11c side of the substrate11. The ultraviolet light is emitted by a Deep-UV lamp. For example, an intensity of the ultraviolet light is120mW/cm2. The ozone gas has a high absorption coefficient within a wavelength of220nm to300nm, such that as a result of optical absorption reaction, oxygen atoms in an excited state, which has high energy, may be generated efficiently. The excited oxygen atoms have a diffusion coefficient (activity) greater than that of normal oxygen atoms have, and show a high oxidation rate. In addition, an oxidized film may be formed at a low temperature lower than that in thermal oxidation. In this process, a side, which is opposite to the plane11c of the substrate11, is irradiated by a halogen lamp and thereby a temperature of the substrate is increased to150° C. Accordingly, the oxidation reaction is further promoted. Under this environment, ozone oxidation is performed for20minutes, and thereby an aluminum oxidized film (first dielectric layer13) with a thickness L2of30nm is formed on a surface of the metal layer12. The thickness of the first dielectric layer may be appropriately selected depending on a magnitude of a phase difference applied to visible light. According to the manufacturing method of this embodiment, it is possible to form the oxidized film (first dielectric layer13) of the metal layer12at a temperature lower than that in the related art. Therefore, it is possible to decrease cracking or deformation of the substrate, and it is possible to decrease variation before and after the heat treatment in the dimensions of the metal layer12such as the height and the width that determine the characteristics of the polarization device. Therefore, it is possible to increase an in-plane uniformity of the polarization characteristics of the polarization device1A. In addition, according to the manufacturing method of this embodiment, it is possible to cover the first side face12a, the second side face12b, and the top part12c of the metal layer12with the first dielectric layer13a density higher than that in the related art. Therefore, even when the temperature is raised in use, it is possible to prevent the deterioration of the metal layer12, which may be caused by oxidation or the like, and thereby it is possible to lower a decrease in the polarization characteristic. In the first member forming process ofFIG.2C, germanium is obliquely deposited to form the first member14a on the first side face13a and the top part13c (upper end) of the first dielectric layer13. Specifically, a sputtered particle20is deposited on the first side face13a and the top part13c (upper end) of the first dielectric layer13in a first direction D1that is oblique with respect to a surface normal line (Z-axis direction) of the plane11c of the surface11on which the metal layer12and the first dielectric layer13are formed and that is opposite to the first side face12a of the metal layer12, for example, by using a sputtering apparatus, to form the first member14a. In addition, inFIGS.2C and2D, a main incident direction of the sputtered particle20is indicated by an arrow. An angle between the surface normal line of the plane11c of the substrate11and the incident direction of the sputtered particle20may be appropriately set within a range of40° to85°. In the second member forming process ofFIG.2D, germanium is obliquely deposited to form the second member14b as an upper layer of the first dielectric layer13. Specifically, a sputtered particle20is deposited on the second side face13b and the first member14a of the first dielectric layer13from a second direction D2that is oblique with respect to the surface normal line of the plane11c of the substrate11and that is opposite to the second side face12b of the metal layer12, for example, by using a sputtering apparatus, to form the second member14b as an upper layer of the first dielectric layer13. An angle between the surface normal line of the plane11c of the substrate11and the incident direction of the sputtered particle20may be appropriately set within a range of40° to85°. As described above, the first and second members14a and14b are formed, whereby it is possible to form the second dielectric layer14. Through the above-described processes, the polarization device1A can be manufactured. In addition, in this embodiment, as the material of the first and second members, germanium is used, but the material of the first member may be different from that of the second member. In this case, it is preferable that the difference in the optical absorption rate between the material of the first member and the second member is small. Here, in the first member forming process, due to a so-called shadowing effect where a part of the metal layer12and a part of the first dielectric layer13are shadowed at the time of obliquely forming a film, the first member is hardly formed at the groove portion15formed between two adjacent metal layers12. Similarly, in the second member forming process, due to the shadowing effect at the time of obliquely forming a film, the second member is hardly formed at the groove portion15. As a method of forming the second dielectric layer on the first dielectric layer, a method in which the material of the second dielectric layer is deposited on the first dielectric layer from a direction (Z-axis direction) that is parallel with the surface normal line of the substrate11may be considered. In this case, the material of the second dielectric layer is also deposited at a region (groove portion15) between the two adjacent metal layers12on the substrate11. However, when the second dielectric layer is formed at the groove portion15, the characteristics of the polarization device1A as a polarization plate is deteriorated, such that it is necessary to remove the second dielectric layer formed at the groove portion15. On the other hand, according to the manufacturing method of this embodiment, it is possible to prevent the second dielectric layer from being formed at the groove portion15, such that a process of removing the second dielectric layer formed at the groove portion15is not necessary. The first member14a is provided on the first side face13a of the first dielectric layer13, but a substrate11side end portion14az of the first member14a is located between the plane11c of the substrate11and the top part13c (upper end) of the first dielectric layer13. That is, the end portion14az of the first member14a is terminated on the face of the first side face13a. Similarly, the second member14b is provided on the second side face13b of the first dielectric layer13, but a substrate11side end portion14bz of the second member14b is located between the plane11c of the substrate11and the top part13c (upper end) of the first dielectric layer13. That is, the end portion14bz of the second member14b is terminated on the face of the second side face13b. As described above, neither the first member14a nor the second member14b are provided at the groove portion15. As shown inFIG.1B, a cross-section of the second dielectric layer14in a YZ cross-section has a shape where a portion having the greatest width L3in the second dielectric layer14is located at the top part side of the second dielectric layer14rather than the substrate11side end portion14az of the first member14a and the substrate11side end portion14bz of the second member14b. In addition, at the time of obliquely forming a film in the above-described first member forming process and the second member forming process, there is a tendency that an amount of the sputtered particles to be deposited between a region close to a target of the sputtering apparatus and a region far away from the target is different in the plane11c of the substrate11. Specifically, as it is close to the target, the amount of the sputtered particles to be deposited becomes large. Therefore, in the first member forming process ofFIG.2C, a volume of the first member14a becomes large as it approaches the target of the sputtering apparatus (a positive direction side of the Y-axis) and becomes small as it moves away from the target (a negative direction side of the Y-axis). On the other hand, in the second member forming process ofFIG.2D, a volume of the second member14b becomes large as it approaches the target of the sputtering apparatus (the negative direction side of the Y-axis) and becomes small as it moves away from the target (the positive direction side of the Y-axis). Therefore, as described above with reference toFIG.1B, the volume of the first member14aK is different from that of the second member14bK, the volume of the first member14aL is different from that of the second member14bL, and the volume of the first member14aM is different from that of the second member14bM, but the volumes of the second dielectric layer14K, the second dielectric layer14L, and the second dielectric layer14M are approximately equal each other. That is, the second dielectric layer14having approximately the same volume is formed on the metal layers12, respectively. Hereinafter, an operation of the polarization device1A of this embodiment will be described. As described above, in regard to the polarization device1A, the metal layer12is formed of a material such as aluminum that has a high optical reflectance within a visible region. In addition, the first dielectric layer13is formed of a material such as aluminum oxide that has a high optical transmittance in a visible region. Furthermore, the second dielectric layer14(the first and second members14a and14b) is formed of a material such as germanium that has an optical absorption rate higher than that of the first dielectric layer13in a visible region. As described above, the polarization device1A has a structure where the metal layer12and the first and second dielectric layers13and14are laminated, such that it is possible to transmit the TM wave21that is linearly polarized light vibrating in a direction orthogonal to the extension direction of the metal layer and to absorb the TE wave22that is linearly polarized light vibrating in the extension direction of the metal layer. That is to say, the TE wave22incident from the second dielectric layer14side of the substrate11is attenuated by an optical absorption effect of the second dielectric layer14, and when apart of the TE wave22passes through the second dielectric layer14and the first dielectric layer13without being absorbed, a phase difference is applied thereto. The TE wave22passed through the first dielectric layer13is reflected from the metal layer12(functions as a wire grid). When the reflected TE wave22passes through the first dielectric layer13, a phase difference is applied thereto, and the reflected TE wave22is attenuated by an interference effect and a remainder thereof is absorbed again by the second dielectric layer14. Therefore, due to the above-described attenuation effect of the TE wave22, it is possible to obtain a desired absorption type polarization characteristic. In a case where the material of the second dielectric layer14is deposited on the first dielectric layer13from a direction oblique with respect to the Z-axis direction for preventing the second dielectric layer14from being formed in the groove portion15, an amount of deposition of the material of the second dielectric layer14becomes different depending on the distance from a target. Therefore, the attenuation effect of the TE wave22may become non-uniform in a plane of the substrate11, but according to the manufacturing method of this embodiment, it is possible to form the first and second members14a and14b formed of the same material on the metal layers12, respectively, in a manner that the volume of the second dielectric layer14provided to each of the metal layer12is approximately the same with each other, such that it is possible to increase in-plane uniformity of the substrate11in the attenuation effect of the TE wave22. As a result thereof, it is possible to increase in-plane uniformity of the polarization characteristic in the absorption type polarization device. In addition, the entirety of both side faces and top face of the metal layer12is covered by the first dielectric layer13with a density higher than that in the related art, such that the deterioration of the metal layer, which may be caused by oxidation or the like, is prevented, and thereby it is possible to prevent the decrease in a polarization separation function. Since an area of remaining side face of the metal layer12is extremely small compared to the total surface area of the metal layer12, the remaining side face of the metal layer12is not necessary to be covered by the first dielectric layer13, but it may be covered. As described above, according to this embodiment, it is possible to obtain the polarization device1A in which the in-plane uniformity of the polarization characteristic is high, and the polarization characteristic is not easily decreased even when a temperature is raised in use. Modified Example of First Embodiment FIG.3shows an explanatory diagram of a polarization device1B according to a modified example of the first embodiment. The polarization device1B is partially common to the polarization device1A of the first embodiment. There is a difference in that a region16, which has a refraction index lower than that of the substrate11, is formed between the metal layers12. As shown inFIG.3, the polarization device1B has a region16having a refraction index lower than that of the substrate11between two adjacent metal layers12, in addition to the configuration of the polarization device1A. The region16is formed by removing the substrate11exposed between the two adjacent metal layers12through dry etching or the like. A digging depth H3is substantially the same as a height H1of the metal layer12. According to this configuration, it is possible to reduce an effective refraction index of a boundary region between the substrate and the metal layer, such that the reflection of the TM wave21at the boundary region is suppressed and as a result, it is possible to increase the transmittance of the TM wave21. Projection Type Display Apparatus Hereinafter, embodiments of an electronic apparatus according to the invention will be described. A projector800, which is shown inFIG.4, includes a light source810, dichroic mirrors813and814, reflective mirrors815,816, and817, an incident lens818, a relay lens819, an emission lens820, light modulating units822,823, and824, a cross dichroic prism825, and a projective lens826. The light source810includes a lamp811such as a metal halide, and a reflector812that reflects light of the lamp. In addition, as the light source810, an ultrahigh pressure mercury lamp, a flash mercury lamp, a high pressure mercury lamp, a Deep UV lamp, a xenon lamp, a xenon flash lamp or the like may be used other than the metal halide. The dichroic mirror813transmits red light included in white light emitted from the light source810and reflects blue light and green light. The transmitted red light is reflected from the reflective mirror817and is incident to the light modulating unit822for red light. In addition, among the blue light and the green light reflected from the dichroic mirror813, the green light is reflected from the dichroic mirror814and is incident to the light modulating unit823for green light. The blue light passes through the dichroic mirror814and is incident to the light modulating unit824via a relay optical system821including the incident lens818that is provided to prevent light loss caused by a long optical path, the relay lens819, and the emission lens820. In the light modulating units822to824, an incident side polarization device840and an emission side polarization device section850are disposed with a liquid crystal light valve830interposed therebetween. The incident side polarization device840is provided on a light path of light emitted from the light source810and between the light source810and the liquid crystal light valve830. In addition, the emission side polarization device section850is provided on a light path of light passed through the liquid crystal light valve830and between the liquid crystal light valve830and the projection lens826. The incident side polarization device840and the emission side polarization device section850are disposed in a manner that transmission axes thereof are orthogonal to each other (cross-Nicole arrangement). The incident side polarization device840is a reflection type polarization device described in the first embodiment and reflects light in a vibration direction orthogonal to the transmission axis. On the other hand, the emission side polarization device section850includes a first polarization device (pre-polarization plate, synonymous with a pre-polarizer)852, and a second polarization device854. As the first polarization device852, the above-described polarization device of the second embodiment of the invention, which is provided with a protective film and has a high heat resistance, is used. In addition, the second polarization device854is a polarization device formed of an organic material as a formation material. The first and second polarization devices852and854are absorption type polarization devices, respectively, and the first and second polarization devices852and854absorb light in cooperation with each other. In addition, as the first polarization device852, the polarization device according to the first embodiment of the invention may be used. In addition, as the incident side polarization device840, the polarization device according to the invention may be used. In general, an absorption type polarization device, which is formed of an organic material, is apt to be deteriorated due to heat, such that it is difficult to be used as a polarization device of a large output projector in which high brightness is necessary. However, in the projector800according to the invention, the first polarization device852, which is formed of an inorganic material having high heat resistance, is disposed between the second polarization device854and the liquid crystal light valve830, and the first and second polarization devices852and854absorb light in cooperation with each other. Therefore, it is possible to suppress the deterioration of the second polarization device854formed of an organic material. Three colored light beams modulated by respective light modulating units822to824are incident to a cross dichroic prism825. The cross dichroic prism825includes four right angle prisms bonded to each other, and at a boundary face thereof, a dielectric multi-layered film reflecting red light and a dielectric multi-layered film reflecting blue light are formed in an X-shape. The three colored light beams are synthesized by these dielectric multi-layered films and light representing a color image is formed. The synthesized light is projected on a screen827by a projection lens826that is a projective optical system and the image is enlarged and displayed. The projector800with the above-described configuration uses the polarization device according to the invention is utilized as the emission side polarization device section850, whereby it is possible to suppress the deterioration of the polarization device even when the high-output light source is used. Therefore, it is possible to provide the projector800that has a high reliability and a superior display characteristic. Liquid Crystal Device FIG.5shows a cross-sectional schematic diagram illustrating an example of a liquid crystal device300including the polarization device according to the invention. The liquid crystal device300of this embodiment has a configuration where a liquid crystal layer350is interposed between an element substrate310and a counter substrate320. The element substrate310includes a polarization device330, and the counter substrate320includes a polarization device340. The polarization device330and the polarization device340are the above-described polarization devices of the first embodiment. The polarization device330includes a substrate main body331, a metal layer332, and a protective film333, and the polarization device340includes a substrate main body341, a metal layer342, and a protective film343. However, the first and second dielectric layers13and14, which include the metal layers332and342, respectively, are not shown inFIG.5. In this embodiment, the substrate main bodies331and341are substrates of the polarization device and also serve as substrates for the liquid crystal device. In addition, the metal layers332and342are disposed to intersect each other. In any of the polarization devices, the metal layer is disposed at an inner face side (liquid crystal layer350side). At the liquid crystal layer350side of the polarization device330, a pixel electrode314, an interconnection and a TFT device (not shown), and an alignment film316are provided. Similarly, at an inner face side of the polarization device340, a common electrode324and an alignment film326are provided. In the liquid crystal device configured as described above, the substrate main bodies331and341combine the functions of the substrate for the liquid crystal device and the substrate for the polarization device, whereby it is possible to reduce the number of parts. Therefore, the entirety of the apparatus can be made to be slim, and thereby the function of the liquid crystal device300can be improved. Furthermore, the apparatus structure is simple, such that the manufacturing thereof is easy and thereby a reduction in cost may be realized. Electronic Apparatus Hereinafter, another embodiment related to an electronic apparatus according to the invention will be described.FIG.6shows a perspective view illustrating an example of the electronic apparatus using the liquid crystal device shown inFIG.5. A mobile phone (electronic apparatus)1300shown inFIG.6includes the liquid crystal device as a small-sized display section1301, a plurality of operation buttons1302, an ear-piece1303, and a mouthpiece1304. Therefore, it is possible to provide the mobile phone1300including a display section that has superior reliability and can display in high quality. In addition, the liquid crystal device may be suitably used as an image display section of an electronic book, a personal computer, a digital still camera, a liquid crystal television, a projector, a view finder type or monitor direct vision type video tape recorder, a car navigation apparatus, a pager, an electronic pocket book, a calculator, a word processor, a work station, a television phone, a POS terminal, an apparatus having a touch panel, or the like, other than the mobile phone. The invention is not limited to the above-described embodiment and various changes may be made without departing from the scope of the invention. Test Production Verification of Polarization Device and Evaluation of Reliability For confirming the effect of the invention, first, a polarization device not including the second dielectric layer was manufactured and characteristics thereof were evaluated. In the evaluation, it was assumed that the polarization device according to the invention was applied as a polarization device for a light valve of a liquid crystal projector. The polarization device according to the invention is formed of an inorganic material and has a high heat resistance, and thereby can be applied as an incident side polarization device of a liquid crystal projector having the high output light source described above. In the incident side polarization device as described above, it is necessary to have high transmittance with respect to TM light, and to have a high reflectance and a low transmittance with respect to TE light. Specifically, when the transmittance I(TM) of TM light is greater than80%, and the transmittance I(TE) of the TE light is less than1%, there is no problem in use, and it is more preferable that the contrast defined by I(TM)/I(TE) is100or more. In addition, a time where the transmittance of the TE light is changed by10% from an initial value is defined as a product lifespan. Test production levels are shown in Table1. A width L2of the first dielectric layer13is controlled by a processing time of the above-described ozone oxidation. In each sample, the following are common. The height H1of aluminum (metal layer12):160nm, the width S of the groove portion15:70nm, and the cycle P of the first dielectric layer13(or metal layer12):140nm. Sample No.1is a comparative example where the ozone processing is not performed, and a naturally oxidized film is formed on a surface of the metal layer12. The naturally oxidized film is different from the first dielectric layer13according to the invention, but in Table1, a thickness of the naturally oxidized film of Sample No.1is shown as a width L2of a first dielectric layer for convenience.FIG.7shows SEM observation results of Nos.2,3, and4. In the observation, in order to measure a width of the dielectric layer, the aluminum was dissolved to expose the first dielectric layer13. TABLE 1Width L1 of metalWidth L2 of firstSample No.layer (mm)dielectric layer (mm)1605240153302041826 With respect to the sample manufactured as described, a reliability test was performed at300° C. under the atmosphere environment. Next, a lifespan where transmittance of the TE light was changed by10% from an initial value and a magnification of extended lifespan with No.1given as a reference were shown in Table2. In the measurement, a spectral photometer U-4100(trade name; manufactured by Hitachi High-Technologies Corporation) was used. TABLE 2Magnification ofSample No.Lifespan (hr)extended lifespan13.21.02110.034.33230.071.74123.338.5 From the results, the lifespan is significantly increased by the formation of the dielectric layer, and No.3(width of the dielectric layer is20nm) shows the highest value in the magnification of the extended lifespan. Here, the formed first dielectric layer13(aluminum oxide) has a lattice constant greater than that of the metal layer12(aluminum) by substantially20%. Therefore, like the case of No.4, it is considered that when the metal layer is converted into the first dielectric layer13by40% or more with respect to the width (60nm) of the metal layer12before the ozone processing, crystal defects occur according to the change in volume, and as a result thereof, oxygen is introduced by using the crystal defects as an introduction path and thereby the oxidation is progressed. From the above description, it could be seen that in the case of the test-produced polarization device, when the width L2of the first dielectric layer13was controlled in a range of25% to40% inclusive with respect to the width of the metal layer12before the ozone processing, it was possible to manufacture the polarization device having the longest product lifespan. From the results, it was confirmed that the reflection type polarization device having the configuration of the invention had superior optical characteristics and the configuration of the invention was effective for solving the problems. Optical Characteristic Evaluation by Simulation Analysis Next, a simulation analysis result of the absorption type polarization device including the second dielectric layer14according to the first embodiment will be described. In the analysis, an evaluation was performed under an assumption that the polarization device according to the invention was applied to a polarization device for a light valve of a liquid crystal projector. The polarization device according to the invention is formed of an inorganic material and the heat resistance is high, such that it is possible to apply the polarization device as a pre-polarization plate of the liquid crystal projector including a high output light source. In the above-described pre-polarization plate, it is important to have high optical transmittance with respect to TM light and to transmit the TM light well. On the other hand, as described above, two sheets of polarization devices absorb the TE light in cooperation with each other, such that the absorption rate of the TE light is not necessary to be so high. Specifically, when the transmittance of the TM light is greater than80%, and the absorption rate of the TE light is greater than40%, there is no problem in use. In regard to the absorption rate of the TE light, it is more preferable to be greater than50% so as to reduce the burden to two sheets of polarization devices. In addition, to prevent the TE light from being reflected from the pre-polarization plate and returning to the light valve, it is preferable that the reflectance of the TE light is small, and more preferably,20% or less. Here, in the analysis described below, the evaluation was performed with a reference that the transmittance of the TM light was greater than80%, the reflectance of the TE light was less than20%, and the absorption rate of the TE light was greater than40%. In the simulation analysis, the shape of the polarization device and a refraction index of a constituent material or the like were set as parameters by using GSolver that is an analysis software manufactured by Grating Solver Development Company. A numerical calculation was performed by using a model where the metal layer12(aluminum), the first dielectric layer13(aluminum oxide), and the second dielectric layer14(germanium) were formed in this order from the substrate. In the first embodiment (FIGS.1A and1B), the entire surface of the metal layer12was covered by the first dielectric layer13, and the top part13c of the first dielectric layer13was covered by the second dielectric layer14. In the calculation, the setting was as follows. The height H1of the aluminum (metal layer12):80nm, the width L1:20nm, the height of H2of the aluminum oxide (first dielectric layer13):20nm, the width L2:20nm, the height of germanium (second dielectric layer14):0to30nm, the width L3:60nm, the width S of the groove portion15in the Y-axis direction:80nm, and the cycle P of the first dielectric layer13(or the metal layer12) was140nm. In addition, as the refraction index and an extinction coefficient of the constituent material of the above-described polarization device, each parameter stored in the GSolver was used. In the above-described model, a change in characteristics in a case of changing the thickness of the germanium was obtained.FIGS.8A to8Cshow a graph illustrating a simulation result in each characteristic of the transmission, the reflection, and the absorption with respect to the TM light and the TE light.FIGS.8A to8Cshow the transmission characteristic, the reflection characteristic, and the absorption characteristic, respectively, in which the thickness of the germanium is shown in a horizontal axis and the value (unit: %) in each optical characteristic at a wavelength of532nm (green color) is shown in a vertical axis. Here, the height of the germanium was changed from0to30nm. From the analysis result, it could be seen that as the height of the germanium increased, the transmittance and reflectance of the TE light decreased and the absorption rate of the TE light increased, and it was obvious that the optical characteristic of the TE light was seriously affected by the height of the germanium. In a case of being used as the above-described absorption type polarization device, it is preferable that a region where the absorption rate of the TE light is40% or more and the reflectance is20% or less is selected, and specifically, the height of the germanium is set to a value between3nm and15nm. In addition, since the absorption rate of the TE light is reduced when the height of the germanium becomes10nm or more, it is preferable that the height of the germanium is set to a value between3nm and8nm. From these results, it was confirmed that the absorption type polarization device having the configuration of the invention had superior optical characteristics and the configuration of the invention was effective for solving the problems. The entire disclosure of Japanese Patent Application No.2010-136851, filed on Jun.16,2010is expressly incorporated by reference herein. | 44,635 |
RE49886 | DESCRIPTION OF THE EMBODIMENTS The present invention will now be described in detail with reference to the drawings showing an embodiment thereof. FIG.1is a diagram schematically showing an overall arrangement of an image processing system according to embodiments of the present invention. This image processing system is comprised of a multifunctional peripheral (hereafter referred to as “the MFP”)101and a file server102, which are connected to each other so that they can communicate with each other. The MFP101is connected to a public telephone line network110. It should be noted that the MFP101is an exemplary image processing apparatus, and the file server102is an exemplary file management apparatus. The LAN100may be either a wired LAN or a wireless LAN. Other apparatuses such as a client computer (hereafter referred to as “the client PC”), not shown, which instructs the MFP101to perform printing or the like are also connected to the LAN100. The MFP101is capable of sending image data (sending image files) to destinations, which are folders in the file server102, using SMB (Server Message Block) or FTP (File Transfer Protocol). It should be noted that folders not only in the file server102but also in the client PC, not shown, mentioned above may be destinations. The MFP101is also capable of sending image data by electronic mail (by mail) via a mail server, not shown. The MFP101is able to carry out communications with (sending and receiving image data to and from) a facsimile, not shown, because it is connected to the public telephone line network110. FIG.2is a block diagram schematically showing a hardware arrangement of the MFP101. The MFP101has a control unit210, an operation unit220, a printer unit221, a scanner unit222, and a modem unit223. The control unit210has a CPU211, a ROM212, a RAM213, an HDD214, an operation unit I/F215, a printer I/F216, a scanner I/F217, a modem I/F218, and a network I/F219. The control unit210controls the overall operation of the MFP101. The CPU211reads control programs stored in the ROM212, expands them in a work area of the RAM213to provide various types of control such as printing control, reading control, and transmission control. The RAM213is used as a temporary storage area such as main memory and a work area for the CPU211. The HDD214stores image data, various programs, and various setting information, history information, and result information on the MFP101. It should be noted that concrete examples of the setting information on the MFP101include information on settings on languages to be displayed on a touch panel (to be described later), which are allowed to be set for each user, and information on languages for use in performing automatic report printing. Also, concrete example of the history information on the MFP101include information on histories of facsimile transmission and reception, and information on results of predetermined jobs such as file transmission. mail transmission. and printing. The operation unit I/F215connects the operation unit220and the CPU211to each other. The operation unit220is comprised of, for example, the touch panel, which is a liquid crystal display having a touch panel function, and a keyboard (hardware buttons). The printer I/F216connects the printer unit221and the CPU211to each other. Image data to be printed by the printer unit221is transferred from the control unit210to the printer unit221via the printer I/F216and printed on a recording medium such as a sheet by the printer unit221. The scanner I/F217connects the scanner unit222and the CPU211to each other. The scanner unit222reads an image off an original to generate image data and inputs it to the control unit210via the scanner I/F217. The MFP101is able to send the image data generated by the scanner unit222. The modem I/F218connects the modem223and the CPU211to each other. The modem223connects the control unit210to the public telephone line network110. The modem223sends and receives image data to and from the facsimile, not shown, on the public telephone line network110. The network I/F219connects the control unit210to the LAN100. The network I/F219sends image data and information to the file server102, the client PC, and so on, which are external apparatuses on the LAN100, and on the other hand, receives various types of information from the external apparatuses on the LAN100. FIG.3is a view showing an exemplary operation screen displayed on the touch panel which the operation unit220has. The operation screen300inFIG.3is displayed on the touch panel by a system administrator of the MFP101logging into the MFP101and operating the operation screen220based on his or her own right when registering a display language which he or she uses (hereafter referred to as “the administrator's display language”). It should be noted that before the administrator's display language is set, the operation screen300inFIG.3is displayed on the touch panel, which the operation unit220has, in a default display language set in advance for the MFP101irrespective of who logs into the MFP101. The default display language is also used in a case where a personalizing function of displaying different languages on the touch panel according to users is off, a case where a user who logs in has registered no display language for him or her, a case where a guest user has logged into the apparatus, and so on as will be described alter. A language information field301in which a plurality of languages is listed is displayed on the operation screen300,10and languages displayed in the language information field301are display languages that can be set. The system administrator is allowed to select a desired language as the administrator's display language (apparatus language) from the languages displayed in the language information field301. The system administrator touches a desired language among languages displayed in the language information field301and depresses an OK button. This completes setting of the administrator's display language, and setting information on the administrator's display language thus set is stored in the HDD214. When the system administrator logs into the MFP101after the administrator's display language is set, various types of information are displayed on the touch panel in the set administrator's display language. FIG.4is a view showing an exemplary display language management table in the MFP101. The display language management table400inFIG.4is comprised of combinations of user names401and display languages402and stored in the HDD214. The user names401are user information managed in the display language management table400, and they are, for example, last names, full names, or nicknames of users or ID numbers of users. The display languages402are display language information associated with users identified by the user names401. For example, when a user A uses the MFP101, Japanese is displayed on the touch panel, and when a user B uses the MFP101, English is displayed on the touch panel. This will be described later in detail with reference to a flowchart ofFIG.9. FIG.5Ais a view showing an exemplary operation screen displayed on the touch panel of the operation unit220when manual report printing is to be performed. In manual report printing, a count obtained by counting the number of sheets printed by the MFP101is printed. The present invention, however, is not limited to this, but other reports (for example, a communication management report and a transmission result report, to be described later) may be manually output. Information501printed on a report to be output and a report print button502for use in instructing execution of report printing are displayed on the touch panel. The information501, here, is comprised of information on processes such as copying (monochrome) and printing (monochrome) and the number of sheets processed in the processes, but the information501is not limited to them but may include other information. By seeing the information501and depressing (touching) the report print button502, a user issues an instruction to perform manual report printing.FIG.5Bshows an exemplary count report which is an output matter obtained by the user depressing the report print button502. FIG.6Ais a view showing an exemplary operation screen displayed on the touch panel of the operation unit220when settings on automatic printing of a communication management report, which is automatic report printing, are to be configured. The control unit210of the MFP101manages communication histories with external apparatuses (the file server102, the client PC, the facsimile, and so on), and the communication histories are stored in the HDD214. The CPU211increments the total number of communication histories whenever communication histories are updated, and when the count reaches 100, the CPU211performs automatic report printing and resets the count to zero. “Automatic printing after 100 communications” displayed inFIG.6Aindicates a condition as to the timing with which a communication management report for use in managing communication histories is to automatically output. When the total number of communication histories satisfies this condition (100 communications), automatic report printing is performed. A switch601for selectively executing (turning on and off) automatic report printing is displayed on the touch panel. When the switch601is ON, a communication management report on which communication histories managed by the MFP101are printed is automatically output when the number of communication histories reaches 100.FIG.6Bshows an exemplary communication management report. FIG.7Ais a view showing an exemplary operation screen displayed on the touch panel of the operation unit220when settings on printing of a transmission result report, which is automatic report printing, are to be configured. An only-error-time button701is a switch for making a setting that performs automatic report printing when a transmission error occurs. Thus, when the only-error-time button701is selected, a transmission result report showing a result of transmission of image data to an external apparatus is automatically printed (the file server102, the client PC, the facsimile, or the like) only when the transmission ends in failure.FIG.7Bshows an exemplary transmission result report in a case where an error occurs. An ON button702is a switch for making a setting that performs automatic report printing without exception irrespective of transmission results. When the ON button702is selected, a transmission result report showing a result of transmission of image data to an external apparatus is automatically printed without exception irrespective of whether or not the transmission is successful.FIG.7Cshows an exemplary transmission result report output in a case where transmission is successfully completed. An OFF button703is a switch for making a setting that does not perform autonomic printing of a transmission result report. FIG.8is a view showing a report management table800for the MFP101. The report management table800is comprised of a report name field801, an autonomic report field802, and a result report field803, and is stored in the HDD214. In the report name field801, names of various reports such as a count report, a communication management report, and a transmission result report described above with reference toFIGS.5A to7Care stored. In the autonomic report field802, settings as to whether the automatic report printing function is on or off are stored. In the result report field803, settings as to whether or not a report with a corresponding report name is a result report, that is, whether or not, in a case where an image data transmission job or the like has been executed, a report showing a result thereof is to be output (ON or OFF) are stored. For a transmission result report, in the result report field803, a selection result “only error time”, “ON”, or “OFF” shown inFIG.7Ais stored, and “ON” on the right hand of “ON-ON” inFIG.8indicates this setting. Upon receiving a manual or automatic report printing instruction, the CPU211of the MFP101refers to information in the report management table800and determines whether or not the received report printing instruction is an instruction to perform automatic report printing and whether or not the received report printing instruction is an instruction to perform result report printing. FIG.9is a flowchart of a process in which a language to be displayed on the touch panel of the operation unit220is determined with respect to each user. Processes in the flowchart inFIG.9are implemented by the CPU211expanding a control program, which is stored in the HDD214, in a work area of the RAM213. In step S901, the CPU211receives authentication information input by a user. Next, in step S902, the CPU211authenticates and identifies the user who uses the MFP101based on the authentication information input in the step S901. For example, when using the MFP101, each user lets an ID card reader (not shown inFIG.1or2), which is provided in the MFP101, read his/her own ID card. The CPU211of the MFP101identifies a user by collating information on an ID card read by the ID card reader with the display language management table400. The user authentication method, however, is not limited to this, but any method may be used as long as users can be identified. Then, in step S903, the CPU211obtains a language (display language) set for the user authenticated in the step S902from the display language management table400(seeFIG.4). For example, when the authenticated user is identified as a user A, Japanese is obtained, and when the authenticated user is identified as a user B, English is obtained. It should be noted that when the system administrator logs in, the administrator's display language set on the operation screen300described earlier with reference toFIG.3is obtained. Then, in step S904, the CPU211sets the language obtained in the step S903as a display language for information to be displayed on the touch panel of the operation unit220. This setting is stored in the HDD214. After that, in step S905, the CPU211displays a main screen (main menu) in the language set in the step S904on the touch panel of the operation unit220, followed by termination of the process. FIG.10is a flowchart of a report printing process carried out by the MFP101according to a first embodiment. Processes in the flowchart inFIG.10are implemented by the CPU211of the control unit201expanding a control program, which is stored in the HDD214, in a work area of the RAM213. The process inFIG.10is started in response to the MFP101receiving an instruction to perform report printing. In step S1001, the CPU211determines whether or not the instruction is an instruction to perform automatic report printing based on the report management table800(seeFIG.8). When the instruction is an instruction to perform automatic report printing (YES in the step S1001), that is, when the autonomic report field802corresponding to a report name for which the printing instruction has been issued is ON, the process proceeds to step S1002. On the other hand, when the instruction is not an instruction to perform automatic report printing (NO in the step S1001), that is, when the autonomic report field802corresponding to a report name for which the printing instruction has been issued is OFF, the process proceeds to step S1005. In the step S1002, the CPU211determines whether or not the instruction is an instruction to perform result report printing based on the report management table800. When the instruction is an instruction to perform result report printing (YES in the step S1002), that is, when the result report field803corresponding to a report name for which the printing instruction has been issued is ON, the process proceeds to step S1003. On the other hand, when the instruction is not an instruction to perform result report printing (NO in the step S1002), that is, when the result report field803corresponding to a report name for which the printing instruction has been issued is OFF, the process proceeds to step S1006. In the step S1003, the CPU211refers to the report management table800inFIG.8and causes the process to branch according to print settings in the transmission result report shown inFIG.7A. When the setting on transmission result report printing is “ON”, the process proceeds to the step S1005. When the setting on transmission result report printing is “only-error-time”, the process proceeds to step S1004. When the setting on transmission result report printing is “OFF”, the CPU211terminates the process without printing the transmission result report. In the step S1004, the CPU211determines whether or not a transmission error has occurred. When the CPU211determines that a transmission error has actually occurred (YES in the step S1004), the process proceeds to the step S1005, and when no transmission error has occurred (NO in the step S1004), the CPU211terminates the process without printing the transmission result report. In the step S1005, the CPU211obtains a report print language from the display languages for the operation unit220, which were stored in the HDD214in the step S904inFIG.9. For example, as the report print language, Japanese is obtained for the user A, and English is obtained for the user B. In the step S1006, the CPU211obtains the administrator's display language set on the operation screen300inFIG.3as the report print language from the HDD214. After the steps S1005and S1006are completed. the process proceeds to step S1007, in which the CPU211in turn creates details of a report. for which the printing instruction has been issued, in the languages obtained in the steps S1005and S1006. Then, in step S1008, the CPU211causes the printer unit211to print and output the report created in the step S1007, followed by termination of the process. It should be noted in the report management table800inFIG.8, the automatic report filed802is ON and the result report field803is ON for the transmission result report, and the setting on printing of the transmission result report print setting inFIG.7Ais ON. In this case, according to the flowchart ofFIG.10, a transmission result report is printed in the display language for the operation unit220. This takes into consideration the fact that a transmission result report is used in many cases by a user who has executed the transmission job. The present invention, however, is not limited to this arrangement, but a transmission result report may be output in the administrator's display language set on the operation screen300inFIG.3. In this case, when it is determined in the step S1003that the transmission result report print setting inFIG.7Ais ON, the process should proceed to the step S1006, not to the step S1003. As described above, according to the present embodiment, in either manual report printing or automatic report printing, the user of the MFP101performs desired report printing in languages desired by the user and the system administrator. Next, a description will be given of a second embodiment of the present invention. In the following description of the second embodiment, detailed description of the same features as those in the first embodiment, such as the hardware arrangement of the image processing system, is omitted. In the second embodiment, even in a case where OFF (the OFF button703) or only-error-time (the only-error-time button701) is selected inFIG.7A, a transmission result report is printed and output in the display language for the operation unit220when the user explicitly selects to print the transmission result report before executing a transmission job. Also, in a case where ON (the ON button702) is selected inFIG.7A, a transmission result report is printed and output in the display language for the operation unit220and the administrator's display language when the user explicitly selects to print the transmission result report before executing a transmission job. FIG.11is a view showing an exemplary operation screen displayed on the touch panel of the operation screen220when the user explicitly makes a setting that prints a transmission result report. The operation screen inFIG.11is displayed on the touch panel by the user depressing, for example, an option button, not shown, displayed on a menu screen, not shown, of the touch panel of the operation unit220when he or she explicitly issues an instruction to print a result report. A transmission result report button1101is a button for the user to explicitly designates printing of a transmission result report when executing a transmission job (file transmission or mail transmission). When the transmission result report button1101is depressed (selected), a transmission result report is printed in a display language for the operation unit220even in a case where OFF or only-error-time is selected in the print setting inFIG.7A. Also, when ON is selected inFIG.7A, a transmission result report is printed in a display language for the operation unit220as usual (when the determination result is ON in the step S1003inFIG.10), and the transmission result report is also printed in an administration's display language. FIGS.12A and12Bare flowcharts of a report printing process carried out by the MFP101according to a second embodiment. Processes in the flowchart inFIGS.12A and12Bare implemented by the CPU211expanding a control program, which is stored in the HDD214, in a work area of the RAM213. The process inFIGS.12A and12Bis started in response to the MFP101receiving an instruction to perform report printing. First, in step S1201, the CPU211determines whether or not the instruction is an instruction to perform automatic report printing based on the report management table800(seeFIG.8). When the instruction is an instruction to perform automatic report printing (YES in the step S1201), that is, when the autonomic report field802corresponding to a report name for which the printing instruction has been issued is ON, the process proceeds to step S1202. On the other hand, when the instruction is not an instruction to perform automatic report printing (NO in the step S1201), that is, when the autonomic report field802corresponding to a report name for which the printing instruction has been issued is OFF, the process proceeds to step S1208. In the step S1202, the CPU211determines whether or not the instruction is an instruction to perform result report printing based on the report management table800. When the instruction is an instruction to perform result report printing (YES in the step S1202), that is, when the result report field803corresponding to a report name for which the printing instruction has been issued is ON, the process proceeds to step S1203. On the other hand, when the instruction is not an instruction to perform result report printing (NO in the step S1202), that is, when the result report field803corresponding to a report name for which the printing instruction has been issued is OFF, the process proceeds to step S1210. In the step S1203, the CPU211determines whether or not the transmission result report button1101inFIG.11is selected, that is, whether or not an optional transmission result report is enabled. When the transmission result report button1101is selected (YES in the step S1203), the process proceeds to step S1204. When the transmission result report button1101is not selected (NO in the step S1203), the process proceeds to step S1205. In the step S1204, the CPU211obtains a setting on transmission result report printing inFIG.7Afrom the report management table800inFIG.8and causes the process to branch according to the obtained information. When the setting inFIG.7Ais “only-error-time” or “OFF”, the process proceeds to the step S1208, and when the setting inFIG.7Ais “ON”, the process proceeds to step S1209. In the step S1205, the CPU211determines whether or not the setting inFIG.7Ais “ON”. When the setting inFIG.7Ais “ON” (YES in the step S1205), the process proceeds to the step S1208, and when the setting inFIG.7Ais not “ON” (NO in the step S1205), the process proceeds to the step S1206. In the step S1206, the CPU211determines whether or not the setting inFIG.7Ais “OFF”. When the setting inFIG.7Ais “OFF” (YES in the step S1206), the CPU211terminates the process, and when the setting inFIG.7Ais not “OFF”, that is, when the setting inFIG.7Ais configured at “only-error-time” (NO in the step S1206), the process proceeds to step S1207. In the step S1207, the CPU211determines whether or not a transmission error has occurred. When a transmission error has actually occurred (YES in the step S1207), the process proceeds to the step S1208, and when no transmission error has occurred (NO in the step S1207), the CPU211terminates the process. In the step S1208, the CPU211obtains a report print language from display languages for the operation unit220, which were stored in the HDD214in the step S904inFIG.9. For example, as the report print language, Japanese is obtained for a user A, and English is obtained for a user B. In the step S1209, as the report print language, the CPU211obtains a display language for the operation unit220, which was stored in the HDD214in the step S904inFIG.9, and obtains the administrator's display language set on the operation screen300inFIG.3from the HDD214. In the step S1210, the CPU211obtains the administrator's display language set on the operation screen300inFIG.3from the HDD214as the report print language. After the steps S1208, S1209, and S1210are completed, the process proceeds to step S1211, in which the CPU211in turn creates details of a report for which the printing instruction has been issued in the languages obtained in the respective steps S1208, S1209, and S1210. Then, in step S1212, the CPU211causes the printer unit211to print and output the report created in the step S1211, followed by termination of the process. It should be noted when the display language for the operation unit220and the administrator's display language are obtained in the step S1209, a transmission result report written in the display language for the operation unit220and a transmission result report written in the administrator's display language are output. At this time, the transmission result reports written in the respective languages may be printed on different sheets, resulting in two sheets being output, or the transmission result reports written in the respective languages may be printed collectively on one sheet, resulting in one sheet being output. As described above, according to the present embodiment, by explicitly selecting printing of a transmission result report before executing a transmission job, the user prints the transmission result report in the display language for the operation unit220. This enhances the convenience for the user who issues an instruction to execute a transmission job. Moreover, a transmission result report written in both the display language for the operation unit220and the administrator's display language is printed, and this enhances the convenience for both the user who issues an instruction to execute a transmission job and the system administrator. It should be noted in the embodiments described above, the MFP101carries out the processes in the flowcharts ofFIGS.9and10using one memory (the RAM213or the HDD214). The present invention, however, is not limited to this, but for example, a plurality of CPUs may work in collaboration with each other using one or a plurality of memories to carry out the processes in the flowcharts ofFIGS.9and10. Other Embodiments Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. This application claims the benefit of Japanese Patent Application No. 2013-228222, filed Nov. 1, 2013, which is hereby incorporated by reference wherein in its entirety. | 29,977 |
RE49887 | DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS The following describes in further detail suitable apparatus and possible mechanisms for encoding an enhancement layer sub-picture without significantly sacrificing the coding efficiency. In this regard reference is first made toFIGS.1and2, whereFIG.1shows a block diagram of a video coding system according to an example embodiment as a schematic block diagram of an exemplary apparatus or electronic device50, which may incorporate a codec according to an embodiment of the invention.FIG.2shows a layout of an apparatus according to an example embodiment. The elements ofFIGS.1and2will be explained next. The electronic device50may for example be a mobile terminal or user equipment of a wireless communication system. However, it would be appreciated that embodiments of the invention may be implemented within any electronic device or apparatus which may require encoding and decoding or encoding or decoding video images. The apparatus50may comprise a housing30for incorporating and protecting the device. The apparatus50further may comprise a display32in the form of a liquid crystal display. In other embodiments of the invention the display may be any suitable display technology suitable to display an image or video. The apparatus50may further comprise a keypad34. In other embodiments of the invention any suitable data or user interface mechanism may be employed. For example the user interface may be implemented as a virtual keyboard or data entry system as part of a touch-sensitive display. The apparatus may comprise a microphone36or any suitable audio input which may be a digital or analogue signal input. The apparatus50may further comprise an audio output device which in embodiments of the invention may be any one of: an earpiece38, speaker, or an analogue audio or digital audio output connection. The apparatus50may also comprise a battery40(or in other embodiments of the invention the device may be powered by any suitable mobile energy device such as solar cell, fuel cell or clockwork generator). The apparatus may further comprise a camera42capable of recording or capturing images and/or video. The apparatus50may further comprise an infrared port for short range line of sight communication to other devices. In other embodiments the apparatus50may further comprise any suitable short range communication solution such as for example a Bluetooth wireless connection or a USB/firewire wired connection. The apparatus50may comprise a controller56or processor for controlling the apparatus50. The controller56may be connected to memory58which in embodiments of the invention may store both data in the form of image and audio data and/or may also store instructions for implementation on the controller56. The controller56may further be connected to codec circuitry54suitable for carrying out coding and decoding of audio and/or video data or assisting in coding and decoding carried out by the controller. The apparatus50may further comprise a card reader48and a smart card46, for example a UICC and UICC reader for providing user information and being suitable for providing authentication information for authentication and authorization of the user at a network. The apparatus50may comprise radio interface circuitry52connected to the controller and suitable for generating wireless communication signals for example for communication with a cellular communications network, a wireless communications system or a wireless local area network. The apparatus50may further comprise an antenna44connected to the radio interface circuitry52for transmitting radio frequency signals generated at the radio interface circuitry52to other apparatus(es) and for receiving radio frequency signals from other apparatus(es). The apparatus50may comprise a camera capable of recording or detecting individual frames which are then passed to the codec54or the controller for processing. The apparatus may receive the video image data for processing from another device prior to transmission and/or storage. The apparatus50may also receive either wirelessly or by a wired connection the image for coding/decoding. With respect toFIG.3, an example of a system within which embodiments of the present invention can be utilized is shown. The system10comprises multiple communication devices which can communicate through one or more networks. The system10may comprise any combination of wired or wireless networks including, but not limited to a wireless cellular telephone network (such as a GSM, UMTS, CDMA network etc), a wireless local area network (WLAN) such as defined by any of the IEEE 802.x standards, a Bluetooth personal area network, an Ethernet local area network, a token ring local area network, a wide area network, and the Internet. The system10may include both wired arid wireless communication devices and/or apparatus50suitable for implementing embodiments of the invention. For example, the system shown inFIG.3shows a mobile telephone network11and a representation of the internet28. Connectivity to the internet28may include, but is not limited to, long range wireless connections, short range wireless connections, and various wired connections including, but not limited to, telephone lines, cable lines, power lines, and similar communication pathways. The example communication devices shown in the system10may include, but are not limited to, an electronic device or apparatus50, a combination of a personal digital assistant (PDA) and a mobile telephone14, a PDA16, an integrated messaging device (IMD)18, a desktop computer20, a notebook computer22. The apparatus50may be stationary or mobile when carried by an individual who is moving. The apparatus50may also be located in a mode of transport including, but not limited to, a car, a truck, a taxi, a bus, a train, a boat, an airplane, a bicycle, a motorcycle or any similar suitable mode of transport. The embodiments may also be implemented in a set-top box; i.e. a digital TV receiver, which may/may not have a display or wireless capabilities, in tablets or (laptop) personal computers (PC), which have hardware or software or combination of the encoder/decoder implementations, in various operating systems, and in chipsets, processors, DSPs and/or embedded systems offering hardware/software based coding. Some or further apparatus may send and receive calls and messages and communicate with service providers through a wireless connection25to a base station24. The base station24may be connected to a network server26that allows communication between the mobile telephone network11and the internet28. The system may include additional communication devices and communication devices of various types. The communication devices may communicate using various transmission technologies including, but not limited to, code division multiple access (CDMA), global systems for mobile communications (GSM), universal mobile telecommunications system (UMTS), time divisional multiple access (TDMA), frequency division multiple access (FDMA), transmission control protocol-internet protocol (TCP-IP), short messaging service (SMS), multimedia messaging service (MMS), email, instant messaging service (IMS), Bluetooth, IEEE 802.11 and any similar wireless communication technology. A communications device involved in implementing various embodiments of the present invention may communicate using various media including, but not limited to, radio, infrared, laser, cable connections, and any suitable connection. Video codec consists of an encoder that transforms the input video into a compressed representation suited for storage/transmission and a decoder that can uncompress the compressed video representation back into a viewable form. Typically encoder discards some information in the original video sequence in order to represent the video in a more compact form (that is, at lower bitrate). Typical hybrid video codecs, for example many encoder implementations of ITU-T H.263 and H.264, encode the video information in two phases. Firstly pixel values in a certain picture area (or “block”) are predicted for example by motion compensation means (finding and indicating an area in one of the previously coded video frames that corresponds closely to the block being coded) or by spatial means (using the pixel values around the block to be coded in a specified manner). Secondly the prediction error, i.e. the difference between the predicted block of pixels and the original block of pixels, is coded. This is typically done by transforming the difference in pixel values using a specified transform (e.g. Discrete Cosine Transform (DCT) or a variant of it), quantizing the coefficients and entropy coding the quantized coefficients. By varying the fidelity of the quantization process, encoder can control the balance between the accuracy of the pixel representation (picture quality) and size of the resulting coded video representation (file size or transmission bitrate). Inter prediction, which may also be referred to as temporal prediction, motion compensation, or motion-compensated prediction, reduces temporal redundancy. In inter prediction the sources of prediction are previously decoded pictures. Intra prediction utilizes the fact that adjacent pixels within the same picture are likely to be correlated. Intra prediction can be performed in spatial or transform domain, i.e., either sample values or transform coefficients can be predicted. Intra prediction is typically exploited in intra coding, where no inter prediction is applied. One outcome of the coding procedure is a set of coding parameters, such as motion vectors and quantized transform coefficients. Many parameters can be entropy-coded more efficiently if they are predicted first from spatially or temporally neighboring parameters. For example, a motion vector may be predicted from spatially adjacent motion vectors and only the difference relative to the motion vector predictor may be coded. Prediction of coding parameters and intra prediction may be collectively referred to as in-picture prediction. FIG.4shows a block diagram of a video encoder suitable for employing embodiments of the invention.FIG.4presents an encoder for two layers, but it would be appreciated that presented encoder could be similarly extended to encode more than two layers.FIG.4illustrates an embodiment of a video encoder comprising a first encoder section500for a base layer and a second encoder section502for an enhancement layer. Each of the first encoder section500and the second encoder section502may comprise similar elements for encoding incoming pictures. The encoder sections500,502may comprise a pixel predictor302,402, prediction error encoder303,403and prediction error decoder304,404.FIG.4also shows an embodiment of the pixel predictor302,402as comprising an inter-predictor306,406, an intra-predictor308,408, a mode selector310,410, a filter316,416, and a reference frame memory318,418. The pixel predictor302of the first encoder section500receives300base layer images of a video stream to be encoded at both the inter-predictor306(which determines the difference between the image and a motion compensated reference frame318) and the intra-predictor308(which determines a prediction for an image block based only on the already processed parts of current frame or picture). The output of both the inter-predictor and the intra-predictor are passed to the mode selector310. The intra-predictor308may have more than one intra-prediction modes. Hence, each mode may perform the intra-prediction and provide the predicted signal to the mode selector310. The mode selector310also receives a copy of the base layer picture300. Correspondingly, the pixel predictor402of the second encoder section502receives400enhancement layer images of a video stream to be encoded at both the inter-predictor406(which determines the difference between the image and a motion compensated reference frame418) and the intra-predictor408(which determines a prediction for an image block based only on the already processed parts of current frame or picture). The output of both the inter-predictor and the intra-predictor are passed to the mode selector410. The intra-predictor408may have more than one intra-prediction modes. Hence, each mode may perform the intra-prediction and provide the predicted signal to the mode selector410. The mode selector410also receives a copy of the enhancement layer picture400. Depending on which encoding mode is selected to encode the current block, the output of the inter-predictor306,406or the output of one of the optional intra-predictor modes or the output of a surface encoder within the mode selector is passed to the output of the mode selector310,410. The output of the mode selector is passed to a first summing device321,421. The first summing device may subtract the output of the pixel predictor302,402from the base layer picture300/enhancement layer picture400to produce a first prediction error signal320,420which is input to the prediction error encoder303,403. The pixel predictor302,402further receives from a preliminary reconstructor339,439the combination of the prediction representation of the image block312,412and the output338,438of the prediction error decoder304,404. The preliminary reconstructed image314,414may be passed to the intra-predictor308,408and to a filter316,416. The filter316,416receiving the preliminary representation may filter the preliminary representation and output a final reconstructed image340,440which may be saved in a reference frame memory318,418. The reference frame memory318may be connected to the inter-predictor306to be used as the reference image against which a future base layer picture300is compared in inter-prediction operations. Subject to the base layer being selected and indicated to be source for inter-layer sample prediction and/or inter-layer motion information prediction of the enhancement layer according to some embodiments. the reference frame memory318may also be connected to the inter-predictor406to be used as the reference image against which a future enhancement layer pictures400is compared in inter-prediction operations. Moreover, the reference frame memory418may be connected to the inter-predictor406to be used as the reference image against which a future enhancement layer picture400is compared in inter-prediction operations. Filtering parameters from the filter316of the first encoder section500may be provided to the second encoder section502subject to the base layer being selected and indicated to be source for predicting the filtering parameters of the enhancement layer according to some embodiments. The prediction error encoder303,403comprises a transform unit342,442and a quantizer344,444. The transform unit342,442transforms the first prediction error signal320,420to a transform domain. The transform is, for example, the DCT transform. The quantizer344,444quantizes the transform domain signal, e.g. the DCT coefficients, to form quantized coefficients. The prediction error decoder304,404receives the output from the prediction error encoder303,403and performs the opposite processes of the prediction error encoder303,403to produce a decoded prediction error signal338,438which, when combined with the prediction representation of the image block312,412at the second summing device339,439, produces the preliminary reconstructed image314,414. The prediction error decoder may be considered to comprise a dequantizer361,461, which dequantizes the quantized coefficient values, e.g. DCT coefficients. to reconstruct the transform signal and an inverse transformation unit363,463, which performs the inverse transformation to the reconstructed transform signal wherein the output of the inverse transformation unit363,463contains reconstructed block(s). The prediction error decoder may also comprise a block filter which may filter the reconstructed block(s) according to further decoded information and filter parameters. The entropy encoder330,430receives the output of the prediction error encoder303,403and may perform a suitable entropy encoding/variable length encoding on the signal to provide error detection and correction capability. The outputs of the entropy encoders330,430may be inserted into a bitstream e.g. by a multiplexer508. The H.264/AVC standard was developed by the Joint Video Team (JVT) of the Video Coding Experts Group (VCEG) of the Telecommunications Standardization Sector of International Telecommunication Union (ITU-T) and the Moving Picture Experts Group (MPEG) of International Organisation for Standardization (ISO)/International Electrotechnical Commission (IEC). The H.264/AVC standard is published by both parent standardization organizations, and it is referred to as ITU-T Recommendation H.264 and ISO/IEC International Standard 14496-10, also known as MPEG-4 Part 10 Advanced Video Coding (AVC). There have been multiple versions of the H.264/AVC standard, integrating new extensions or features to the specification. These extensions include Scalable Video Coding (SVC) and Multiview Video Coding (MVC). The High Efficiency Video Coding (H.265/HEVC) standard was developed by the Joint Collaborative Team-Video Coding (JCT-VC) of VCEG and MPEG. The standard is or will be published by both parent standardization organizations, and it is referred to as ITU-T Recommendation H.265 and ISO/IEC International Standard 23008-2, also known as MPEG-H Part 2 High Efficiency Video Coding (HEVC). There are currently ongoing standardization projects to develop extensions to H.265/HEVC, including scalable, multiview, three-dimensional, and fidelity range extensions, which may be abbreviated SHVC, MV-HEVC, 3D-HEVC, and REXT, respectively. Some key definitions, bitstream and coding structures, and concepts of H.264/AVC and HEVC are described in this section as an example of a video encoder, decoder, encoding method, decoding method, and a bitstream structure, wherein the embodiments may be implemented. Some of the key definitions, bitstream and coding structures, and concepts of H.264/AVC are the same as in HEVC—hence, they are described below jointly. The aspects of the invention are not limited to H.264/AVC or HEVC. but rather the description is given for one possible basis on top of which the invention may be partly or fully realized. Similarly to many earlier video coding standards, the bitstream syntax and semantics as well as the decoding process for error-free bitstreams are specified in H.264/AVC and HEVC. The encoding process is not specified, but encoders must generate conforming bitstreams. Bitstream and decoder conformance can be verified with the Hypothetical Reference Decoder (HRD). The standards contain coding tools that help in coping with transmission errors and losses, but the use of the tools in encoding is optional and no decoding process has been specified for erroneous bitstreams. In the description of existing standards as well as in the description of example embodiments, a syntax element may be defined as an element of data represented in the bitstream. A syntax structure may be defined as zero or more syntax elements present together in the bitstream in a specified order. In the description of existing standards as well as in the description of example embodiments, a phrase “by external means” or “through external means” may be used. For example. an entity, such as a syntax structure or a value of a variable used in the decoding process, may be provided “by external means” to the decoding process. The phrase “by external means” may indicate that the entity is not included in the bitstream created by the encoder, but rather conveyed externally from the bitstream for example using a control protocol. It may alternatively or additionally mean that the entity is not created by the encoder, but may be created for example in the player or decoding control logic or alike that is using the decoder. The decoder may have an interface for inputting the external means, such as variable values. A profile may be defined as a subset of the entire bitstream syntax that is specified by a decoding/coding standard or specification. Within the bounds imposed by the syntax of a given profile it is still possible to require a very large variation in the performance of encoders and decoders depending upon the values taken by syntax elements in the bitstream such as the specified size of the decoded pictures. In many applications, it might be neither practical nor economic to implement a decoder capable of dealing with all hypothetical uses of the syntax within a particular profile. In order to deal with this issue, levels may be used. A level may be defined as a specified set of constraints imposed on values of the syntax elements in the bitstream and variables specified in a decoding/coding standard or specification. These constraints may be simple limits on values. Alternatively or in addition, they may take the form of constraints on arithmetic combinations of values (e.g., picture width multiplied by picture height multiplied by number of pictures decoded per second). Other means for specifying constraints for levels may also be used. Some of the constraints specified in a level may for example relate to the maximum picture size, maximum bitrate and maximum data rate in terms of coding units, such as macroblocks, per a time period, such as a second. The same set of levels may be defined for all profiles. It may be preferable for example to increase interoperability of terminals implementing different profiles that most or all aspects of the definition of each level may be common across different profiles. The elementary unit for the input to an H.264/AVC or HEVC encoder and the output of an H.264/AVC or HEVC decoder, respectively, is a picture. A picture given as an input to an encoder may also referred to as a source picture, and a picture decoded by a decoded may be referred to as a decoded picture. The source and decoded pictures are each comprised of one or more sample arrays, such as one of the following sets of sample arrays:Luma (Y) only (monochrome).Luma and two chroma (YCbCr or YCgCo).Green, Blue and Red (GBR, also known as RGB).Arrays representing other unspecified monochrome or tri-stimulus color samplings (for example, YZX, also known as XYZ). In the following, these arrays may be referred to as luma (or L or Y) and chroma, where the two chroma arrays may be referred to as Cb and Cr; regardless of the actual color representation method in use. The actual color representation method in use can be indicated e.g. in a coded bitstream e.g. using the Video Usability Information (VUI) syntax of H.264/AVC and/or HEVC. A component may be defined as an array or single sample from one of the three sample arrays arrays (luma and two chroma) or the array or a single sample of the array that compose a picture in monochrome format. In H.264/AVC and HEVC, a picture may either be a frame or a field. A frame comprises a matrix of luma samples and possibly the corresponding chroma samples. A field is a set of alternate sample rows of a frame and may be used as encoder input, when the source signal is interlaced. Chroma sample arrays may be absent (and hence monochrome sampling may be in use) or chroma sample arrays may be subsampled when compared to luma sample arrays. Chroma formats may be summarized as follows:In monochrome sampling there is only one sample array, which may be nominally considered the luma array.In 4:2:0 sampling, each of the two chroma arrays has half the height and half the width of the luma array.In 4:2:2 sampling, each of the two chroma arrays has the same height and half the width of the luma array.In 4:4:4 sampling when no separate color planes are in use, each of the two chroma arrays has the same height and width as the luma array. In H.264/AVC and HEVC, it is possible to code sample arrays as separate color planes into the bitstream and respectively decode separately coded color planes from the bitstream. When separate color planes are in use, each one of them is separately processed (by the encoder and/or the decoder) as a picture with monochrome sampling. When chroma subsampling is in use (e.g. 4:2:0 or 4:2:2 chroma sampling), the location of chroma samples with respect to luma samples may be determined in the encoder side (e.g. as pre-processing step or as part of encoding). The chroma sample positions with respect to luma sample positions may be pre-defined for example in a coding standard, such as H.264/AVC or HEVC, or may be indicated in the bitstream for example as part of VUI of H.264/AVC or HEVC. A partitioning may be defined as a division of a set into subsets such that each element of the set is in exactly one of the subsets. In H.264/AVC, a macroblock is a 16×16 block of luma samples and the corresponding blocks of chroma samples. For example, in the 4:2:0 sampling pattern, a macroblock contains one 8×8 block of chroma samples per each chroma component. In H.264/AVC, a picture is partitioned to one or more slice groups, and a slice group contains one or more slices. In H.264/AVC, a slice consists of an integer number of macroblocks ordered consecutively in the raster scan within a particular slice group. When describing the operation of HEVC encoding and/or decoding, the following terms may be used. A coding block may be defined as an N×N block of samples for some value of N such that the division of a coding tree block into coding blocks is a partitioning. A coding tree block (CTB) may be defined as an N×N block of samples for some value of N such that the division of a component into coding tree blocks is a partitioning. A coding tree unit (CTU) may be defined as a coding tree block of luma samples, two corresponding coding tree blocks of chroma samples of a picture that has three sample arrays, or a coding tree block of samples of a monochrome picture or a picture that is coded using three separate color planes and syntax structures used to code the samples. A coding unit (CU) may be defined as a coding block of luma samples, two corresponding coding blocks of chroma samples of a picture that has three sample arrays, or a coding block of samples of a monochrome picture or a picture that is coded using three separate color planes and syntax structures used to code the samples. In some video codecs, such as High Efficiency Video Coding (HEVC) codec, video pictures are divided into coding units (CU) covering the area of the picture. A CU consists of one or more prediction units (PU) defining the prediction process for the samples within the CU and one or more transform units (TU) defining the prediction error coding process for the samples in the said CU. Typically, a CU consists of a square block of samples with a size selectable from a predefined set of possible CU sizes. A CU with the maximum allowed size may be named as LCU (largest coding unit) or coding tree unit (CTU) and the video picture is divided into non-overlapping LCUs. An LCU can be further split into a combination of smaller CUs, e.g. by recursively splitting the LCU and resultant CUs. Each resulting CU typically has at least one PU and at least one TU associated with it. Each PU and TU can be further split into smaller PUs and TUs in order to increase granularity of the prediction and prediction error coding processes, respectively. Each PU has prediction information associated with it defining what kind of a prediction is to be applied for the pixels within that PU (e.g. motion vector information for inter predicted PUs and intra prediction directionality information for intra predicted PUs). The directionality of a prediction mode for ultra prediction, i.e. the prediction direction to be applied in a particular prediction mode, may be vertical, horizontal, diagonal. For example, in HEVC, intra prediction provides up to 33 directional prediction modes, depending on the size of PUs, and each of the intra prediction modes has a prediction direction assigned to it. Similarly each TU is associated with information describing the prediction error decoding process for the samples within the said TU (including e.g. DCT coefficient information). It is typically signalled at CU level whether prediction error coding is applied or not for each CU. In the case there is no prediction error residual associated with the CU, it can be considered there are no TUs for the said CU. The division of the image into CUs. and division of CUs into PUs and TUs is typically signalled in the bitstream allowing the decoder to reproduce the intended structure of these units. In HEVC, a picture can be partitioned in tiles, which are rectangular and contain an integer number of LCUs. In HEVC, the partitioning to tiles forms a regular grid, where heights and widths of tiles differ from each other by one LCU at the maximum. In a draft HEVC, a slice is defined to be an integer number of coding tree units contained in one independent slice segment and all subsequent dependent slice segments (if any) that precede the next independent slice segment (if any) within the same access unit. In HEVC, a slice segment is defined to be an integer number of coding tree units ordered consecutively in the tile scan and contained in a single NAL unit. The division of each picture into slice segments is a partitioning. In HEVC, an independent slice segment is defined to be a slice segment for which the values of the syntax elements of the slice segment header are not inferred from the values for a preceding slice segment, and a dependent slice segment is defined to be a slice segment for which the values of some syntax elements of the slice segment header are inferred from the values for the preceding independent slice segment in decoding order. In HEVC, a slice header is defined to be the slice segment header of the independent slice segment that is a current slice segment or is the independent slice segment that precedes a current dependent slice segment, and a slice segment header is defined to be a part of a coded slice segment containing the data elements pertaining to the first or all coding tree units represented in the slice segment. The CUs are scanned in the raster scan order of LCUs within tiles or within a picture, if tiles are not in use. Within an LCU, the CUs have a specific scan order.FIG.5shows an example of a picture consisting of two tiles partitioned into square coding units (solid lines) which have been further partitioned into rectangular prediction units (dashed lines). The decoder reconstructs the output video by applying prediction means similar to the encoder to form a predicted representation of the pixel blocks (using the motion or spatial information created by the encoder and stored in the compressed representation) and prediction error decoding (inverse operation of the prediction error coding recovering the quantized prediction error signal in spatial pixel domain). After applying prediction and prediction error decoding means the decoder sums up the prediction and prediction error signals (pixel values) to form the output video frame. The decoder (and encoder) can also apply additional filtering means to improve the quality of the output video before passing it for display and/or storing it as prediction reference for the forthcoming frames in the video sequence. The filtering may for example include one more of the following: deblocking, sample adaptive offset (SAO), and/or adaptive loop filtering (ALF). In SAO, a picture is divided into regions where a separate SAO decision is made for each region. The SAO information in a region is encapsulated in a SAO parameters adaptation unit (SAO unit) and in HEVC, the basic unit for adapting SAO parameters is CTU (therefore an SAO region is the block covered by the corresponding CTU). In the SAO algorithm, samples in a CTU are classified according to a set of rules and each classified set of samples are enhanced by adding offset values. The offset values are signalled in the bitstream. There are two types of offsets: 1) Band offset 2) Edge offset. For a CTU, either no SAO or band offset or edge offset is employed. Choice of whether no SAO or band or edge offset to be used may be decided by the encoder with e.g. rate distortion optimization (RDO) and signaled to the decoder. In the band offset, the whole range of sample values is in certain cases divided into 32 equal-width bands. For example, for 8-bit samples, width of a band is 8 (=256/32). Out of 32 bands, 4 of them are selected and different offsets are signalled for each of the selected bands. The selection decision is made by the encoder and may be signalled as follows: The index of the first band is signalled and then it is inferred that the following four bands are the chosen ones. The band offset may be useful in correcting errors in smooth regions. In the edge offset type, the edge offset (EO) type may be chosen out of four possible types (or edge classifications) where each type is associated with a direction: 1) vertical, 2) horizontal, 3) 135 degrees diagonal, and 4) 45 degrees diagonal. The choice of the direction is given by the encoder and signalled to the decoder. Each type defines the location of two neighbour samples for a given sample based on the angle. Then each sample in the CTU is classified into one of five categories based on comparison of the sample value against the values of the two neighbour samples. The five categories are described as follows:1. Current sample value is smaller than the two neighbour sample2. Current ample value is smaller than one of the neighbors and equal to the other neighbor3. Current sample value is greater than one of the neighbors and equal to the other neighbor4. Current sample value is greater than two neighbour samples5. None of the above These five categories are not required to be signalled to the decoder because the classification is based on only reconstructed samples, which may be available and identical in both the encoder and decoder. After each sample in an edge offset type CTU is classified as one of the five categories, an offset value for each of the first four categories is determined and signalled to the decoder. The offset for each category is added to the sample values associated with the corresponding category. Edge offsets may be effective in correcting ringing artifacts. The SAO parameters may be signalled as interleaved in CTU data. Above CTU, slice header contains a syntax element specifying whether SAO is used in the slice. If SAO is used, then two additional syntax elements specify whether SAO is applied to Cb and Cr components. For each CTU, there are three options: 1) copying SAO parameters from the left CTU, 2) copying SAO parameters from the above CTU, or 3) signalling new SAO parameters. The adaptive loop filter (ALF) is another method to enhance quality of the reconstructed samples. This may be achieved by filtering the sample values in the loop. The encoder may determine which region of the pictures are to be filtered and the filter coefficients based on e.g. RDO and this information is signalled to the decoder. In typical video codecs the motion information is indicated with motion vectors associated with each motion compensated image block. Each of these motion vectors represents the displacement of the image block in the picture to be coded (in the encoder side) or decoded (in the decoder side) and the prediction source block in one of the previously coded or decoded pictures. In order to represent motion vectors efficiently those are typically coded differentially with respect to block specific predicted motion vectors. In typical video codecs the predicted motion vectors are created in a predefined way, for example calculating the median of the encoded or decoded motion vectors of the adjacent blocks. Another way to create motion vector predictions is to generate a list of candidate predictions from adjacent blocks and/or co-located blocks in temporal reference pictures and signalling the chosen candidate as the motion vector predictor. In addition to predicting the motion vector values, it can be predicted which reference picture(s) are used for motion-compensated prediction and this prediction information may be represented for example by a reference index of previously coded/decoded picture. The reference index is typically predicted from adjacent blocks and/or or co-located blocks in temporal reference picture. Moreover, typical high efficiency video codecs employ an additional motion information coding/decoding mechanism, often called merging/merge mode, where all the motion field information, which includes motion vector and corresponding reference picture index for each available reference picture list, is predicted and used without any modification correction. Similarly, predicting the motion field information is carried out using the motion field information of adjacent blocks and/or co-located blocks in temporal reference pictures and the used motion field information is signalled among a list of motion field candidate list filled with motion field information of available adjacent/co-located blocks. Typical video codecs enable the use of uni-prediction, where a single prediction block is used for a block being (de)coded, and bi-prediction, where two prediction blocks are combined to form the prediction for a block being (de)coded. Some video codecs enable weighted prediction, where the sample values of the prediction blocks are weighted prior to adding residual information. For example, multiplicative weighting factor and an additive offset which can be applied. In explicit weighted prediction, enabled by some video codecs, a weighting factor and offset may be coded for example in the slice header for each allowable reference picture index. In implicit weighted prediction, enabled by some video codecs, the weighting factors and/or offsets are not coded but are derived e.g. based on the relative picture order count (POC) distances of the reference pictures. In typical video codecs the prediction residual after motion compensation is first transformed with a transform kernel (like DCT) and then coded. The reason for this is that often there still exists some correlation among the residual and transform can in many cases help reduce this correlation and provide more efficient coding. Typical video encoders utilize Lagrangian cost functions to find optimal coding modes. e.g. the desired Macroblock mode and associated motion vectors. This kind of cost function uses a weighting factor λ to tie together the (exact or estimated) image distortion due to lossy coding methods and the (exact or estimated) amount of information that is required to represent the pixel values in an image area: C=D+λR, (1) where C is the Lagrangian cost to be minimized, D is the image distortion (e.g. Mean Squared Error) with the mode and motion vectors considered, and R the number of bits needed to represent the required data to reconstruct the image block in the decoder (including the amount of data to represent the candidate motion vectors). Video coding standards and specifications may allow encoders to divide a coded picture to coded slices or alike. In-picture prediction is typically disabled across slice boundaries. Thus, slices can be regarded as a way to split a coded picture to independently decodable pieces. In H.264/AVC and HEVC, in-picture prediction may be disabled across slice boundaries. Thus, slices can be regarded as a way to split a coded picture into independently decodable pieces, and slices are therefore often regarded as elementary units for transmission. In many cases, encoders may indicate in the bitstream which types of in-picture prediction are turned off across slice boundaries, and the decoder operation takes this information into account for example when concluding which prediction sources are available. For example, samples from a neighboring macroblock or CU may be regarded as unavailable for intra prediction, if the neighboring macroblock or CU resides in a different slice. An elementary unit for the output of an H.264/AVC or HEVC encoder and the input of an H.264/AVC or HEVC decoder, respectively, is a Network Abstraction Layer (NAL) unit. For transport over packet-oriented networks or storage into structured files, NAL units may be encapsulated into packets or similar structures. A bytestream format has been specified in H.264/AVC and HEVC for transmission or storage environments that do not provide framing structures. The bytestream format separates NAL units from each other by attaching a start code in front of each NAL unit. To avoid false detection of NAL unit boundaries, encoders run a byte-oriented start code emulation prevention algorithm, which adds an emulation prevention byte to the NAL unit payload if a start code would have occurred otherwise. In order to enable straightforward gateway operation between packet- and stream-oriented systems, start code emulation prevention may always be performed regardless of whether the bytestream format is in use or not. A NAL unit may be defined as a syntax structure containing an indication of the type of data to follow and bytes containing that data in the form of an RBSP interspersed as necessary with emulation prevention bytes. A raw byte sequence payload (RBSP) may be defined as a syntax structure containing an integer number of bytes that is encapsulated in a NAL unit. An RBSP is either empty or has the form of a string of data bits containing syntax elements followed by an RBSP stop bit and followed by zero or more subsequent bits equal to 0. NAL units consist of a header and payload. In H.264/AVC and HEVC, the NAL unit header indicates the type of the NAL unit. In H.264/AVC, the NAL unit header indicates whether a coded slice contained in the NAL unit is a part of a reference picture or a non-reference picture. H.264/AVC NAL unit header includes a 2-bit nal_ref_idc syntax element, which when equal to 0 indicates that a coded slice contained in the NAL unit is a part of a non-reference picture and when greater than 0 indicates that a coded slice contained in the NAL unit is a part of a reference picture. The header for SVC and MVC NAL units may additionally contain various indications related to the scalability and multiview hierarchy. In HEVC, a two-byte NAL unit header is used for all specified NAL unit types. The NAL unit header contains one reserved bit, a six-bit NAL unit type indication, a three-bit nuh_temporal_id_plus1 indication for temporal level (may be required to be greater than or equal to 1) and a six-bit reserved field (called nuh_layer_id). The temporal id_plus1 syntax element may be regarded as a temporal identifier for the NAL unit, and a zero-based TemporalId variable may be derived as follows: TemporalId=temporal_id_plus1-1. TemporalId equal to 0 corresponds to the lowest temporal level. The value of temporal_id_plus1 is required to be non-zero in order to avoid start code emulation involving the two NAL unit header bytes. The bitstream created by excluding all VCL NAL units having a TemporalId greater than or equal to a selected value and including all other VCL NAL units remains conforming Consequently, a picture having TemporalId equal to TID does not use any picture having a TemporalId greater than TID as inter prediction reference. A sub-layer or a temporal sub-layer may be defined to be a temporal scalable layer of a temporal scalable bitstream, consisting of VCL NAL units with a particular value of the TemporalId variable and the associated non-VCL NAL units. The six-bit reserved field (nuh_layer_id) is expected to be used by extensions such as a future scalable and 3D video extension. It is expected that these six bits would carry information on the scalability hierarchy. Without loss of generality, in some example embodiments embodiments a variable LayerId is derived from the value of nuh_layer_id for example as follows: LayerId=nuh_layer_id. In the following, layer identifier, LayerId, nuh_layer_id and layer_id are used interchangeably unless otherwise indicated. NAL units can be categorized into Video Coding Layer (VCL) NAL units and non-VCL NAL units. VCL NAL units are typically coded slice NAL units. In H.264/AVC, coded slice NAL units contain syntax elements representing one or more coded macroblocks, each of which corresponds to a block of samples in the uncompressed picture. In HEVC, coded slice NAL units contain syntax elements representing one or more CU. In H.264/AVC, a coded slice NAL unit can be indicated to be a coded slice in an Instantaneous Decoding Refresh (IDR) picture or coded slice in a non-IDR picture. In HEVC, a coded slice NAL unit can be indicated to be one of the following types: Name ofContent of NAL unit andnal_unit_typenal_unit_typeRBSP syntax structure0,TRAIL_N,Coded slice segment of a non-1TRAIL_RTSA, non-STSA trailing pictureslice_segment_layer_rbsp( )2,TSA_N,Coded slice segment of a TSA3TSA_Rpictureslice_segment_layer_rbsp( )4,STSA_N,Coded slice segment of an STSA5STSA_Rpictureslice_layer_rbsp( )6,RADL_N,Coded slice segment of a RADL7RADL_Rpictureslice_layer_rbsp( )8,RASL_N,Coded slice segment of a RASL9RASL_R,pictureslice_layer_rbsp( )10,RSV_VCL_N10Reserved // reserved non-RAP12,RSV_VCL_N12non-reference VCL NAL unit14RSV_VCL_N14types11,RSV_VCL_R11Reserved // reserved non-RAP13,RSV_VCL_R13reference VCL NAL unit types15RSV_VCL_R1516,BLA_W_LPCoded slice segment of a BLA17,BLA_W_DLP (a.k.a.picture18IDR_W_RADL)slice_segment_layer_rbsp( )BLA_N_LP19,IDR_W_DLP (a.k.a.Coded slice segment of an IDR20IDR_W_RADL)pictureIDR_N_LPslice_segment_layer_rbsp( )21CRA_NUTCoded slice segment of a CRApictureslice_segment_layer_rbsp( )22,RSV_IRAP_VCL22Reserved // reserved RAP VCL23. . .NAL unit typesRSV_IRAP_VCL2324 . . . 31RSV_VCL24 . . .Reserved // reserved non-RAPRSV_VCL31VCL NAL unit types In HEVC, abbreviations for picture types may be defined as follows: trailing (TRAIL) picture, Temporal Sub-layer Access (TSA), Step-wise Temporal Sub-layer Access (STSA), Random Access Decodable Leading (RADL) picture, Random Access Skipped Leading (RASL) picture, Broken Link Access (BLA) picture, Instantaneous Decoding Refresh (IDR) picture, Clean Random Access (CRA) picture. A Random Access Point (RAP) picture, which may also be referred to as an intra random access point (IRAP) picture, is a picture where each slice or slice segment has nal_unit_type in the range of 16 to 23, inclusive. A RAP picture contains only intra-coded slices, and may be a BLA picture, a CRA picture or an IDR picture. The first picture in the bitstream is a RAP picture. Provided the necessary parameter sets are available when they need to be activated, the RAP picture and all subsequent non-RASL pictures in decoding order can be correctly decoded without performing the decoding process of any pictures that precede the RAP picture in decoding order. There may be pictures in a bitstream that contain only intra-coded slices that are not RAP pictures. In HEVC a CRA picture may be the first picture in the bitstream in decoding order, or may appear later in the bitstream. CRA pictures in HEVC allow so-called leading pictures that follow the CRA picture in decoding order but precede it in output order. Some of the leading pictures, so-called RASL pictures, may use pictures decoded before the CRA picture as a reference. Pictures that follow a CRA picture in both decoding and output order are decodable if random access is performed at the CRA picture, and hence clean random access is achieved similarly to the clean random access functionality of an IDR picture. A CRA picture may have associated RADL or RASL pictures. When a CRA picture is the first picture in the bitstream in decoding order, the CRA picture is the first picture of a coded video sequence in decoding order, and any associated RASL pictures are not output by the decoder and may not be decodable, as they may contain references to pictures that are not present in the bitstream. A leading picture is a picture that precedes the associated RAP picture in output order. The associated RAP picture is the previous RAP picture in decoding order (if present). A leading picture is either a RADL picture or a RASL picture. All RASL pictures are leading pictures of an associated BLA or CRA picture. When the associated RAP picture is a BLA picture or is the first coded picture in the bitstream, the RASL picture is not output and may not be correctly decodable, as the RASL picture may contain references to pictures that are not present in the bitstream. However, a RASL picture can be correctly decoded if the decoding had started from a RAP picture before the associated RAP picture of the RASL picture. RASL pictures are not used as reference pictures for the decoding process of non-RASL pictures. When present, all RASL pictures precede, in decoding order, all trailing pictures of the same associated RAP picture. In some drafts of the HEVC standard, a RASL picture was referred to a Tagged for Discard (TFD) picture. All RADL pictures are leading pictures. RADL pictures are not used as reference pictures for the decoding process of trailing pictures of the same associated RAP picture. When present, all RADL pictures precede, in decoding order, all trailing pictures of the same associated RAP picture. RADL pictures do not refer to any picture preceding the associated RAP picture in decoding order and can therefore be correctly decoded when the decoding starts from the associated RAP picture. In some drafts of the HEVC standard, a RADL picture was referred to a Decodable Leading Picture (DLP). When a part of a bitstream starting from a CRA picture is included in another bitstream, the RASL pictures associated with the CRA picture might not be correctly decodable, because some of their reference pictures might not be present in the combined bitstream. To make such a splicing operation straightforward, the NAL unit type of the CRA picture can be changed to indicate that it is a BLA picture. The RASL pictures associated with a BLA picture may not be correctly decodable hence are not be output/displayed. Furthermore, the RASL pictures associated with a BLA picture may be omitted from decoding. A BLA picture may be the first picture in the bitstream in decoding order, or may appear later in the bitstream. Each BLA picture begins a new coded video sequence, and has similar effect on the decoding process as an IDR picture. However, a BLA picture contains syntax elements that specify a non-empty reference picture set. When a BLA picture has nal_unit_type equal to BLA_W_LP, it may have associated RASL pictures, which are not output by the decoder and may not be decodable, as they may contain references to pictures that are not present in the bitstream. When a BLA picture has nal_unit_type equal to BLA_W_LP, it may also have associated RADL pictures, which are specified to be decoded. When a BLA picture has nal_unit_type equal to BLA_W_DLP, it does not have associated RASL pictures but may have associated RADL pictures, which are specified to be decoded. When a BLA picture has nal_unit_type equal to BLA_N_LP, it does not have any associated leading pictures. An IDR picture having nal_unit_type equal to IDR_N_LP does not have associated leading pictures present in the bitstream. An IDR picture having nal_unit_type equal to IDR_W_LP does not have associated RASL pictures present in the bitstream, but may have associated RADL pictures in the bitstream. When the value of nal_unit_type is equal to TRAIL_N, TSA_N, STSA_N, RADL_N, RASL_N, RSV_VCL_N10, RSV_VCL_N12, or RSV_VCL_N14, the decoded picture is not used as a reference for any other picture of the same temporal sub-layer. That is, in HEVC, when the value of nal_unit_type is equal to TRAIL_N, TSA_N, STSA_N, RADL_N, RASL_N, RSV_VCL_N10, RSV_VCL_N12, or RSV_VCL_N14, the decoded picture is not included in any of RefPicSetStCurrBefore, RefPicSetStCurrAfter and RefPicSetLtCurr of any picture with the same value of TemporalId. A coded picture with nal_unit_type equal to TRAIL_N, TSA_N, STSA_N, RADL_N, RASL_N, RSV_VCL_N10, RSV_VCL_N12, or RSV_VCL_N14may be discarded without affecting the decodability of other pictures with the same value of TemporalId. A trailing picture may be defined as a picture that follows the associated RAP picture in output order. Any picture that is a trailing picture does not have nal_unit_type equal to RADL_N, RADL_R, RASL_N or RASL_R. Any picture that is a leading picture may be constrained to precede, in decoding order, all trailing pictures that are associated with the same RAP picture. No RASL pictures are present in the bitstream that are associated with a BLA picture having nal_unit_type equal to BLA_W_DLP or BLA_N_LP. No RADL pictures are present in the bitstream that are associated with a BLA picture having nal_unit_type equal to BLA_N_LP or that are associated with an IDR picture having nal_unit_type equal to IDR_N_LP. Any RASL picture associated with a CRA or BLA picture may be constrained to precede any RADL picture associated with the CRA or BLA picture in output order. Any RASL picture associated with a CRA picture may be constrained to follow, in output order, any other RAP picture that precedes the CRA picture in decoding order. In HEVC there are two picture types, the TSA and STSA picture types that can be used to indicate temporal sub-layer switching points. If temporal sub-layers with TemporalId up to N had been decoded until the TSA or STSA picture (exclusive) and the TSA or STSA picture has TemporalId equal to N+1, the TSA or STSA picture enables decoding of all subsequent pictures (in decoding order) having TemporalId equal to N+1. The TSA picture type may impose restrictions on the TSA picture itself and all pictures in the same sub-layer that follow the TSA picture in decoding order. None of these pictures is allowed to use inter prediction from any picture in the same sub-layer that precedes the TSA picture in decoding order. The TSA definition may further impose restrictions on the pictures in higher sub-layers that follow the TSA picture in decoding order. None of these pictures is allowed to refer a picture that precedes the TSA picture in decoding order if that picture belongs to the same or higher sub-layer as the TSA picture. TSA pictures have TemporalId greater than 0. The STSA is similar to the TSA picture but does not impose restrictions on the pictures in higher sub-layers that follow the STSA picture in decoding order and hence enable up-switching only onto the sub-layer where the STSA picture resides. A non-VCL NAL unit may be for example one of the following types: a sequence parameter set, a picture parameter set, a supplemental enhancement information (SEI) NAL unit, an access unit delimiter, an end of sequence NAL unit, an end of stream NAL unit, or a filler data NAL unit. Parameter sets may be needed for the reconstruction of decoded pictures, whereas many of the other non-VCL NAL units are not necessary for the reconstruction of decoded sample values. Parameters that remain unchanged through a coded video sequence may be included in a sequence parameter set. In addition to the parameters that may be needed by the decoding process, the sequence parameter set may optionally contain video usability information (VUI), which includes parameters that may be important for buffering, picture output timing, rendering, and resource reservation. There are three NAL units specified in H.264/AVC to carry sequence parameter sets: the sequence parameter set NAL unit containing all the data for H.264/AVC VCL NAL units in the sequence, the sequence parameter set extension NAL unit containing the data for auxiliary coded pictures, and the subset sequence parameter set for MVC and SVC VCL NAL units. In HEVC a sequence parameter set RBSP includes parameters that can be referred to by one or more picture parameter set RBSPs or one or more SEI NAL units containing a buffering period SEI message. A picture parameter set contains such parameters that are likely to be unchanged in several coded pictures. A picture parameter set RBSP may include parameters that can be referred to by the coded slice NAL units of one or more coded pictures. In a draft HEVC standard, there was also a third type of parameter sets, here referred to as an Adaptation Parameter Set (APS), which includes parameters that are likely to be unchanged in several coded slices but may change for example for each picture or each few pictures. In a draft HEVC, the APS syntax structure includes parameters or syntax elements related to quantization matrices (QM), adaptive sample offset (SAO), adaptive loop filtering (ALF), and deblocking filtering. In a draft HEVC, an APS is a NAL unit and coded without reference or prediction from any other NAL unit. An identifier, referred to as aps_id syntax element, is included in APS NAL unit, and included and used in the slice header to refer to a particular APS. In another draft HEVC standard. an APS syntax structure only contains ALF parameters. In a draft HEVC standard, an adaptation parameter set RBSP includes parameters that can be referred to by the coded slice NAL units of one or more coded pictures when at least one of sample_adaptive_offset_enabled_flag or adaptive_loop_filter_enabled_flag are equal to 1. In the final published HEVC, the APS syntax structure was removed from the specification text. In HEVC, a video parameter set (VPS) may be defined as a syntax structure containing syntax elements that apply to zero or more entire coded video sequences as determined by the content of a syntax element found in the SPS referred to by a syntax element found in the PPS referred to by a syntax element found in each slice segment header. A video parameter set RBSP may include parameters that can be referred to by one or more sequence parameter set RBSPs. The relationship and hierarchy between video parameter set (VPS), sequence parameter set (SPS), and picture parameter set (PPS) may be described as follows. VPS resides one level above SPS in the parameter set hierarchy and in the context of scalability and/or 3D video. VPS may include parameters that are common for all slices across all (scalability or view) layers in the entire coded video sequence. SPS includes the parameters that are common for all slices in a particular (scalability or view) layer in the entire coded video sequence, and may be shared by multiple (scalability or view) layers. PPS includes the parameters that are common for all slices in a particular layer representation (the representation of one scalability or view layer in one access unit) and are likely to be shared by all slices in multiple layer representations. VPS may provide information about the dependency relationships of the layers in a bitstream, as well as many other information that are applicable to all slices across all (scalability or view) layers in the entire coded video sequence. H.264/AVC and HEVC syntax allows many instances of parameter sets, and each instance is identified with a unique identifier. In order to limit the memory usage needed for parameter sets, the value range for parameter set identifiers has been limited. In H.264/AVC and HEVC, each slice header includes the identifier of the picture parameter set that is active for the decoding of the picture that contains the slice, and each picture parameter set contains the identifier of the active sequence parameter set. In a draft HEVC standard, a slice header additionally contains an APS identifier, although in the published HEVC standard the APS identifier was removed from the slice header. Consequently, the transmission of picture and sequence parameter sets does not have to be accurately synchronized with the transmission of slices. Instead, it is sufficient that the active sequence and picture parameter sets are received at any moment before they are referenced, which allows transmission of parameter sets “out-of-band” using a more reliable transmission mechanism compared to the protocols used for the slice data. For example, parameter sets can be included as a parameter in the session description for Real-time Transport Protocol (RTP) sessions. If parameter sets are transmitted in-band, they can be repeated to improve error robustness. A parameter set may be activated by a reference from a slice or from another active parameter set or in some cases from another syntax structure such as a buffering period SEI message. A SEI NAL unit may contain one or more SEI messages, which are not required for the decoding of output pictures but may assist in related processes, such as picture output timing, rendering, error detection, error concealment, and resource reservation. Several SEI messages are specified in H.264/AVC and HEVC, and the user data SEI messages enable organizations and companies to specify SEI messages for their own use. H.264/AVC and HEVC contain the syntax and semantics for the specified SEI messages but no process for handling the messages in the recipient is defined. Consequently, encoders are required to follow the H.264/AVC standard or the HEVC standard when they create SEI messages, and decoders conforming to the H.264/AVC standard or the HEVC standard, respectively, are not required to process SEI messages for output order conformance. One of the reasons to include the syntax and semantics of SEI messages in H.264/AVC and HEVC is to allow different system specifications to interpret the supplemental information identically and hence interoperate. It is intended that system specifications can require the use of particular SEI messages both in the encoding end and in the decoding end, and additionally the process for handling particular SEI messages in the recipient can be specified. Several nesting SEI messages have been specified in the AVC and HEVC standards or proposed otherwise. The idea of nesting SEI messages is to contain one or more SEI messages within a nesting SEI message and provide a mechanism for associating the contained SEI messages with a subset of the bitstream and/or a subset of decoded data. It may be required that a nesting SEI message contains one or more SEI messages that are not nesting SEI messages themselves. An SEI message contained in a nesting SEI message may be referred to as a nested SEI message. An SEI message not contained in a nesting SEI message may be referred to as a non-nested SEI message. The scalable nesting SEI message of HEVC enables to identify either a bitstream subset (resulting from a sub-bitstream extraction process) or a set of layers to which the nested SEI messages apply. A bitstream subset may also be referred to as a sub-bitstream. A coded picture is a coded representation of a picture. A coded picture in H.264/AVC comprises the VCL NAL units that are required for the decoding of the picture. In H.264/AVC, a coded picture can be a primary coded picture or a redundant coded picture. A primary coded picture is used in the decoding process of valid bitstreams, whereas a redundant coded picture is a redundant representation that should only be decoded when the primary coded picture cannot be successfully decoded. In HEVC, no redundant coded picture has been specified. In H.264/AVC, an access unit (AU) comprises a primary coded picture and those NAL units that are associated with it. In H.264/AVC, the appearance order of NAL units within an access unit is constrained as follows. An optional access unit delimiter NAL unit may indicate the start of an access unit. It is followed by zero or more SEI NAL units. The coded slices of the primary coded picture appear next. In H.264/AVC, the coded slice of the primary coded picture may be followed by coded slices for zero or more redundant coded pictures. A redundant coded picture is a coded representation of a picture or a part of a picture. A redundant coded picture may be decoded if the primary coded picture is not received by the decoder for example due to a loss in transmission or a corruption in physical storage medium. In H.264/AVC, an access unit may also include an auxiliary coded picture, which is a picture that supplements the primary coded picture and may be used for example in the display process. An auxiliary coded picture may for example be used as an alpha channel or alpha plane specifying the transparency level of the samples in the decoded pictures. An alpha channel or plane may be used in a layered composition or rendering system, where the output picture is formed by overlaying pictures being at least partly transparent on top of each other. An auxiliary coded picture has the same syntactic and semantic restrictions as a monochrome redundant coded picture. In H.264/AVC, an auxiliary coded picture contains the same number of macroblocks as the primary coded picture. In HEVC, a coded picture may be defined as a coded representation of a picture containing all coding tree units of the picture. In HEVC, an access unit (AU) may be defined as a set of NAL units that are associated with each other according to a specified classification rule, are consecutive in decoding order, and contain one or more coded pictures with different values of nuh_layer_id. In addition to containing the VCL NAL units of the coded picture, an access unit may also contain non-VCL NAL units. In H.264/AVC, a coded video sequence is defined to be a sequence of consecutive access units in decoding order from an IDR access unit, inclusive, to the next IDR access unit, exclusive, or to the end of the bitstream, whichever appears earlier. In HEVC, a coded video sequence (CVS) may be defined, for example, as a sequence of access units that consists, in decoding order, of an IRAP access unit with NoRas1OutputFlag equal to 1, followed by zero or more access units that are not IRAP access units with NoRas1OutputFlag equal to 1, including all subsequent access units up to but not including any subsequent access unit that is an IRAP access unit with NoRas1OutputFlag equal to 1. An IRAP access unit may be an IDR access unit, a BLA access unit, or a CRA access unit. The value of NoRas1OutputFlag is equal to 1 for each IDR access unit, each BLA access unit, and each CRA access unit that is the first access unit in the bitstream in decoding order, is the first access unit that follows an end of sequence NAL unit in decoding order, or has HandleCraAsBlaFlag equal to 1. NoRas1OutputFlag equal to 1 has an impact that the RASL pictures associated with the IRAP picture for which the NoRas1OutputFlag is set are not output by the decoder. There may be means to provide the value of HandleCraAsBlaFlag to the decoder from an external entity, such as a player or a receiver, which may control the decoder. HandleCraAsBlaFlag may be set to 1 for example by a player that seeks to a new position in a bitstream or tunes into a broadcast and starts decoding and then starts decoding from a CRA picture. When HandleCraAsBlaFlag is equal to 1 for a CRA picture, the CRA picture is handled and decoded as if it were a BLA picture. A Structure of Pictures (SOP) may be defined as one or more coded pictures consecutive in decoding order, in which the first coded picture in decoding order is a reference picture at the lowest temporal sub-layer and no coded picture except potentially the first coded picture in decoding order is a RAP picture. All pictures in the previous SOP precede in decoding order all pictures in the current SOP and all pictures in the next SOP succeed in decoding order all pictures in the current SOP. A SOP may represent a hierarchical and repetitive inter prediction structure. The term group of pictures (GOP) may sometimes be used interchangeably with the term SOP and having the same semantics as the semantics of SOP. The bitstream syntax of H.264/AVC and HEVC indicates whether a particular picture is a reference picture for inter prediction of any other picture. Pictures of any coding type (I, P, B) can be reference pictures or non-reference pictures in H.264/AVC and HEVC. H.264/AVC specifies the process for decoded reference picture marking in order to control the memory consumption in the decoder. The maximum number of reference pictures used for inter prediction, referred to as M, is determined in the sequence parameter set. When a reference picture is decoded, it is marked as “used for reference”. If the decoding of the reference picture caused more than M pictures marked as “used for reference”, at least one picture is marked as “unused for reference”. There are two types of operation for decoded reference picture marking: adaptive memory control and sliding window. The operation mode for decoded reference picture marking is selected on picture basis. The adaptive memory control enables explicit signaling which pictures are marked as “unused for reference” and may also assign long-term indices to short-term reference pictures. The adaptive memory control may require the presence of memory management control operation (MMCO) parameters in the bitstream. MMCO parameters may be included in a decoded reference picture marking syntax structure. If the sliding window operation mode is in use and there are M pictures marked as “used for reference”, the short-term reference picture that was the first decoded picture among those short-term reference pictures that are marked as “used for reference” is marked as “unused for reference”. In other words, the sliding window operation mode results into first-in-first-out buffering operation among short-term reference pictures. One of the memory management control operations in H.264/AVC causes all reference pictures except for the current picture to be marked as “unused for reference”. An instantaneous decoding refresh (IDR) picture contains only intra-coded slices and causes a similar “reset” of reference pictures. In HEVC, reference picture marking syntax structures and related decoding processes are not used, but instead a reference picture set (RPS) syntax structure and decoding process are used instead for a similar purpose. A reference picture set valid or active for a picture includes all the reference pictures used as reference for the picture and all the reference pictures that are kept marked as “used for reference” for any subsequent pictures in decoding order. There are six subsets of the reference picture set, which are referred to as namely RefPicSetStCurr0(a.k.a. RefPicSetStCurrBefore), RefPicSetStCurr1(a.k.a. RefPicSetStCurrAfter), RefPicSetStFoll0, RefPicSetStFoll1, RefPicSetLtCurr, and RefPicSetLtFoll. RefPicSetStFoll0and RefPicSetStFoll1may also be considered to form jointly one subset RefPicSetStFoll. The notation of the six subsets is as follows. “Curr” refers to reference pictures that are included in the reference picture lists of the current picture and hence may be used as inter prediction reference for the current picture. “Foll” refers to reference pictures that are not included in the reference picture lists of the current picture but may be used in subsequent pictures in decoding order as reference pictures. “St” refers to short-term reference pictures, which may generally be identified through a certain number of least significant bits of their POC value. “Lt” refers to long-term reference pictures, which are specifically identified and generally have a greater difference of POC values relative to the current picture than what can be represented by the mentioned certain number of least significant bits. “0” refers to those reference pictures that have a smaller POC value than that of the current picture. “1” refers to those reference pictures that have a greater POC value than that of the current picture. RefPicSetStCurr0, RefPicSetStCurr1, RefPicSetStFoll0and RefPicSetStFoll1are collectively referred to as the short-term subset of the reference picture set. RefPicSetLtCurr and RefPicSetLtFoll are collectively referred to as the long-term subset of the reference picture set. In HEVC, a reference picture set may be specified in a sequence parameter set and taken into use in the slice header through an index to the reference picture set. A reference picture set may also be specified in a slice header. A long-term subset of a reference picture set is generally specified only in a slice header, while the short-term subsets of the same reference picture set may be specified in the picture parameter set or slice header. A reference picture set may be coded independently or may be predicted from another reference picture set (known as inter-RPS prediction). When a reference picture set is independently coded, the syntax structure includes up to three loops iterating over different types of reference pictures; short-term reference pictures with lower POC value than the current picture, short-term reference pictures with higher POC value than the current picture and long-term reference pictures. Each loop entry specifies a picture to be marked as “used for reference”. In general, the picture is specified with a differential POC value. The inter-RPS prediction exploits the fact that the reference picture set of the current picture can be predicted from the reference picture set of a previously decoded picture. This is because all the reference pictures of the current picture are either reference pictures of the previous picture or the previously decoded picture itself. It is only necessary to indicate which of these pictures should be reference pictures and be used for the prediction of the current picture. In both types of reference picture set coding, a flag (used_by_curr_pic_X_flag) is additionally sent for each reference picture indicating whether the reference picture is used for reference by the current picture (included in a *Curr list) or not (included in a *Foll list). Pictures that are included in the reference picture set used by the current slice are marked as “used for reference”, and pictures that are not in the reference picture set used by the current slice are marked as “unused for reference”. If the current picture is an IDR picture, RefPicSetStCurr0, RefPicSetStCurr1, RefPicSetStFoll0, RefPicSetStFoll1, RefPicSetLtCurr, and RefPicSetLtFoll are all set to empty. A Decoded Picture Buffer (DPB) may be used in the encoder and/or in the decoder. There are two reasons to buffer decoded pictures, for references in inter prediction and for reordering decoded pictures into output order. As H.264/AVC and HEVC provide a great deal of flexibility for both reference picture marking and output reordering, separate buffers for reference picture buffering and output picture buffering may waste memory resources. Hence, the DPB may include a unified decoded picture buffering process for reference pictures and output reordering. A decoded picture may be removed from the DPB when it is no longer used as a reference and is not needed for output. In many coding modes of H.264/AVC and HEVC, the reference picture for inter prediction is indicated with an index to a reference picture list. The index may be coded with variable length coding, which usually causes a smaller index to have a shorter value for the corresponding syntax element. In H.264/AVC and HEVC, two reference picture lists (reference picture list 0 and reference picture list 1) are generated for each bi-predictive (B) slice, and one reference picture list (reference picture list 0) is formed for each inter-coded (P) slice. A reference picture list, such as reference picture list 0 and reference picture list 1, is typically constructed in two steps: First, an initial reference picture list is generated. The initial reference picture list may be generated for example on the basis of frame_num, POC, temporal_id (or TemporalID or alike), or information on the prediction hierarchy such as GOP structure, or any combination thereof. Second, the initial reference picture list may be reordered by reference picture list reordering (RPLR) commands, also known as reference picture list modification syntax structure, which may be contained in slice headers. In H.264/AVC, the RPLR commands indicate the pictures that are ordered to the beginning of the respective reference picture list. This second step may also be referred to as the reference picture list modification process, and the RPLR commands may be included in a reference picture list modification syntax structure. If reference picture sets are used. the reference picture list 0 may be initialized to contain RefPicSetStCurr0first, followed by RefPicSetStCurr1, followed by RefPicSetLtCurr. Reference picture list 1 may be initialized to contain RefPicSetStCurr1first, followed by RefPicSetStCurr0. In HEVC, the initial reference picture lists may be modified through the reference picture list modification syntax structure, where pictures in the initial reference picture lists may be identified through an entry index to the list. In other words. in HEVC, reference picture list modification is encoded into a syntax structure comprising a loop over each entry in the final reference picture list, where each loop entry is a fixed-length coded index to the initial reference picture list and indicates the picture in ascending position order in the final reference picture list. Many coding standards, including H.264/AVC and HEVC, may have decoding process to derive a reference picture index to a reference picture list, which may be used to indicate which one of the multiple reference pictures is used for inter prediction for a particular block. A reference picture index may be coded by an encoder into the bitstream is some inter coding modes or it may be derived (by an encoder and a decoder) for example using neighboring blocks in some other inter coding modes. In order to represent motion vectors efficiently in bitstreams, motion vectors may be coded differentially with respect to a block-specific predicted motion vector. In many video codecs, the predicted motion vectors are created in a predefined way, for example by calculating the median of the encoded or decoded motion vectors of the adjacent blocks. Another way to create motion vector predictions, sometimes referred to as advanced motion vector prediction (AMVP), is to generate a list of candidate predictions from adjacent blocks and/or co-located blocks in temporal reference pictures and signalling the chosen candidate as the motion vector predictor. In addition to predicting the motion vector values, the reference index of previously coded/decoded picture can be predicted. The reference index is typically predicted from adjacent blocks and/or co-located blocks in temporal reference picture. Differential coding of motion vectors is typically disabled across slice boundaries. The advanced motion vector prediction (AMVP) or alike may operate for example as follows, while other similar realizations of advanced motion vector prediction are also possible for example with different candidate position sets and candidate locations with candidate position sets. Two spatial motion vector predictors (MVPs) may be derived and a temporal motion vector predictor (TMVP) may be derived. They may be selected among the positions shown inFIG.6: three spatial motion vector predictor candidate positions603,604,605located above the current prediction block600(B0, B1, B2) and two601,602on the left (A0, A1). The first motion vector predictor that is available (e.g. resides in the same slice, is inter-coded, etc.) in a pre-defined order of each candidate position set, (B0, B1, B2) or (A0, A1), may be selected to represent that prediction direction (up or left) in the motion vector competition. A reference index for the temporal motion vector predictor may be indicated by the encoder in the slice header (e.g. as a collocated_ref_idx syntax element). The motion vector obtained from the co-located picture may be scaled according to the proportions of the picture order count differences of the reference picture of the temporal motion vector predictor, the colocated picture, and the current picture. Moreover, a redundancy check may be performed among the candidates to remove identical candidates, which can lead to the inclusion of a zero motion vector in the candidate list. The motion vector predictor may be indicated in the bitstream for example by indicating the direction of the spatial motion vector predictor (up or left) or the selection of the temporal motion vector predictor candidate. Many high efficiency video codecs such as HEVC codec employ an additional motion information coding/decoding mechanism, often called merging/merge mode/process/mechanism, where all the motion information of a block/PU is predicted and used without any modification/correction. The aforementioned motion information for a PU may comprise one or more of the following: 1) The information whether ‘the PU is uni-predicted using only reference picture list0’ or ‘the PU is uni-predicted using only reference picture list1’ or ‘the PU is bi-predicted using both reference picture list0 and list1 ’; 2) Motion vector value corresponding to the reference picture list0, which may comprise a horizontal and vertical motion vector component; 3) Reference picture index in the reference picture list0 and/or an identifier of a reference picture pointed to by the motion vector corresponding to reference picture list0, where the identifier of a reference picture may be for example a picture order count value, a layer identifier value (for inter-layer prediction), or a pair of a picture order count value and a layer identifier value; 4) Information of the reference picture marking of the reference picture, e.g. information whether the reference picture was marked as “used for short-term reference” or “used for long-term reference”; 5)-7) The same as 2)-4), respectively, but for reference picture list1. Similarly, predicting the motion information is carried out using the motion information of adjacent blocks and/or co-located blocks in temporal reference pictures. A list, often called as a merge list, may be constructed by including motion prediction candidates associated with available adjacent/co-located blocks and the index of selected motion prediction candidate in the list is signalled and the motion information of the selected candidate is copied to the motion information of the current PU. When the merge mechanism is employed for a whole CU and the prediction signal for the CU is used as the reconstruction signal, i.e. prediction residual is not processed, this type of coding/decoding the CU is typically named as skip mode or merge based skip mode. In addition to the skip mode, the merge mechanism may also be employed for individual PUs (not necessarily the whole CU as in skip mode) and in this case, prediction residual may be utilized to improve prediction quality. This type of prediction mode is typically named as an inter-merge mode. One of the candidates in the merge list may be a TMVP candidate, which may be derived from the collocated block within an indicated or inferred reference picture, such as the reference picture indicated for example in the slice header for example using the collocated_ref_idx syntax element or alike In HEVC the so-called target reference index for temporal motion vector prediction in the merge list is set as 0 when the motion coding mode is the merge mode. When the motion coding mode in HEVC utilizing the temporal motion vector prediction is the advanced motion vector prediction mode, the target reference index values are explicitly indicated (e.g. per each PU). When the target reference index value has been determined, the motion vector value of the temporal motion vector prediction may be derived as follows: Motion vector at the block that is co-located with the bottom-right neighbor of the current prediction unit is calculated. The picture where the co-located block resides may be e.g. determined according to the signalled reference index in the slice header as described above. The determined motion vector at the co-located block is scaled with respect to the ratio of a first picture order count difference and a second picture order count difference. The first picture order count difference is derived between the picture containing the co-located block and the reference picture of the motion vector of the co-located block. The second picture order count difference is derived between the current picture and the target reference picture. If one but not both of the target reference picture and the reference picture of the motion vector of the co-located block is a long-term reference picture (while the other is a short-term reference picture), the TMVP candidate may be considered unavailable. If both of the target reference picture and the reference picture of the motion vector of the co-located block are long-term reference pictures, no POC-based motion vector scaling may be applied. Scalable video coding may refer to coding structure where one bitstream can contain multiple representations of the content, for example, at different bitrates, resolutions or frame rates. In these cases the receiver can extract the desired representation depending on its characteristics (e.g. resolution that matches best the display device). Alternatively, a server or a network element can extract the portions of the bitstream to be transmitted to the receiver depending on e.g. the network characteristics or processing capabilities of the receiver. A scalable bitstream typically consists of a “base layer” providing the lowest quality video available and one or more enhancement layers that enhance the video quality when received and decoded together with the lower layers. In order to improve coding efficiency for the enhancement layers, the coded representation of that layer typically depends on the lower layers. E.g. the motion and mode information of the enhancement layer can be predicted from lower layers. Similarly the pixel data of the lower layers can be used to create prediction for the enhancement layer. In some scalable video coding schemes, a video signal can be encoded into a base layer and one or more enhancement layers. An enhancement layer may enhance, for example, the temporal resolution (i.e., the frame rate), the spatial resolution, or simply the quality of the video content represented by another layer or part thereof. Each layer together with all its dependent layers is one representation of the video signal, for example, at a certain spatial resolution, temporal resolution and quality level. In this document, we refer to a scalable layer together with all of its dependent layers as a “scalable layer representation”. The portion of a scalable bitstream corresponding to a scalable layer representation can be extracted and decoded to produce a representation of the original signal at certain fidelity. Scalability modes or scalability dimensions may include but are not limited to the following:Quality scalability: Base layer pictures are coded at a lower quality than enhancement layer pictures, which may be achieved for example using a greater quantization parameter value (i.e., a greater quantization step size for transform coefficient quantization) in the base layer than in the enhancement layer. Quality scalability may be further categorized into fine-grain or fine-granularity scalability (FGS), medium-grain or medium-granularity scalability (MGS), and/or coarse-grain or coarse-granularity scalability (CGS), as described below.Spatial scalability: Base layer pictures are coded at a lower resolution (i.e. have fewer samples) than enhancement layer pictures. Spatial scalability and quality scalability, particularly its coarse-grain scalability type, may sometimes be considered the same type of scalability.Bit-depth scalability: Base layer pictures are coded at lower bit-depth (e.g. 8 bits) than enhancement layer pictures (e.g. 10 or 12 bits).Chroma format scalability: Base layer pictures provide lower spatial resolution in chroma sample arrays (e.g. coded in 4:2:0 chroma format) than enhancement layer pictures (e.g. 4:4:4 format).Color gamut scalability: enhancement layer pictures have a richer/broader color representation range than that of the base layer pictures—for example the enhancement layer may have UHDTV (ITU-R BT.2020) color gamut and the base layer may have the ITU-R BT.709 color gamut.View scalability, which may also be referred to as multiview coding. The base layer represents a first view, whereas an enhancement layer represents a second view.Depth scalability, which may also be referred to as depth-enhanced coding. A layer or some layers of a bitstream may represent texture view(s), while other layer or layers may represent depth view(s).Region-of-interest scalability (as described below).Interlaced-to-progressive scalability (also known as field-to-frame scalability): coded interlaced source content material of the base layer is enhanced with an enhancement layer to represent progressive source content. The coded interlaced source content in the base layer may comprise coded fields, coded frames representing field pairs, or a mixture of them. In the interlace-to-progressive scalability, the base-layer picture may be resampled so that it becomes a suitable reference picture for one or more enhancement-layer pictures.Hybrid codec scalability (also known as coding standard scalability): In hybrid codec scalability, the bitstream syntax, semantics and decoding process of the base layer and the enhancement layer are specified in different video coding standards. Thus, base layer pictures are coded according to a different coding standard or format than enhancement layer pictures. For example, the base layer may be coded with H.264/AVC and an enhancement layer may be coded with an HEVC extension. It should be understood that many of the scalability types may be combined and applied together. For example color gamut scalability and bit-depth scalability may be combined. The term layer may be used in context of any type of scalability, including view scalability and depth enhancements. An enhancement layer may refer to any type of an enhancement, such as SNR, spatial, multiview, depth, bit-depth, chroma format, and/or color gamut enhancement. A base layer may refer to any type of a base video sequence, such as a base view, a base layer for SNR/spatial scalability, or a texture base view for depth-enhanced video coding. Various technologies for providing three-dimensional (3D) video content are currently investigated and developed. It may be considered that in stereoscopic or two-view video, one video sequence or view is presented for the left eye while a parallel view is presented for the right eye. More than two parallel views may be needed for applications which enable viewpoint switching or for autostereoscopic displays which may present a large number of views simultaneously and let the viewers to observe the content from different viewpoints. Intense studies have been focused on video coding for autostereoscopic displays and such multiview applications wherein a viewer is able to see only one pair of stereo video from a specific viewpoint and another pair of stereo video from a different viewpoint. One of the most feasible approaches for such multiview applications has turned out to be such wherein only a limited number of views, e.g. a mono or a stereo video plus some supplementary data, is provided to a decoder side and all required views are then rendered (i.e. synthesized) locally be the decoder to be displayed on a display. A view may be defined as a sequence of pictures representing one camera or viewpoint. The pictures representing a view may also be called view components. In other words, a view component may be defined as a coded representation of a view in a single access unit. In multiview video coding, more than one view is coded in a bitstream. Since views are typically intended to be displayed on stereoscopic or multiview autostrereoscopic display or to be used for other 3D arrangements, they typically represent the same scene and are content-wise partly overlapping although representing different viewpoints to the content. Hence, inter-view prediction may be utilized in multiview video coding to take advantage of inter-view correlation and improve compression efficiency. One way to realize inter-view prediction is to include one or more decoded pictures of one or more other views in the reference picture list(s) of a picture being coded or decoded residing within a first view. View scalability may refer to such multiview video coding or multiview video bitstreams, which enable removal or omission of one or more coded views, while the resulting bitstream remains conforming and represents video with a smaller number of views than originally. Region of Interest (ROI) coding may be defined to refer to coding a particular region within a video at a higher fidelity. There exists several methods for encoders and/or other entities to determine ROIs from input pictures to be encoded. For example, face detection may be used and faces may be determined to be ROIs. Additionally or alternatively, in another example, objects that are in focus may be detected and determined to be ROIs, while objects out of focus are determined to be outside ROIs. Additionally or alternatively, in another example, the distance to objects may be estimated or known, e.g. on the basis of a depth sensor, and ROIs may be determined to be those objects that are relatively close to the camera rather than in the background. ROI scalability may be defined as a type of scalability wherein an enhancement layer enhances only part of a reference-layer picture e.g. spatially, quality-wise, in bit-depth, and/or along other scalability dimensions. As ROI scalability may be used together with other types of scalabilities, it may be considered to form a different categorization of scalability types. There exists several different applications for ROI coding with different requirements, which may be realized by using ROI scalability. For example, an enhancement layer can be transmitted to enhance the quality and/or a resolution of a region in the base layer. A decoder receiving both enhancement and base layer bitstream might decode both layers and overlay the decoded pictures on top of each other and display the final picture. The spatial correspondence between the enhancement layer picture and the reference layer region, or similarly the enhancement layer region and the base layer picture may be indicated by the encoder and/or decoded by the decoder using for example so-called scaled reference layer offsets. Scaled reference layer offsets may be considered to specify the positions of the corner samples of the upsampled reference layer picture relative to the respective corner samples of the enhancement layer picture. The offset values may be signed, which enables the use of the offset values to be used in both types of extended spatial scalability, as illustrated inFIG.19aandFIG.19b. In case of region-of-interest scalability (FIG.19a), the enhancement layer picture110corresponds to a region112of the reference layer picture116and the scaled reference layer offsets indicate the corners of the upsampled reference layer picture that extend the area of the enhance layer picture. Scaled reference layer offsets may be indicated by four syntax elements (e.g. per a pair of an enhancement layer and its reference layer), which may be referred to as scaled_ref_layer_top_offset118, scaled_ref_layer_bottom_offset120, scaled_ref_layer_right_offset122and scaled_ref_layer_left_offset124. The reference layer region that is upsampled may be concluded by the encoder and/or the decoder by downscaling the scaled reference layer offsets according to the ratio between the enhancement layer picture height or width and the upsampled reference layer picture height or width, respectively. The downscaled scaled reference layer offset may be then be used to obtain the reference layer region that is upsampled and/or to determine which samples of the reference layer picture collocate to certain samples of the enhancement layer picture. In case the reference layer picture corresponds to a region of the enhancement layer picture (FIG.19b), the scaled reference layer offsets indicate the corners of the upsampled reference layer picture that are within the area of the enhance layer picture. The scaled reference layer offset may be used to determine which samples of the upsampled reference layer picture collocate to certain samples of the enhancement layer picture. It is also possible to mix the types of extended spatial scalability, i.e apply one type horizontally and another type vertically. Scaled reference layer offsets may be indicated by the encoder in and/or decoded by the decoder from for example a sequence-level syntax structure, such as SPS and/or VPS. The accuracy of scaled reference offsets may be pre-defined for example in a coding standard and/or specified by the encoder and/or decoded by the decoder from the bitstream. For example, an accuracy of 1/16th of the luma sample size in the enhancement layer may be used. Scaled reference layer offsets may be indicated, decoded, and/or used in the encoding, decoding and/or displaying process when no inter-layer prediction takes place between two layers. Some coding standards allow creation of scalable bit streams. A meaningful decoded representation can be produced by decoding only certain parts of a scalable bit stream. Scalable bit streams can be used for example for rate adaptation of pre-encoded unicast streams in a streaming server and for transmission of a single bit stream to terminals having different capabilities and/or with different network conditions. A list of some other use cases for scalable video coding can be found in the ISO/IEC JTC1 SC29 WG11 (MPEG) output document N5540, “Applications and Requirements for Scalable Video Coding”, the 64thMPEG meeting, Mar. 10 to 14, 2003, Pattaya, Thailand. A coding standard may include a sub-bitstream extraction process, and such is specified for example in SVC, MVC, and HEVC. The sub-bitstream extraction process relates to converting a bitstream, typically by removing NAL units, to a sub-bitstream. which may also be referred to as a bitstream subset. The sub-bitstream still remains conforming to the standard. For example, in HEVC, the bitstream created by excluding all VCL NAL units having a TemporalId value greater than a selected value and including all other VCL NAL units remains conforming. In HEVC, the sub-bitstream extraction process takes a TemporalId and/or a list of nuh_layer_id values as input and derives a sub-bitstream (also known as a bitstream subset) by removing from the bitstream all NAL units with TemporalId greater than the input TemporalId value or nuh_layer_id value not among the values in the input list of nuh_layer_id values. A coding standard or system may refer to a term operation point or alike, which may indicate the scalable layers and/or sub-layers under which the decoding operates and/or may be associated with a sub-bitstream that includes the scalable layers and/or sub-layers being decoded. Some non-limiting definitions of an operation point are provided in the following. In HEVC, an operation point is defined as bitstream created from another bitstream by operation of the sub-bitstream extraction process with the another bitstream, a target highest TemporalId, and a target layer identifier list as inputs. The VPS of HEVC specifies layer sets and HRD parameters for these layer sets. A layer set may be used as the target layer identifier list in the sub-bitstream extraction process. In SHVC and MV-HEVC, an operation point definition may include a consideration a target output layer set. In SHVC and MV-HEVC, an operation point may be defined as A bitstream that is created from another bitstream by operation of the sub-bitstream extraction process with the another bitstream, a target highest TemporalId, and a target layer identifier list as inputs, and that is associated with a set of target output layers. An output layer set may be defined as a set of layers consisting of the layers of one of the specified layer sets, where one or more layers in the set of layers are indicated to be output layers. An output layer may be defined as a layer of an output layer set that is output when the decoder and/or the HRD operates using the output layer set as the target output layer set. In MV-HEVC/SHVC, the variable TargetOptLayerSetIdx may specify which output layer set is the target output layer set by setting TargetOptLayerSetIdx equal to the index of the output layer set that is the target output layer set. TargetOptLayerSetIdx may be set for example by the HRD and/or may be set by external means, for example by a player or alike through an interface provided by the decoder. In MV-HEVC/SHVC, a target output layer may be defined as a layer that is to be output and is one of the output layers of the output layer set with index olsIdx such that TargetOptLayerSetIdx is equal to olsIdx. MV-HEVC/SHVC enable derivation of a “default” output layer set for each layer set specified in the VPS using a specific mechanism or by indicating the output layers explicitly. Two specific mechanisms have been specified: it may be specified in the VPS that each layer is an output layer or that only the highest layer is an output layer in a “default” output layer set. Auxiliary picture layers may be excluded from consideration when determining whether a layer is an output layer using the mentioned specific mechanisms. In addition, to the “default” output layer sets, the VPS extension enables to specify additional output layer sets with selected layers indicated to be output layers. In MV-HEVC/SHVC, a profile_tier_level( ) syntax structure is associated for each output layer set. To be more exact, a list of profile_tier_level( ) syntax structures is provided in the VPS extension. and an index to the applicable profile_tier_level( ) within the list is given for each output layer set. In other words, a combination of profile, tier, and level values is indicated for each output layer set. While a constant set of output layers suits well use cases and bitstreams where the highest layer stays unchanged in each access unit, they may not support use cases where the highest layer changes from one access unit to another. It has therefore been proposed that encoders can specify the use of alternative output layers within the bitstream and in response to the specified use of alternative output layers decoders output a decoded picture from an alternative output layer in the absence of a picture in an output layer within the same access unit. Several possibilities exist how to indicate alternative output layers. For example, each output layer in an output layer set may be associated with a minimum alternative output layer, and output-layer-wise syntax element(s) may be used for specifying alternative output layer(s) for each output layer. Alternatively, the alternative output layer set mechanism may be constrained to be used only for output layer sets containing only one output layer, and output-layer-set-wise syntax element(s) may be used for specifying alternative output layer(s) for the output layer of the output layer set. Alternatively, the alternative output layer set mechanism may be constrained to be used only for bitstreams or CVSs in which all specified output layer sets contain only one output layer, and the alternative output layer(s) may be indicated by bitstream- or CVS-wise syntax element(s). The alternative output layer(s) may be for example specified by listing e.g. within VPS the alternative output layers (e.g. using their layer identifiers or indexes of the list of direct or indirect reference layers), indicating a minimum alternative output layer (e.g. using its layer identifier or its index within the list of direct or indirect reference layers), or a flag specifying that any direct or indirect reference layer is an alternative output layer. When more than one alternative output layer is enabled to be used, it may be specified that the first direct or indirect inter-layer reference picture present in the access unit in descending layer identifier order down to the indicated minimum alternative output layer is output. In MVC, an operation point may be defined as follows: An operation point is identified by a temporal_id value representing the target temporal level and a set of view_id values representing the target output views. One operation point is associated with a bitstream subset, which consists of the target output views and all other views the target output views depend on, that is derived using the sub-bitstream extraction process with tIdTarget equal to the temporal_id value and viewIdTargetList consisting of the set of view_id values as inputs. More than one operation point may be associated with the same bitstream subset. When “an operation point is decoded”, a bitstream subset corresponding to the operation point may be decoded and subsequently the target output views may be output. As indicated earlier, MVC is an extension of H.264/AVC. Many of the definitions, concepts, syntax structures, semantics, and decoding processes of H.264/AVC apply also to MVC as such or with certain generalizations or constraints. Some definitions, concepts, syntax structures, semantics, and decoding processes of MVC are described in the following. An access unit in MVC is defined to be a set of NAL units that are consecutive in decoding order and contain exactly one primary coded picture consisting of one or more view components. In addition to the primary coded picture, an access unit may also contain one or more redundant coded pictures, one auxiliary coded picture, or other NAL units not containing slices or slice data partitions of a coded picture. The decoding of an access unit results in one decoded picture consisting of one or more decoded view components, when decoding errors, bitstream errors or other errors which may affect the decoding do not occur. In other words, an access unit in MVC contains the view components of the views for one output time instance. A view component may be referred to as a coded representation of a view in a single access unit. Inter-view prediction may be used in MVC and may refer to prediction of a view component from decoded samples of different view components of the same access unit. In MVC, inter-view prediction is realized similarly to inter prediction. For example, inter-view reference pictures are placed in the same reference picture list(s) as reference pictures for inter prediction, and a reference index as well as a motion vector are coded or inferred similarly for inter-view and inter reference pictures. An anchor picture is a coded picture in which all slices may reference only slices within the same access unit. i.e., inter-view prediction may be used, but no inter prediction is used, and all following coded pictures in output order do not use inter prediction from any picture prior to the coded picture in decoding order. Inter-view prediction may be used for IDR view components that are part of a non-base view. A base view in MVC is a view that has the minimum value of view order index in a coded video sequence. The base view can be decoded independently of other views and does not use inter-view prediction. The base view can be decoded by H.264/AVC decoders supporting only the single-view profiles, such as the Baseline Profile or the High Profile of H.264/AVC. In the MVC standard, many of the sub-processes of the MVC decoding process use the respective sub-processes of the H.264/AVC standard by replacing term “picture”, “frame”, and “field” in the sub-process specification of the H.264/AVC standard by “view component”, “frame view component”, and “field view component”, respectively. Likewise, terms “picture”, “frame”, and “field” are often used in the following to mean “view component”, “frame view component”, and “field view component”, respectively. In the context of multiview video coding, view order index may be defined as an index that indicates the decoding or bitstream order of view components in an access unit. In MVC, the inter-view dependency relationships are indicated in a sequence parameter set MVC extension, which is included in a sequence parameter set. According to the MVC standard, all sequence parameter set MVC extensions that are referred to by a coded video sequence are required to be identical. A texture view refers to a view that represents ordinary video content, for example has been captured using an ordinary camera, and is usually suitable for rendering on a display. A texture view typically comprises pictures having three components, one luma component and two chroma components. In the following, a texture picture typically comprises all its component pictures or color components unless otherwise indicated for example with terms luma texture picture and chroma texture picture. A depth view refers to a view that represents distance information of a texture sample from the camera sensor, disparity or parallax information between a texture sample and a respective texture sample in another view, or similar information. A depth view may comprise depth pictures (a.k.a. depth maps) having one component, similar to the luma component of texture views. A depth map is an image with per-pixel depth information or similar. For example, each sample in a depth map represents the distance of the respective texture sample or samples from the plane on which the camera lies. In other words, if the z axis is along the shooting axis of the cameras (and hence orthogonal to the plane on which the cameras lie), a sample in a depth map represents the value on the z axis. The semantics of depth map values may for example include the following:1. Each luma sample value in a coded depth view component represents an inverse of real-world distance (Z) value, i.e. 1/Z. normalized in the dynamic range of the luma samples, such as to the range of 0 to 255, inclusive, for 8-bit luma representation. The normalization may be done in a manner where the quantization 1/Z is uniform in terms of disparity.2. Each luma sample value in a coded depth view component represents an inverse of real-world distance (Z) value, i.e. 1/Z, which is mapped to the dynamic range of the luma samples, such as to the range of 0 to 255, inclusive, for 8-bit luma representation, using a mapping function f(1/Z) or table, such as a piece-wise linear mapping. In other words, depth map values result in applying the function f(1/Z).3. Each luma sample value in a coded depth view component represents a real-world distance (Z) value normalized in the dynamic range of the luma samples, such as to the range of 0 to 255, inclusive, for 8-bit luma representation.4. Each luma sample value in a coded depth view component represents a disparity or parallax value from the present depth view to another indicated or derived depth view or view position. The semantics of depth map values may be indicated in the bitstream for example within a video parameter set syntax structure, a sequence parameter set syntax structure, a video usability information syntax structure, a picture parameter set syntax structure, a camera/depth/adaptation parameter set syntax structure, a supplemental enhancement information message, or anything alike. Depth-enhanced video refers to texture video having one or more views associated with depth video having one or more depth views. A number of approaches may be used for representing of depth-enhanced video, including the use of video plus depth (V+D), multiview video plus depth (MVD), and layered depth video (LDV). In the video plus depth (V+D) representation, a single view of texture and the respective view of depth are represented as sequences of texture picture and depth pictures, respectively. The MVD representation contains a number of texture views and respective depth views. In the LDV representation, the texture and depth of the central view are represented conventionally, while the texture and depth of the other views are partially represented and cover only the dis-occluded areas required for correct view synthesis of intermediate views. A texture view component may be defined as a coded representation of the texture of a view in a single access unit. A texture view component in depth-enhanced video bitstream may be coded in a manner that is compatible with a single-view texture bitstream or a multi-view texture bitstream so that a single-view or multi-view decoder can decode the texture views even if it has no capability to decode depth views. For example, an H.264/AVC decoder may decode a single texture view from a depth-enhanced H.264/AVC bitstream. A texture view component may alternatively be coded in a manner that a decoder capable of single-view or multi-view texture decoding, such H.264/AVC or MVC decoder, is not able to decode the texture view component for example because it uses depth-based coding tools. A depth view component may be defined as a coded representation of the depth of a view in a single access unit. A view component pair may be defined as a texture view component and a depth view component of the same view within the same access unit. Depth-enhanced video may be coded in a manner where texture and depth are coded independently of each other. For example, texture views may be coded as one MVC bitstream and depth views may be coded as another MVC bitstream. Depth-enhanced video may also be coded in a manner where texture and depth are jointly coded. In a form of a joint coding of texture and depth views, some decoded samples of a texture picture or data elements for decoding of a texture picture are predicted or derived from some decoded samples of a depth picture or data elements obtained in the decoding process of a depth picture. Alternatively or in addition, some decoded samples of a depth picture or data elements for decoding of a depth picture are predicted or derived from some decoded samples of a texture picture or data elements obtained in the decoding process of a texture picture. In another option, coded video data of texture and coded video data of depth are not predicted from each other or one is not coded/decoded on the basis of the other one, but coded texture and depth view may be multiplexed into the same bitstream in the encoding and demultiplexed from the bitstream in the decoding. In yet another option, while coded video data of texture is not predicted from coded video data of depth in e.g. below slice layer, some of the high-level coding structures of texture views and depth views may be shared or predicted from each other. For example, a slice header of coded depth slice may be predicted from a slice header of a coded texture slice. Moreover, some of the parameter sets may be used by both coded texture views and coded depth views. Scalability may be enabled in two basic ways. Either by introducing new coding modes for performing prediction of pixel values or syntax from lower layers of the scalable representation or by placing the lower layer pictures to a reference picture buffer (e.g. a decoded picture buffer, DPB) of the higher layer. The first approach may be more flexible and thus may provide better coding efficiency in most cases. However, the second, reference frame based scalability, approach may be implemented efficiently with minimal changes to single layer codecs while still achieving majority of the coding efficiency gains available. Essentially a reference frame based scalability codec may be implemented by utilizing the same hardware or software implementation for all the layers, just taking care of the DPB management by external means. A scalable video encoder for quality scalability (also known as Signal-to-Noise or SNR) and/or spatial scalability may be implemented as follows. For a base layer, a conventional non-scalable video encoder and decoder may be used. The reconstructed/decoded pictures of the base layer are included in the reference picture buffer and/or reference picture lists for an enhancement layer. In case of spatial scalability, the reconstructed/decoded base-layer picture may be upsampled prior to its insertion into the reference picture lists for an enhancement-layer picture. The base layer decoded pictures may be inserted into a reference picture list(s) for coding/decoding of an enhancement layer picture similarly to the decoded reference pictures of the enhancement layer. Consequently, the encoder may choose a base-layer reference picture as an inter prediction reference and indicate its use with a reference picture index in the coded bitstream. The decoder decodes from the bitstream, for example from a reference picture index, that a base-layer picture is used as an inter prediction reference for the enhancement layer. When a decoded base-layer picture is used as the prediction reference for an enhancement layer, it is referred to as an inter-layer reference picture. While the previous paragraph described a scalable video codec with two scalability layers with an enhancement layer and a base layer, it needs to be understood that the description can be generalized to any two layers in a scalability hierarchy with more than two layers. In this case, a second enhancement layer may depend on a first enhancement layer in encoding and/or decoding processes, and the first enhancement layer may therefore be regarded as the base layer for the encoding and/or decoding of the second enhancement layer. Furthermore, it needs to be understood that there may be inter-layer reference pictures from more than one layer in a reference picture buffer or reference picture lists of an enhancement layer, and each of these inter-layer reference pictures may be considered to reside in a base layer or a reference layer for the enhancement layer being encoded and/or decoded. A scalable video coding and/or decoding scheme may use multi-loop coding and/or decoding, which may be characterized as follows. In the encoding/decoding, a base layer picture may be reconstructed/decoded to be used as a motion-compensation reference picture for subsequent pictures, in coding/decoding order, within the same layer or as a reference for inter-layer (or inter-view or inter-component) prediction. The reconstructed/decoded base layer picture may be stored in the DPB. An enhancement layer picture may likewise be reconstructed/decoded to be used as a motion-compensation reference picture for subsequent pictures, in coding/decoding order, within the same layer or as reference for inter-layer (or inter-view or inter-component) prediction for higher enhancement layers, if any. In addition to reconstructed/decoded sample values, syntax element values of the base/reference layer or variables derived from the syntax element values of the base/reference layer may be used in the inter-layer/inter-component/inter-view prediction. In some cases, data in an enhancement layer can be truncated after a certain location, or even at arbitrary positions, where each truncation position may include additional data representing increasingly enhanced visual quality. Such scalability is referred to as fine-grained (granularity) scalability (FGS). SVC uses an inter-layer prediction mechanism, wherein certain information can be predicted from layers other than the currently reconstructed layer or the next lower layer. Information that could be inter-layer predicted includes intra texture, motion and residual data. Inter-layer motion prediction includes the prediction of block coding mode, header information, block partitioning, etc., wherein motion from the lower layer may be used for prediction of the higher layer. In case of intra coding, a prediction from surrounding macroblocks or from co-located macroblocks of lower layers is possible. These prediction techniques do not employ information from earlier coded access units and hence, are referred to as intra prediction techniques. Furthermore, residual data from lower layers can also be employed for prediction of the current layer. Scalable video (de)coding may be realized with a concept known as single-loop decoding, where decoded reference pictures are reconstructed only for the highest layer being decoded while pictures at lower layers may not be fully decoded or may be discarded after using them for inter-layer prediction. In single-loop decoding, the decoder performs motion compensation and full picture reconstruction only for the scalable layer desired for playback (called the “desired layer” or the “target layer”), thereby reducing decoding complexity when compared to multi-loop decoding. All of the layers other than the desired layer do not need to be fully decoded because all or part of the coded picture data is not needed for reconstruction of the desired layer. However, lower layers (than the target layer) may be used for inter-layer syntax or parameter prediction, such as interlayer motion prediction. Additionally or alternatively, lower layers may be used for inter-layer intra prediction and hence intra-coded blocks of lower layers may have to be decoded. Additionally or alternatively, inter-layer residual prediction may be applied. where the residual information of the lower layers may be used for decoding of the target layer and the residual information may need to be decoded or reconstructed. In some coding arrangements, a single decoding loop is needed for decoding of most pictures, while a second decoding loop may be selectively applied to reconstruct so-called base representations (i.e. decoded base layer pictures), which may be needed as prediction references but not for output or display. SVC as allows the use of single-loop decoding. It is enabled by using a constrained intra texture prediction mode, whereby the inter-layer intra texture prediction can be applied to macroblocks (MBs) for which the corresponding block of the base layer is located inside intra-MBs. At the same time, those intra-MBs in the base layer use constrained intra-prediction (e.g., having the syntax element “constrained_intra_pred_flag” equal to 1). In single-loop decoding, the decoder performs motion compensation and full picture reconstruction only for the scalable layer desired for playback (called the “desired layer” or the “target layer”), thereby greatly reducing decoding complexity. All of the layers other than the desired layer do not need to be fully decoded because all or part of the data of the MBs not used for inter-layer prediction (be it inter-layer intra texture prediction, inter-layer motion prediction or inter-layer residual prediction) is not needed for reconstruction of the desired layer. A single decoding loop is needed for decoding of most pictures, while a second decoding loop is selectively applied to reconstruct the base representations, which are needed as prediction references but not for output or display, and are reconstructed only for the so called key pictures (for which “store_ref_base_pic_flag” is equal to 1). FGS was included in some draft versions of the SVC standard, but it was eventually excluded from the final SVC standard. FGS is subsequently discussed in the context of some draft versions of the SVC standard. The scalability provided by those enhancement layers that cannot be truncated is referred to as coarse-grained (granularity) scalability (CGS). It collectively includes the traditional quality (SNR) scalability and spatial scalability. The SVC standard supports the so-called medium-grained scalability (MGS), where quality enhancement pictures are coded similarly to SNR scalable layer pictures but indicated by high-level syntax elements similarly to FGS layer pictures, by having the quality_id syntax element greater than 0. The scalability structure in SVC may be characterized by three syntax elements: “temporal_id,” “dependency_id” and “quality_id.” The syntax element “temporal_id” is used to indicate the temporal scalability hierarchy or, indirectly, the frame rate. A scalable layer representation comprising pictures of a smaller maximum “temporal_id” value has a smaller frame rate than a scalable layer representation comprising pictures of a greater maximum “temporal_id”. A given temporal layer typically depends on the lower temporal layers (i.e., the temporal layers with smaller “temporal_id” values) but does not depend on any higher temporal layer. The syntax element “dependency_id” is used to indicate the CGS inter-layer coding dependency hierarchy (which, as mentioned earlier, includes both SNR and spatial scalability). At any temporal level location, a picture of a smaller “dependency_id” value may be used for inter-layer prediction for coding of a picture with a greater “dependency_id” value. The syntax element “quality_id” is used to indicate the quality level hierarchy of a FGS or MGS layer. At any temporal location, and with an identical “dependency_id” value, a picture with “quality_id” equal to QL uses the picture with “quality_id” equal to QL-1 for inter-layer prediction. A coded slice with “quality_id” larger than 0 may be coded as either a truncatable FGS slice or a non-truncatable MGS slice. For simplicity, all the data units (e.g., Network Abstraction Layer units or NAL units in the SVC context) in one access unit having identical value of “dependency_id” are referred to as a dependency unit or a dependency representation. Within one dependency unit, all the data units having identical value of “quality_id” are referred to as a quality unit or layer representation. A base representation, also known as a decoded base picture, is a decoded picture resulting from decoding the Video Coding Layer (VCL) NAL units of a dependency unit having “quality_id” equal to 0 and for which the “store_ref_base_pic_flag” is set equal to 1. An enhancement representation, also referred to as a decoded picture, results from the regular decoding process in which all the layer representations that are present for the highest dependency representation are decoded. As mentioned earlier, CGS includes both spatial scalability and SNR scalability. Spatial scalability is initially designed to support representations of video with different resolutions. For each time instance, VCL NAL units are coded in the same access unit and these VCL NAL units can correspond to different resolutions. During the decoding, a low resolution VCL NAL unit provides the motion field and residual which can be optionally inherited by the final decoding and reconstruction of the high resolution picture. When compared to older video compression standards, SVC's spatial scalability has been generalized to enable the base layer to be a cropped and zoomed version of the enhancement layer. MGS quality layers are indicated with “quality_id” similarly as FGS quality layers. For each dependency unit (with the same “dependency_id”), there is a layer with “quality_id” equal to 0 and there can be other layers with “quality_id” greater than 0. These layers with “quality_id” greater than 0 are either MGS layers or FGS layers, depending on whether the slices are coded as truncatable slices. In the basic form of FGS enhancement layers, only inter-layer prediction is used. Therefore, FGS enhancement layers can be truncated freely without causing any error propagation in the decoded sequence. However. the basic form of FGS suffers from low compression efficiency. This issue arises because only low-quality pictures are used for inter prediction references. It has therefore been proposed that FGS-enhanced pictures be used as inter prediction references. However, this may cause encoding-decoding mismatch, also referred to as drift, when some FGS data are discarded. One feature of a draft SVC standard is that the FGS NAL units can be freely dropped or truncated, and a feature of the SVC standard is that MGS NAL units can be freely dropped (but cannot be truncated) without affecting the conformance of the bitstream. As discussed above, when those FGS or MGS data have been used for inter prediction reference during encoding, dropping or truncation of the data would result in a mismatch between the decoded pictures in the decoder side and in the encoder side. This mismatch is also referred to as drift. To control drift due to the dropping or truncation of FGS or MGS data, SVC applied the following solution: In a certain dependency unit, a base representation (by decoding only the CGS picture with “quality_id” equal to 0 and all the dependent-on lower layer data) is stored in the decoded picture buffer. When encoding a subsequent dependency unit with the same value of “dependency_id,” all of the NAL units, including FGS or MGS NAL units, use the base representation for inter prediction reference. Consequently, all drift due to dropping or truncation of FGS or MGS NAL units in an earlier access unit is stopped at this access unit. For other dependency units with the same value of “dependency_id,” all of the NAL units use the decoded pictures for inter prediction reference, for high coding efficiency. Each NAL unit includes in the NAL unit header a syntax element “use_ref_base_pic_flag.” When the value of this element is equal to 1, decoding of the NAL unit uses the base representations of the reference pictures during the inter prediction process. The syntax element “store_ref_base_pic_flag” specifies whether (when equal to 1) or not (when equal to 0) to store the base representation of the current picture for future pictures to use for inter prediction. NAL units with “quality_id” greater than 0 do not contain syntax elements related to reference picture lists construction and weighted prediction, i.e., the syntax elements “num_ref_active_1x_minus1” (x=0 or 1), the reference picture list reordering syntax table, and the weighted prediction syntax table are not present. Consequently, the MGS or FGS layers have to inherit these syntax elements from the NAL units with “quality_id” equal to 0 of the same dependency unit when needed. In SVC, a reference picture list consists of either only base representations (when “use_ref_base_pic_flag” is equal to 1) or only decoded pictures not marked as “base reprosentation” (when “use_ref_base_pic_flag” is equal to 0), but never both at the same time. Another categorization of scalable coding is based on whether the same or different coding standard or technology is used as the basis for the base layer and enhancement layers. Terms hybrid codec scalability or standards scalability may be used to indicate a scenario where one coding standard or system is used for some layers, while another coding standard or system is used for some other layers. For example, the base layer may be AVC-coded, while one or more enhancement layers may be coded with an HEVC extension, such as SHVC or MV-HEVC. Work is ongoing to specify scalable and multiview extensions to the HEVC standard. The multiview extension of HEVC, referred to as MV-HEVC, is similar to the MVC extension of H.264/AVC. Similarly to MVC, in MV-HEVC, inter-view reference pictures can be included in the reference picture list(s) of the current picture being coded or decoded. The scalable extension of HEVC, referred to as SHVC, is planned to be specified so that it uses multi-loop decoding operation (unlike the SVC extension of H.264/AVC). SHVC is reference index based, i.e. an inter-layer reference picture can be included in a one or more reference picture lists of the current picture being coded or decoded (as described above). It is possible to use many of the same syntax structures, semantics, and decoding processes for MV-HEVC and SHVC. Other types of scalability, such as depth-enhanced video, may also be realized with the same or similar syntax structures, semantics, and decoding processes as in MV-HEVC and SHVC. For the enhancement layer coding, the same concepts and coding tools of HEVC may be used in SHVC, MV-HEVC, and/or alike. However, the additional inter-layer prediction tools, which employ already coded data (including reconstructed picture samples and motion parameters a.k.a motion information) in reference layer for efficiently coding an enhancement layer, may be integrated to SHVC, MV-HEVC, and/or alike codec. In MV-HEVC, SHVC and/or alike, VPS may for example include a mapping of the LayerId value derived from the NAL unit header to one or more scalability dimension values, for example correspond to dependency_id, quality_id, view_id, and depth_flag for the layer defined similarly to SVC and MVC. In MV-HEVC/SHVC, it may be indicated in the VPS that a layer with layer identifier value greater than 0 has no direct reference layers, i.e. that the layer is not inter-layer predicted from any other layer. In other words, an MV-HEVC/SHVC bitstream may contain layers that are independent of each other, which may be referred to as simulcast layers. A part of VPS, which specifies the scalability dimensions that may be present in the bitstream, the mapping of nuh_layer_id values to scalability dimension values, and the dependencies between layers may be specified with the following syntax: Descriptorvps_extension( ) {splitting_flagu(1)for( i = 0, NumScalabilityTypes = 0; i < 16; i++ ) {scalability_mask_flag[ i ]u(1)NumScalabilityTypes += scalability_mask_flag[ i ]}for( j = 0; j < ( NumScalabilityTypes − splitting flag );j++ )dimension_id_len_minus1[ j ]u(3)vps_nuh_layer_id_present_flagu(1)for( i = 1; i <= MaxLayersMinus1; i++ ) {if( vps_nuh_layer_id_present_flag )layer_id_in_nuh[ i ]u(6)if( !splitting_flag )for( j = 0; j < NumScalabilityTypes; j++ )dimension_id[ i ][ j ]u(v)}view_id_lenu(4)if( view_id_len > 0 )for( i = 0; i < NumViews; i++ )view_id_val[ i ]u(v)for( i = 1; i <= MaxLayersMinus1; i++ )for( j = 0; j < i; j++ )direct_dependency_flag[ i ][ j ]u(1)... The semantics of the above-shown part of the VPS may be specified as described in the following paragraphs. splitting_flag equal to 1 indicates that the dimension_id [i][j] syntax elements are not present and that the binary representation of the nuh_layer_id value in the NAL unit header are split into NumScalabilityTypes segments with lengths, in bits, according to the values of dimension_id_len_minus1[j] and that the values of dimension_id[LayerIdxInVps[nuh_layer_id]][j] are inferred from the NumScalabilityTypes segments. splitting_flag equal to 0 indicates that the syntax elements dimension_id[i][j] are present. In the following example semantics, without loss of generality, it is assumed that splitting_flag is equal to 0. scalability_mask_flag[i] equal to 1 indicates that dimension_id syntax elements corresponding to the i-th scalability dimension in the following table are present. scalability_mask_flag[i] equal to 0 indicates that dimension_id syntax elements corresponding to the i-th scalability dimension are not present. scalability maskScalabilityIdindexScalability dimensionmapping0Reserved1MultiviewView Order Index2Spatial/qualityscalabilityDependencyId3AuxiliaryAuxId4-15Reserved In future 3D extensions of HEVC, scalability mask index 0 may be used to indicate depth maps. dimension_id_len_minus1[j] plus 1 specifies the length, in bits, of the dimension_id[i][j] syntax element. vps_nuh_layer_id_present_flag equal to 1 specifies that layer_id_in_nuh[i] for i from 0 to MaxLayersMinus1 (which is equal to the maximum number of layers specified in the VPS minus 1), inclusive, are present. vps_nuh_layer_id_present_flag equal to 0 specifies that layer_id_in_nuh[i] for i from 0 to MaxLayersMinus1, inclusive, are not present. layer_id_in_nuh[i] specifies the value of the nuh_layer_id syntax element in VCL NAL units of the i-th layer. For i in the range of 0 to MaxLayersMinus1, inclusive, when layer_id_in_nuh[i] is not present, the value is inferred to be equal to i. When i is greater than 0, layer_id_in_nuh[i] is greater than layer_id_in_nuh[i−1]. For i from 0 to MaxLayersMinus1, inclusive, the variable LayerIdxInVps[layer_id_in_nuh[i]] is set equal to i. dimension_id[i][j] specifies the identifier of the j-th present scalability dimension type of the i-th layer. The number of bits used for the representation of dimension_id[i][j] is dimension_id_len_minus1[j]+1 bits. When splitting_flag is equal to 0, for j from 0 to NumScalabilityTypes−1, inclusive, dimension_id[0][j] is inferred to be equal to 0 The variable ScalabilityId[i][smIdx] specifying the identifier of the smIdx-th scalability dimension type of the i-th layer, the variable ViewOrderIdx[layer_id_in_nuh[i]] specifying the view order index of the i-th layer, DependencyId[layer_id_in_nuh[i]] specifying the spatial/quality scalability identifier of the i-th layer, and the variable ViewScalExtLayerFlag[layer_id_in_nuh[i]] specifying whether the i-th layer is a view scalability extension layer are derived as follows: NumViews = 1for( i = 0; i <= MaxLayersMinus1; i++ ) {lId = layer_id_in_nuh[ i ]for( smIdx= 0, j = 0; smIdx < 16; smIdx++ )if( scalability_mask_flag[ smIdx ] )ScalabilityId[ i ][ smIdx ] = dimension_id[ i ][ j++ ]ViewOrderIdx[ lId ] = ScalabilityId[ i ][ 1 ]DependencyId[ lId ] = ScalabilityId[ i ][ 2 ]if( i > 0 && ( ViewOrderIdx[ lId ] != ScalabilityId[ i − 1][ 1 ] ) )NumViews++ViewScalExtLayerFlag[ lId ] = ( ViewOrderIdx[ lId ] > 0 )AuxId[ lId ] = ScalabilityId[ i ][ 3 ]} Enhancement layers or layers with a layer identifier value greater than 0 may be indicated to contain auxiliary video complementing the base layer or other layers. For example, in the present draft of MV-HEVC, auxiliary pictures may be encoded in a bitstream using auxiliary picture layers. An auxiliary picture layer is associated with its own scalability dimension value, AuxId (similarly to e.g. view order index). Layers with AuxId greater than 0 contain auxiliary pictures. A layer carries only one type of auxiliary pictures, and the type of auxiliary pictures included in a layer may be indicated by its AuxId value. In other words, AuxId values may be mapped to types of auxiliary pictures. For example, AuxId equal to 1 may indicate alpha planes and AuxId equal to 2 may indicate depth pictures. An auxiliary picture may be defined as a picture that has no normative effect on the decoding process of primary pictures. In other words, primary pictures (with AuxId equal to 0) may be constrained not to predict from auxiliary pictures. An auxiliary picture may predict from a primary picture, although there may be constraints disallowing such prediction, for example based on the AuxId value. SEI messages may be used to convey more detailed characteristics of auxiliary picture layers, such as the depth range represented by a depth auxiliary layer. The present draft of MV-HEVC includes support of depth auxiliary layers. Different types of auxiliary pictures may be used including but not limited to the following: Depth pictures; Alpha pictures; Overlay pictures; and Label pictures. In Depth pictures a sample value represents disparity between the viewpoint (or camera position) of the depth picture or depth or distance. In Alpha pictures (a.k.a. alpha planes and alpha matte pictures) a sample value represents transparency or opacity. Alpha pictures may indicate for each pixel a degree of transparency or equivalently a degree of opacity. Alpha pictures may be monochrome pictures or the chroma components of alpha pictures may be set to indicate no chromaticity (e.g. 0 when chroma samples values are considered to be signed or 128 when chroma samples values are 8-bit and considered to be unsigned). Overlay pictures may be overlaid on top of the primary pictures in displaying. Overlay pictures may contain several regions and background, where all or a subset of regions may be overlaid in displaying and the background is not overlaid. Label pictures contain different labels for different overlay regions, which can be used to identify single overlay regions. Continuing how the semantics of the presented VPS excerpt may be specified: view_id_len specifies the length, in bits, of the view_id_val[i] syntax element. view_id_val[i] specifies the view identifier of the i-th view specified by the VPS. The length of the view_id_val[i] syntax element is view_id_len bits. When not present, the value of view _id_val[i] is inferred to be equal to 0. For each layer with nuh_layer_id equal to nuhLayerId, the value ViewId[nuhLayerId] is set equal to view_id_val[ViewOrderIdx[nuhLayerId]]. direct_dependency_flag[i][j] equal to 0 specifies that the layer with index j is not a direct reference layer for the layer with index i. direct_dependency_flag[i][j] equal to 1 specifies that the layer with index j may be a direct reference layer for the layer with index i. When direct_dependency_flag[i][j] is not present for i and j in the range of 0 to MaxLayersMinus1, it is inferred to be equal to 0. The variable NumDirectRefLayers[iNuhLId] may be defined as the number of direct reference layers for the layer with nuh_layer_id equal to iNuhLId based on the layer dependency information. The variable RefLayerId[iNuhLId][j] may be defined as the list of nuh_layer_id values of the direct reference layers of the layer with nuh_layer_id equal to iNuhLId, where j is in the range of 0 to NumDirectRefLayers[iNuhLId]−1, inclusive, and each item j in the list corresponds to one direct reference layer. The variables NumDirectRefLayers[iNuhLId] and RefLayerId[iNuhLId][j] may be specified as follows, where MaxLayersMinus1 is equal to the maximum number of layers specified in the VPS minus 1: for( i = 0; i <= MaxLayersMinus1; i++ ) {iNuhLId = layer_id_in_nuh[ i ]NumDirectRefLayers[ iNuhLId ] = 0for( j = 0; j < i; j++ )if( direct_dependency_flag[ i ][ j ] )RefLayerId[ iNuhLId ][ NumDirectRefLayers[ iNuhLId ]++ ] = layer_id_in_nuh[ j ]} VPS may also include information on temporal sub-layers, TemporalId-based constraints on inter-layer prediction, and other constraints on inter-layer prediction, for example using the following syntax: ...vps_sub_layers_max_minus1_present_flagu(1)if( vps_sub_layers_max_minus1_present_flag )for( i = 0; i <= MaxLayersMinus1; i++ )sub_layers_vps_max_minus1[ i ]u(3)max_tid_ref_present_flagu(1)if( max_tid_ref_present_flag )for( i = 0; i < MaxLayersMinus1; i++ )for( j = i + 1; j <= MaxLayersMinus1; j++ )if( direct_dependency_flag[ j ] [ i ] )max_tid_il_ref_pics_plus1[ i ][ j ]u(3)all_ref_layers_active_flagu(1)...max_one_active_ref_layer_flagu(1)... The semantics of the above excerpt of the VPS syntax may be specified as described in the following paragraphs. vps_sub_layers_max_minus1_present_flag equal to 1 specifies that the syntax elements sub_layers_vps_max_minus1[i] are present. vps_sub_layers_max_minus1_present_flag equal to 0 specifies that the syntax elements sub_layers_vps_max_minus1[i] are not present. sub_layers_vps_max_minus1 [i] plus 1 specifies the maximum number of temporal sub-layers that may be present in the CVS for the layer with nuh_layer_id equal to layer_id_in_nuh[i]. When not present, sub_layers_vps_max_minus1[i] is inferred to be equal to vps_max_sub_layers_minus1 (which is present earlier in the VPS syntax). max_tid_ref_present_flag equal to 1 specifies that the syntax element max_tid_il_ref_pics_plus1[i][j] is present. max_tid_ref_present_flag equal to 0 specifies that the syntax element max_tid_il_ref_pics_plus1[i][j] is not present. max_tid_il_ref_pics_plus1[i][j] equal to 0 specifies that within the CVS non-IRAP pictures with nuh_layer_id equal to layer_id_in_nuh[i] are not used as reference for interlayer prediction for pictures with nuh_layer_id equal to layer_id_in_nuh[j]. max_tid_il_ref_pics_plus1[i][j] greater than 0 specifies that within the CVS pictures with nuh_layer_id equal to layer_id_in_nuh[i] and TemporalId greater than max_tid_il_ref_pics_plus1[i][j]−1 are not used as reference for inter-layer prediction for pictures with nuh_layer_id equal to layer_id_in_nuh[j]. When not present, max_tid_il_ref_pics_plus1[i][j] is inferred to be equal to 7. all_ref_layers_active_flag equal to 1 specifies that for each picture referring to the VPS, the reference layer pictures that belong to all direct reference layers of the layer containing the picture and that might be used for inter-layer prediction as specified by the values of sub_layers_vps_max_minus1[i] and max_tid_il_ref_pics_plus1[i][j] are present in the same access unit as the picture and are included in the inter-layer reference picture set of the picture. all_ref layers_active_flag equal to 0 specifies that the above restriction may or may not apply. max_one_active_ref_layer_flag equal to 1 specifies that at most one picture is used for inter-layer prediction for each picture in the CVS. max_one_active_ref_layer_flag equal to 0 specifies that more than one picture may be used for inter-layer prediction for each picture in the CVS. A layer tree may be defined as a set of layers such that each layer in the set of layers is a direct or indirected predicted layer or a direct or indirect reference layer of at least one other layer in the set of layers and no layer outside to the set of layers is a direct or indirected predicted layer or a direct or indirect reference layer of any layer in the set of layers. A direct predicted layer may be defined as a layer for which another layer is a direct reference layer. A direct reference layer may be defined as a layer that may be used for inter-layer prediction of another layer for which the layer is the direct reference layer. An indirect predicted layer may be defined as a layer for which another layer is an indirect reference layer. An indirect reference layer may be defined as a layer that is not a direct reference layer of a second layer but is a direct reference layer of a third layer that is a direct reference layer or indirect reference layer of a direct reference layer of the second layer for which the layer is the indirect reference layer. Alternatively, a layer tree may be defined as a set of layers where each layer has an inter-layer prediction relation with at least one other layer in the layer tree and no layer outside the layer tree has an inter-layer prediction relation with any layer in the layer tree. In SHVC, MV-HEVC, and/or alike, the block level syntax and decoding process are not changed for supporting interlayer texture prediction. Only the high-level syntax, generally referring to the syntax structures including slice header, PPS, SPS, and VPS, has been modified (compared to that of HEVC) so that reconstructed pictures (up sampled if necessary) from a reference layer of the same access unit can be used as the reference pictures for coding the current enhancement layer picture. The inter-layer reference pictures as well as the temporal reference pictures are included in the reference picture lists. The signalled reference picture index is used to indicate whether the current Prediction Unit (PU) is predicted from a temporal reference picture or an inter-layer reference picture. The use of this feature may be controlled by the encoder and indicated in the bitstream for example in a video parameter set, a sequence parameter set, a picture parameter, and/or a slice header. The indication(s) may be specific to an enhancement layer, a reference layer, a pair of an enhancement layer and a reference layer, specific TemporalId values, specific picture types (e.g. RAP pictures), specific slice types (e.g. P and B slices but not I slices), pictures of a specific POC value, and/or specific access units, for example. The scope and/or persistence of the indication(s) may be indicated along with the indication(s) themselves and/or may be inferred. The reference list(s) in SHVC, MV-HEVC, and/or alike may be initialized using a specific process in which the inter-layer reference picture(s), if any, may be included in the initial reference picture list(s). For example, the temporal references may be firstly added into the reference lists (L0, L1) in the same manner as the reference list construction in HEVC. After that, the inter-layer references may be added after the temporal references. The inter-layer reference pictures may be for example concluded from the layer dependency information provided in the VPS extension. The inter-layer reference pictures may be added to the initial reference picture list L0if the current enhancement-layer slice is a P-Slice, and may be added to both initial reference picture lists L0and L1if the current enhancement-layer slice is a B-Slice. The inter-layer reference pictures may be added to the reference picture lists in a specific order, which can but need not be the same for both reference picture lists. For example, an opposite order of adding inter-layer reference pictures into the initial reference picture list 1 may be used compared to that of the initial reference picture list 0. For example, inter-layer reference pictures may be inserted into the initial reference picture 0 in an ascending order of nuh_layer_id, while an opposite order may be used to initialize the initial reference picture list 1. A second example of constructing reference picture list(s) is provided in the following. Candidate inter-layer reference pictures may be for example concluded from the layer dependency information, which may be included in the VPS, for example. The encoder may include picture-level information in a bitstream and the decoder may decode picture-level information from the bitstream which ones of the candidate inter-layer reference pictures may be used as reference for inter-layer prediction. The picture-level information may for example reside in a slice header and may be referred to as an inter-layer reference picture set. For example, the candidate inter-layer reference pictures may be indexed in a certain order and one or more indexes may be included in the inter-layer reference picture set. In another example, a flag for each candidate inter-layer reference picture indicates if it may be used as an inter-layer reference picture. As above, the inter-layer reference pictures may be added to the initial reference picture list L0if the current enhancement-layer slice is a P-Slice, and may be added to both initial reference picture lists L0and L1if the current enhancement-layer slice is a B-Slice. The inter-layer reference pictures may be added to the reference picture lists in a specific order, which can but need not be the same for both reference picture lists. A third example of constructing reference picture list(s) is provided in the following. In the third example, an interlayer reference picture set is specified in the slice segment header syntax structure as follows: Descriptorslice_segment_header( ) {...if(nuh_layer_id > 0 &&!all_ref_layers_active_flag&&NumDirectRefLayers[ nuh_layer_id ] > 0 ) {inter_layer_pred_enabled_flagu(1)if( inter_layer_pred_enabled_flag &&NumDirectRefLayers[ nuh_layer_id ] > 1) {if( !max_one_active_ref_layer_flag )num_inter_layer_ref_pics_minus1u(v)if( NumActiveRefLayerPics !=NumDirectRefLayers[ nuh_layer_id ] )for( i = 0; i <NumActiveRefLayerPics; i++ )inter_layer_pred_layer_idc[ i ]u(v)}}... The variable NumDirectRefLayers[layerId] has been derived to be the number of direct reference layers for the layer with nuh_layer_id equal to layerId based on the layer dependency information. In the context of MV-HEVC, SHVC, and alike, NumDirectRefLayers[layerId] may be derived based on the direct_dependency_flag[i][j] syntax elements of VPS. The semantics of the above excerpt of the slice segment header syntax structure may be specified as described in the following paragraphs. inter_layer_pred_enabled_flag equal to 1 specifies that inter-layer prediction may be used in decoding of the current picture. inter_layer_pred_enabled_flag equal to 0 specifies that inter-layer prediction is not used in decoding of the current picture. num_inter_layer_ref_pics_minus1 plus 1 specifies the number of pictures that may be used in decoding of the current picture for inter-layer prediction. The length of the num_inter_layer_ref_pics_minus1 syntax element is Ceil (Log 2(NumDirectRefLayers[nuh_layer_id])) bits. The value of num_inter_layer_ref_pics_minus1 shall be in the range of 0 to NumDirectRefLayers[nuh_layer_id]−1, inclusive. The variables numRefLayerPics and refLayerPicIdc[j] may be derived as follows: for( i = 0, j = 0; i < NumDirectRefLayers[ nuh_layer_id ]; i++ ) {refLayerIdx = LayerIdxInVps[ RefLayerId[ nuh_layer_id ][ i ] ]if( sub_layers_vps_max_minus1[ refLayerIdx ] >= TemporalId &&max_tid_il_ref_pics_plus1[ refLayerIdx ][ LayerIdxInVps[ nuh_layer_id ] ] > TemporalId )refLayerPicIdc[ j++ ] = i}numRefLayerPics = j The list refLayerPicIdc[j] may be considered to indicate the candidate inter-layer reference pictures with reference to the second example above. The variable NumActiveRefLayerPics may be derived as follows: if( nuh_layer_id = = 0 || NumDirectRefLayers[ nuh_layer_id ] = = 0 )NumActiveRefLayerPics = 0else if( all_ref_layers_active_flag )NumActiveRefLayerPics = numRefLayerPicselse if( !inter_layer_pred_enabled_flag )NumActiveRefLayerPics = 0else if( max_one_active_ref_layer_flag ||NumDirectRefLayers[ nuh_layer_id ] = = 1 )NumActiveRefLayerPics = 1elseNumActiveRefLayerPics = num_inter_layer_ref_pics_minus1 + 1 inter_layer_pred_layer_idc[i] specifies the variable, RefPicLayerId[i], representing the nuh_layer_id of the i-th picture that may be used by the current picture for inter-layer prediction. The length of the syntax element inter_layer_pred_layer_idc[i] is Ceil(Log 2(NumDirectRefLayers[nuh_layer_id])) bits. The value of inter_layer_pred_layer_idc[i] shall be in the range of 0 to NumDirectRefLayers[nuh_layer_id]−1, inclusive. When not present, the value of inter_layer_pred_layer_idc[i] is inferred to be equal to refLayerPicIdc[i]. The variables RefPicLayerId[i] for all values of i in the range of 0 to NumActiveRefLayerPics−1, inclusive, are derived as follows: for( i = 0, j = 0; i < NumActiveRefLayerPics; i++)RefPicLayerId[ i ] = RefLayerId[ nuh_layer_id ][ inter_layer_pred_layer_idc[ i ] ] inter_layer_pred_layer_idc[i] may be considered to be picture-level information which ones of the candidate interlayer reference pictures may be used as reference for interlayer prediction, with reference to the second example above. The pictures identified by variable RefPicLayerId[i] for all values of i in the range of 0 to NumActiveRefLayerPics−1, inclusive, may be included in initial reference picture lists. As above, the pictures identified by variable RefPicLayerId[i] may be added to the initial reference picture list L0if the current enhancement-layer slice is a P-Slice, and may be added to both initial reference picture lists L0and L1if the current enhancement-layer slice is a B-Slice. The pictures identified by variable RefPicLayerId[i] may be added to the reference picture lists in a specific order, which can but need not be the same for both reference picture lists. For example, the derived ViewId values may affect the order of adding the pictures identified by variable RefPicLayerId[i] into the initial reference picture lists. In the coding and/or decoding process, the inter-layer reference pictures may be treated as long term reference pictures. A type of inter-layer prediction, which may be referred to as inter-layer motion prediction, may be realized as follows. A temporal motion vector prediction process, such as TMVP of H.265/HEVC, may be used to exploit the redundancy of motion data between different layers. This may be done as follows: when the decoded base-layer picture is upsampled, the motion data of the base-layer picture is also mapped to the resolution of an enhancement layer. If the enhancement layer picture utilizes motion vector prediction from the base layer picture e.g. with a temporal motion vector prediction mechanism such as TMVP of H.265/HEVC, the corresponding motion vector predictor is originated from the mapped base-layer motion field. This way the correlation between the motion data of different layers may be exploited to improve the coding efficiency of a scalable video coder. In SHVC and/or alike, inter-layer motion prediction may be performed by setting the inter-layer reference picture as the collocated reference picture for TMVP derivation. A motion field mapping process between two layers may be performed for example to avoid block level decoding process modification in TMVP derivation. The use of the motion field mapping feature may be controlled by the encoder and indicated in the bitstream for example in a video parameter set, a sequence parameter set, a picture parameter, and/or a slice header. The indication(s) may be specific to an enhancement layer, a reference layer, a pair of an enhancement layer and a reference layer, specific TemporalId values, specific picture types (e.g. RAP pictures), specific slice types (e.g. P and B slices but not I slices), pictures of a specific POC value, and/or specific access units, for example. The scope and/or persistence of the indication(s) may be indicated along with the indication(s) themselves and/or may be inferred. In a motion field mapping process for spatial scalability, the motion field of the upsampled inter-layer reference picture may be attained based on the motion field of the respective reference layer picture. The motion parameters (which may e.g. include a horizontal and/or vertical motion vector value and a reference index) and/or a prediction mode for each block of the up sampled inter-layer reference picture may be derived from the corresponding motion parameters and/or prediction mode of the collocated block in the reference layer picture. The block size used for the derivation of the motion parameters and/or prediction mode in the upsampled inter-layer reference picture may be for example 16×16. The 16×16 block size is the same as in HEVC TMVP derivation process where compressed motion field of reference picture is used. As discussed above, in HEVC, a two-byte NAL unit header is used for all specified NAL unit types. The NAL unit header contains one reserved bit, a six-bit NAL unit type indication (called nal_unit_type), a six-bit reserved field (called nuh_layer_id) and a three-bit temporal_id_plus1 indication for temporal level. The temporal_id_plus1 syntax element may be regarded as a temporal identifier for the NAL unit, and a zero-based TemporalId variable may be derived as follows: TemporalId=temporal_id_plus1−1. TemporalId equal to 0 corresponds to the lowest temporal level. The value of temporal_id_plus1 is required to be non-zero in order to avoid start code emulation involving the two NAL unit header bytes. The bitstream created by excluding all VCL NAL units having a TemporalId greater than or equal to a selected value and including all other VCL NAL units remains conforming. Consequently, a picture having TemporalId equal to TID does not use any picture having a TemporalId greater than TID as inter prediction reference. A sub-layer or a temporal sub-layer may be defined to be a temporal scalable layer of a temporal scalable bitstream, consisting of VCL NAL units with a particular value of the TemporalId variable and the associated non-VCL NAL units. In HEVC extensions nuh_layer_id and/or similar syntax elements in NAL unit header carries scalability layer information. For example, the LayerId value nuh_layer_id and/or similar syntax elements may be mapped to values of variables or syntax elements describing different scalability dimensions. In scalable and/or multiview video coding, at least the following principles for encoding pictures and/or access units with random access property may be supported.An IRAP picture within a layer may be an intra-coded picture without inter-layer/inter-view prediction. Such a picture enables random access capability to the layer/view it resides.An IRAP picture within an enhancement layer may be a picture without inter prediction (i.e. temporal prediction) but with inter-layer/inter-view prediction allowed. Such a picture enables starting the decoding of the layer/view the picture resides provided that all the reference layers/views are available. In single-loop decoding, it may be sufficient if the coded reference layers/views are available (which can be the case e.g. for IDR pictures having dependency_id greater than 0 in SVC). In multi-loop decoding, it may be needed that the reference layers/views are decoded. Such a picture may, for example, be referred to as a stepwise layer access (STLA) picture or an enhancement layer IRAP picture.An anchor access unit or a complete IRAP access unit may be defined to include only intra-coded picture(s) and STLA pictures in all layers. In multi-loop decoding, such an access unit enables random access to all layers/views. An example of such an access unit is the MVC anchor access unit (among which type the IDR access unit is a special case).A stepwise IRAP access unit may be defined to include an IRAP picture in the base layer but need not contain an IRAP picture in all enhancement layers. A stepwise IRAP access unit enables starting of base-layer decoding, while enhancement layer decoding may be started when the enhancement layer contains an IRAP picture, and (in the case of multi-loop decoding) all its reference layers/views are decoded at that point. In a scalable extension of HEVC or any scalable extension for a single-layer coding scheme similar to HEVC, IRAP pictures may be specified to have one or more of the following properties.NAL unit type values of the IRAP pictures with nuh_layer_id greater than 0 may be used to indicate enhancement layer random access points.An enhancement layer IRAP picture may be defined as a picture that enables starting the decoding of that enhancement layer when all its reference layers have been decoded prior to the EL IRAP picture.Inter-layer prediction may be allowed for IRAP NAL units with nuh_layer_id greater than 0, while inter prediction is disallowed.IRAP NAL units need not be aligned across layers. In other words, an access unit may contain both IRAP pictures and non-IRAP pictures.After a BLA picture at the base layer, the decoding of an enhancement layer is started when the enhancement layer contains an IRAP picture and the decoding of all of its reference layers has been started. In other words, a BLA picture in the base layer starts a layer-wise start-up process.When the decoding of an enhancement layer starts from a CRA picture, its RASL pictures are handled similarly to RASL pictures of a BLA picture (in HEVC version 1). Scalable bitstreams with IRAP pictures or similar that are not aligned across layers may be used for example more frequent IRAP pictures can be used in the base layer, where they may have a smaller coded size due to e.g. a smaller spatial resolution. A process or mechanism for layer-wise start-up of the decoding may be included in a video decoding scheme. Decoders may hence start decoding of a bitstream when a base layer contains an IRAP picture and step-wise start decoding other layers when they contain IRAP pictures. In other words, in a layer-wise start-up of the decoding process, decoders progressively increase the number of decoded layers (where layers may represent an enhancement in spatial resolution, quality level, views, additional components such as depth, or a combination) as subsequent pictures from additional enhancement layers are decoded in the decoding process. The progressive increase of the number of decoded layers may be perceived for example as a progressive improvement of picture quality (in case of quality and spatial scalability). A layer-wise start-up mechanism may generate unavailable pictures for the reference pictures of the first picture in decoding order in a particular enhancement layer. Alternatively, a decoder may omit the decoding of pictures preceding, in decoding order, the IRAP picture from which the decoding of a layer can be started. These pictures that may be omitted may be specifically labeled by the encoder or another entity within the bitstream. For example, one or more specific NAL unit types may be used for them. These pictures, regardless of whether they are specifically marked with a NAL unit type or inferred e.g. by the decoder, may be referred to as cross-layer random access skip (CL-RAS) pictures. The decoder may omit the output of the generated unavailable pictures and the decoded CL-RAS pictures. A layer-wise start-up mechanism may start the output of enhancement layer pictures from an IRAP picture in that enhancement layer, when all reference layers of that enhancement layer have been initialized similarly with an IRAP picture in the reference layers. In other words, any pictures (within the same layer) preceding such an IRAP picture in output order might not be output from the decoder and/or might not be displayed. In some cases, decodable leading pictures associated with such an IRAP picture may be output while other pictures preceding such an IRAP picture might not be output. Concatenation of coded video data. which may also be referred to as splicing, may occur for example coded video sequences are concatenated into a bitstream that is broadcast or streamed or stored in a mass memory. For example, coded video sequences representing commercials or advertisements may be concatenated with movies or other “primary” content. Scalable video bitstreams might contain IRAP pictures that are not aligned across layers. It may, however, be convenient to enable concatenation of a coded video sequence that contains an IRAP picture in the base layer in its first access unit but not necessarily in all layers. A second coded video sequence that is spliced after a first coded video sequence should trigger a layer-wise decoding start-up process. That is because the first access unit of said second coded video sequence might not contain an IRAP picture in all its layers and hence some reference pictures for the non-IRAP pictures in that access unit may not be available (in the concatenated bitstream) and cannot therefore be decoded. The entity concatenating the coded video sequences, hereafter referred to as the splicer, should therefore modify the first access unit of the second coded video sequence such that it triggers a layer-wise start-up process in decoder(s). Indication(s) may exist in the bitstream syntax to indicate triggering of a layer-wise start-up process. These indication(s) may be generated by encoders or splicers and may be obeyed by decoders. These indication(s) may be used for particular picture type(s) or NAL unit type(s) only, such as only for IDR pictures. while in other embodiments these indication(s) may be used for any picture type(s). Without loss of generality, an indication called cross_layer_bla_flag that is considered to be included in a slice segment header is referred to below. It should be understood that a similar indication with any other name or included in any other syntax structures could be additionally or alternatively used. Independently of indication(s) triggering a layer-wise start-up process, certain NAL unit type(s) and/or picture type(s) may trigger a layer-wise start-up process. For example, a base-layer BLA picture may trigger a layer-wise start-up process. A layer-wise start-up mechanism may be initiated in one or more of the following cases:At the beginning of a bitstream.At the beginning of a coded video sequence, when specifically controlled, e.g. when a decoding process is started or re-started e.g. as response to tuning into a broadcast or seeking to a position in a file or stream. The decoding process may input an variable, e.g. referred to as NoClrasOutputFlag, that may be controlled by external means, such as the video player or alike.A base-layer BLA picture.A base-layer IDR picture with cross_layer_bla_flag equal to 1. (Or a base-layer IRAP picture with cross_layer_bla_flag equal to 1.) When a layer-wise start-up mechanism is initiated, all pictures in the DPB may be marked as “unused for reference”. In other words, all pictures in all layers may be marked as “unused for reference” and will not be used as a reference for prediction for the picture initiating the layer-wise start-up mechanism or any subsequent picture in decoding order. Cross-layer random access skipped (CL-RAS) pictures may have the property that when a layer-wise start-up mechanism is invoked (e.g. when NoClrasOutputFlag is equal to 1), the CL-RAS pictures are not output and may not be correctly decodable, as the CL-RAS picture may contain references to pictures that are not present in the bitstream. It may be specified that CL-RAS pictures are not used as reference pictures for the decoding process of non-CL-RAS pictures. CL-RAS pictures may be explicitly indicated e.g. by one or more NAL unit types or slice header flags (e.g. by re-naming cross_layer_bla_flag to cross_layer_constraint_flag and re-defining the semantics of cross_layer_bla_flag for non-IRAP pictures). A picture may be considered as a CL-RAS picture when it is a non-IRAP picture (e.g. as determined by its NAL unit type), it resides in an enhancement layer and it has cross_layer_constraint_flag (or similar) equal to 1. Otherwise, a picture may be classified of being a non-CL-RAS picture. cross_layer_bla_flag may be inferred to be equal to 1 (or a respective variable may be set to 1), if the picture is an IRAP picture (e.g. as determined by its NAL unit type), it resides in the base layer, and cross_layer_constraint_flag is equal to 1. Otherwise, cross_layer_bla_flag may inferred to be equal to 0 (or a respective variable may be set to 0). Alternatively, CL-RAS pictures may be inferred. For example, a picture with nuh_layer_id equal to layerId may be inferred to be a CL-RAS picture when the LayerInitializedFlag[layerId] is equal to 0. A CL-RAS picture may be defined as a picture with nuh_layer_id equal to layerId such that LayerInitializedFlag[layerId] is equal to 0 when the decoding of a coded picture with nuh_layer_id greater than 0 is started. A decoding process may be specified in a manner that a certain variable controls whether or not a layer-wise start-up process is used. For example, a variable NoClrasOutputFlag may be used, which, when equal to 0, indicates a normal decoding operation, and when equal to 1, indicates a layer-wise start-up operation. NoClrasOutputFlag may be set for example using one or more of the following steps:1) If the current picture is an IRAP picture that is the first picture in the bitstream. NoClrasOutputFlag is set equal to 1.2) Otherwise, if some external means are available to set the variable NoClrasOutputFlag equal to a value for a base-layer IRAP picture, the variable NoClrasOutputFlag is set equal to the value provided by the external means.3) Otherwise, if the current picture is a BLA picture that is the first picture in a coded video sequence (CVS), NoClrasOutputFlag is set equal to 1.4) Otherwise, if the current picture is an IDR picture that is the first picture in a coded video sequence (CVS) and cross_layer_bla_flag is equal to 1, NoClrasOutputFlag is set equal to 1.5) Otherwise, NoClrasOutputFlag is set equal to 0. Step 4 above may alternatively be phrased more generally for example as follows: “Otherwise, if the current picture is an IRAP picture that is the first picture in a CVS and an indication of layer-wise start-up process is associated with the IRAP picture, NoClrasOutputFlag is set equal to 1.” Step 3 above may be removed, and the BLA picture may be specified to initiate a layer-wise start-up process (i.e. set NoClrasOutputFlag equal to 1). when cross_layer_bla_flag for it is equal to 1. It should be understood that other ways to phrase the condition are possible and equally applicable. A decoding process for layer-wise start-up may be for example controlled by two array variables LayerInitializedFlag[i] and FirstPicInLayerDecodedFlag[i] which may have entries for each layer (possibly excluding the base layer and possibly other independent layers too). When the layer-wise start-up process is invoked, for example as response to NoClrasOutputFlag being equal to 1, these array variables may be reset to their default values. For example, when there 64 layers are enabled (e.g. with a 6-bit nuh_layer_id), the variables may be reset as follows: the variable LayerInitializedFlag[i] is set equal to 0 for all values of i from 0 to 63, inclusive, and the variable FirstPicInLayerDecodedFlag[i] is set equal to 0 for all values of i from 1 to 63, inclusive. The decoding process may include the following or similar to control the output of RASL pictures. When the current picture is an IRAP picture, the following applies:If LayerInitializedFlag[nuh_layer_id] is equal to 0, the variable NoRas1OutputFlag is set equal to 1.Otherwise, if some external means is available to set the variable HandleCraAsBlaFlag to a value for the current picture, the variable HandleCraAsBlaFlag is set equal to the value provided by the external means and the variable NoRas1OutputFlag is set equal to HandleCraAsBlaFlag.Otherwise, the variable HandleCraAsBlaFlag is set equal to 0 and the variable NoRas1OutputFlag is set equal to 0. The decoding process may include the following to update the LayerInitializedFlag for a layer. When the current picture is an IRAP picture and either one of the following is true, LayerInitializedFlag[nuh_layer_id] is set equal to 1.nuh_layer_id is equal to 0.LayerInitializedFlag[nuh_layer_id] is equal to 0 and LayerInitializedFlag[refLayerId] is equal to 1 for all values of refLayerId equal to RefLayerId[nuh_layer_id][j], where j is in the range of 0 to NumDirectRefLayers [nuh_layer_id]−1, inclusive. When FirstPicInLayerDecodedFlag[nuh_layer_id] is equal to 0, the decoding process for generating unavailable reference pictures may be invoked prior to decoding the current picture. The decoding process for generating unavailable reference pictures may generate pictures for each picture in a reference picture set with default values. The process of generating unavailable reference pictures may be primarily specified only for the specification of syntax constraints for CL-RAS pictures, where a CL-RAS picture may be defined as a picture with nuh_layer_id equal to layerId and LayerInitializedFlag[layerId] is equal to 0. In HRD operations, CL-RAS pictures may need to be taken into consideration in derivation of CPB arrival and removal times. Decoders may ignore any CL-RAS pictures, as these pictures are not specified for output and have no effect on the decoding process of any other pictures that are specified for output. Picture output in scalable coding may be controlled for example as follows: For each picture PicOutputFlag is first derived in the decoding process similarly as for a single-layer bitstream. For example, pic_output_flag included in the bitstream for the picture may be taken into account in the derivation of PicOutputFlag. When an access unit has been decoded, the output layers and possible alternative output layers are used to update PicOutputFlag for each picture of the access unit, for example as follows:If the use of an alternative output layer has been enabled (e.g. AltOptLayerFlag[TargetOptLayerSetIdx] is equal to 1 in draft MV-HEVC/SHVC) and an access unit either does not contain a picture at the target output layer or contains a picture at the target output layer that has PicOutputFlag equal to 0, the following ordered steps apply:The list nonOutputLayerPictures is the list of the pictures of the access unit with PicOutputFlag equal to 1 and with nuh_layer_id values among the nuh_layer_id values of the direct and indirect reference layers of the target output layer.The picture with the highest nuh_layer_id value among the list nonOutputLayerPictures is removed from the list nonOutputLayerPictures.PicOutputFlag for each picture that is included in the list nonOutputLayerPictures is set equal to 0.Otherwise, PicOutputFlag for pictures that are not included in a target output layer is set equal to 0. Alternatively, the condition above to trigger the output of a picture from an alternative output layer may be constrained to concern only CL-RAS pictures rather than all pictures with PicOutputFlag equal to 0. In other words, the condition may be phrased as follows:If the use of an alternative output layer has been enabled (e.g. AltOptLayerFlag[TargetOptLayerSetIdx] is equal to 1 in draft MV-HEVC/SHVC) and an access unit either does not contain a picture at the target output layer or contains a CL-RAS picture at the target output layer that has PicOutputFlag equal to 0, the following ordered steps apply: Alternatively, the condition may be phrased as follows:If the use of an alternative output layer has been enabled (e.g. AltOptLayerFlag[TargetOptLayerSetIdx] is equal to 1 in draft MV-HEVC/SHVC) and an access unit either does not contain a picture at the target output layer or contains a picture with PicOutputFlag equal to 0 at the target output layer lId such that LayerInitializedFlag[lId] is equal to 0, the following ordered steps apply: However, the scalability designs in the contemporary state of the above-described video coding standards have some limitations. For example, in SVC and SHVC, pictures (or alike) of an access unit are required to have the same temporal level (e.g. TemporalId value in HEVC and its extensions). This has the consequence that it disables encoders to determine prediction hierarchies differently across layers. Different prediction hierarchies across layers could be used to encode some layers with a greater number of TemporalId values and frequent sub-layer up-switch points and some layers with a prediction hierarchy aiming at a better rate-distortion performance. Moreover, encoders are not able to encode layer trees of the same bitstream independently from each other. For example, the base layer and an auxiliary picture layer could be encoded by different encoders, and/or encoding of different layer trees could take place at different times. However, presently layers are required to have the same (de)coding order and TemporalId of respective pictures. A further limitation, for example in SVC and SHVC, is that temporal level switch pictures, such as TSA and STSA pictures of HEVC and its extensions, are not allowed the lowest temporal level, such as TemporalId equal to 0 in HEVC and its extensions. This has the consequence that it disables to indicate an access picture or access point to a layer that enables decoding of some temporal levels (but not necessarily all of them). However, such an access point could be used, for example, for step-wise start-up of decoding of a layer in a sub-layer-wise manner and/or bitrate adaptation. Now in order to at least alleviate the above problems, methods for encoding and decoding restricted layer access pictures are presented hereinafter. In the encoding method, which is disclosed inFIG.7, a first picture is encoded (750) on a first scalability layer and on a lowest temporal sub-layer, and a second picture is encoded (752) on a second scalability layer and on the lowest temporal sub-layer, wherein the first picture and the second picture represent the same time instant. Then one or more first syntax elements, associated with the first picture, are encoded (754) with a value indicating that a picture type of the first picture is other than a step-wise temporal sub-layer access picture. Similarly, one or more second syntax elements, associated with the second picture, are encoded (756) with a value indicating that a picture type of the second picture is a step-wise temporal sub-layer access picture. Then at least a third picture is encoded (758) on a second scalability layer and on a temporal sub-layer higher than the lowest temporal sub-layer. According to an embodiment, the step-wise temporal sub-layer access picture provides an access point for layer-wise initialization of decoding of a bitstream with one or more temporal sub-layers. Thus, the encoder encodes an access picture or access point to a layer, wherein the access picture or the access point enables decoding of some temporal sub-layers (but not necessarily all of them). Such an access point may be used for example for step-wise start-up of decoding of a layer in a sub-layer-wise manner (e.g. by a decoder) and/or bitrate adaptation (e.g. by a sender), as will be described further below. According to an embodiment, the step-wise temporal sub-layer access picture is an STSA picture with TemporalId equal to 0. FIG.8illustrates an example, where an STSA picture with TemporalId equal to 0 is used to indicate a restricted layer access picture. InFIG.8, both the base layer (BL) and the enhancement layer (EL) comprise pictures on four temporal sub-layers (TemporalId (TID)=0, 1, 2, 3). The decoding order of the pictures is 0, 1, . . . , 9, A, B, C, . . . , whereas the output order of the pictures is the order of pictures from left to right inFIG.8. The decoded picture buffer (DPB) state or DPB dump for each picture inFIG.8and subsequent figures shows the decoded pictures which are marked as “used for reference”. In other words, the DPB dump considers pictures marked as “used for reference” but does not consider pictures marked as “needed for output” (which might have already been marked “unused for reference”). The DPB state may include the following pictures:the picture in question being encoded or decoded (the bottom-most item in the indicated DPB state inFIG.8and in subsequent figures);the pictures which are not used as reference for encoding (and decoding) the picture in question but may be used as reference for encoding (and decoding) subsequent pictures in decoding order (the items in the indicated DPB state with italics and underlining inFIG.8and subsequent figures); andthe pictures that may be used as reference for encoding (and decoding) the picture in question (all other items in the indicated DPB state inFIG.8and subsequent figures). The EL picture 1 is a layer access picture that provides access to sub-layers with TemporalId 0, 1, and 2 but does not provide access to sub-layer with TemporalId equal to 3. In this example there are no TSA or STSA pictures among the presented pictures (5,7,8, C, D, F, G) of TID 3 of the EL. According to an embodiment, the method further comprises signaling the step-wise temporal sub-layer access picture in the bitstream by a specific NAL unit type. Thus, rather than re-using the STSA nal_unit_type, a specific NAL unit type may be taken into use and may be referred to sub-layer-constrained layer access picture. According to an embodiment, the method further comprises signaling the step-wise temporal sub-layer access picture with an SEI message. The SEI message may also define the number of decodable sub-layers. The SEI message can be used in addition to or instead of using a NAL unit type indicating a sub-layer-constrained layer access picture or an STSA picture with TemporalId equal to 0. The SEI message may also include the number of sub-layers that can be decoded (at full picture rate) when the decoding of the layer starts from the associated layer access picture. For example, referring to the example inFIG.8, the EL picture 1, which is a layer access picture, may be indicated to provide access to three sub-layers (TID 0, 1, 2). According to an embodiment, the method further comprises encoding said second or any further scalability layer to comprise more frequent TSA or STSA pictures than the first scalability layer. Thereby. a sender or a decoder or alike may determine dynamically and in a layer-wise manner how many sub-layers are transmitted or decoded. When the enhancement layer contains more frequent TSA or STSA pictures than in the base layer, finer-grain bitrate adjustment can be performed than what can be achieved by determining the number of layers and/or the number sub-layers orthogonally. It is remarked that when the alternative output layer mechanism is in use and there is no picture at the target output layer, a picture from the lower layer is to be output. Consequently, even if pictures from the target output layer are omitted from transmission, the output picture rate (of a decoder) may remain unchanged. FIG.9illustrates an example when the base layer BL has fewer TSA pictures (pictures2,3,4) than the enhancement layer EL (pictures2,3,4,5,7,8, A, B, C, D, F, G). It is remarked that some prediction arrows from TID0 pictures are not included in the illustration (but can be concluded from the DPB dump). According to an embodiment, it is possible to encode non-aligned temporal sub-layer access pictures when only certain temporal levels are used for inter-layer prediction. In this use case, it is assumed that pictures of only some TemporalId values are used as reference for inter-layer prediction, which may be indicated in a sequence-level syntax structure, such as using the max_tid_il_ref_pics_plus1 syntax element of the VPS extension of MV-HEVC, SHVC and/or alike. It is further assumed that the sender knows that the receiver uses an output layer set, where only the EL is output. Consequently, the sender omits the transmission of BL pictures with a TemporalId value such that it is indicated not to be used as reference for inter-layer prediction. It is further assumed that the sender performs bitrate adjustment or bitrate adaptation by selecting adaptively the maximum TemporalId that is transmitted from the EL. FIG.10shows an example, which is similar to the example inFIG.9, but where BL pictures with TemporalId greater than or equal to 2 are not used as reference for inter-layer prediction, i.e. in MV-HEVC, SHVC, and/or alike this may be indicated by setting the max_tid_il_ref pics_plus1 syntax element between the base and enhancement layer equal to 2. According to an embodiment, which may be applied together with or independently of other embodiments, it is possible to encode non-aligned temporal sub-layer access pictures when TemporalId need not be aligned across layers in the same access unit. This may be utilized, for example, in scalable video coding schemes allowing pictures with different TemporalId values (or alike) in the same access unit. Having different TemporalId values for pictures in the same access unit may enable providing encoders flexibility in determining prediction hierarchies differently across layers, allowing some layers to be coded with a greater number of TemporalId values and frequent sub-layer up-switch points and some layers with a prediction hierarchy aiming at a better rate-distortion performance. Moreover, it provides flexibility to encode layer trees of the same bitstream independently from each other. For example, the base layer and an auxiliary picture layer could be encoded by different encoders, and/or encoding of different layer trees could take place at different times. By allowing encoders to operate independently from each other, the encoders have flexibility in determining a prediction hierarchy and the number of TemporalId values used according to the input signal. The encoder may indicate e.g. in a sequence-level syntax structures, such as VPS, whether TemporalId values or alike are aligned (i.e., the same) for coded pictures within an access unit. The decoder may decode e.g. from a sequence-level syntax structure, such as VPS, an indication whether TemporalId values or alike are aligned for coded pictures within an access unit. On the basis of TemporalId values or alike being aligned for coded pictures within an access unit, the encoder and/or the decoder may choose different syntax, semantics, and/or operation than when TemporalId values or alike might not be aligned for coded pictures within an access unit. For example, when TemporalId values or alike are aligned for coded pictures within an access unit, interlayer RPS syntax, semantics, and/or derivation in the encoding and/or the decoding may utilize information which TemporalId values the pictures used as reference for interlayer predication between a reference layer and a predicted layer may have and/or which TemporalId values the pictures used as reference for inter-layer predication between a reference layer and a predicted layer are not allowed have. For example, a syntax element called tid_aligned_flag may be included in the VPS and its semantics may be specified as follows: tid_aligned_flag equal to 0 specifies that TemporalId may or may not be the same for different coded pictures of the same access unit. tid_aligned_flag equal to 1 specifies that TemporalId is the same for all coded pictures of the same access unit. The tid_aligned_flag may be taken into account in deriving a list of candidate inter-layer reference pictures. For example, with reference to the above-described third example of constructing reference picture list(s), the pseudo-code to specify a list identifying candidate inter-layer reference pictures, refLayerPicIdc[ ] may be specified as follows: for( i = 0, j = 0; i < NumDirectRefLayers[ nuh_layer_id ]; i++ ) {refLayerIdx = LayerIdxInVps[ RefLayerId[ nuh_layer_id ][ i ] ]if( sub_layers_vps_max_minus1[ refLayerIdx ] >= TemporalId &&( max_tid_il_ref_pics_plus1[ refLayerIdx ][ LayerIdxInVps[ nuh_layer_id ] ] > TemporalId|| !tid_aligned_flag ) )refLayerPicIdc[ j++ ] = i}numRefLayerPics = j When TemporalId values are indicated to be aligned for all pictures in an access unit, the indicated maximum TemporalId value that may be used for inter-layer prediction affects the derivation of a list of candidate inter-layer reference pictures, i.e. only the pictures with a smaller or equal TemporalId value than the indicated maximum TemporalId value are included in the list of candidate inter-layer reference pictures. When TemporalId values may or may not be aligned for all pictures in an access unit, pictures of any TemporalId values are included in the list of candidate inter-layer reference pictures. FIG.11shows an example where prediction hierarchies are determined differently across layers. In this example, the base layer (BL) is coded with a hierarchical prediction hierarchy in which codes all pictures with TemporalId of all pictures is equal to0. It is assumed that the prediction hierarchy used in the BL has been used to obtain a good rate-distortion performance for the base layer. The enhancement layer (EL) has four sub-layers and frequent TSA pictures, which provide the capability of dynamically selecting how many sub-layers are transmitted for the EL. Similarly toFIG.9, it is remarked that some prediction arrows from EL TID0 pictures are not included in the illustration ofFIG.11(but can be concluded from the DPB dump). Likewise. the BL prediction arrows are excluded and can be concluded from the DPB dump. An embodiment, which may be applied together with or independent of other embodiments, is described next. With reference to the presented examples of VPS syntax and semantics as well as the above-described third example of constructing reference picture list(s), the following issues have been identified:When a list identifying candidate inter-layer reference pictures, refLayerPicIdc[ ] is derived. the condition “max_tid_il_ref_pics_plus1[refLayerIdx][LayerIdxInVps[nuh_layer_id]]>TemporalId” has the consequence that when max_tid_il_ref_pics_plus1[refLayerIdx][LayerIdxInVps[nuh_layer_id]] is equal to0(i.e., when only the IRAP pictures of the reference layer may be used as reference for inter-layer prediction), the index of the reference layer is not included in refLayerPic Idc[ ].max_tid_il_ref_pics_plus1[ ][ ] is used in the inter-layer RPS syntax and semantics in a suboptimal way, because:The syntax elements of inter-layer RPS are included in the slice header even if TemporalId is such that inter-layer prediction is disallowed according to the max_tid_il_ref_pics_plus1[ ][ ] values.The length of the syntax elements num_inter_layer_ref_pics_minus1 and inter_layer_pred_layer_idc[i] is determined on the basis of NumDirectRefLayers [nuh_layer_id]. However, a smaller length could potentially be determined if max_tid_il_ref_pics_plus1[ ][ ] and the TemporalId of the current picture were taken into account, and accordingly inter_layer_pred_layer_idc[i] could be an index among those reference layers that can be used as reference for inter-layer prediction for the present TemporalId. To have correct operation when only the IRAP pictures of the reference layer may be used as reference for inter-layer prediction, the pseudo-code to specify a list identifying candidate inter-layer reference pictures refLayerPicIdc[ ] may be specified as follows: for( i = 0, j = 0; i < NumDirectRefLayers[ nuh_layer_id ]; i++ ) {refLayerIdx = LayerIdxInVps[ RefLayerId[ nuh_layer_id ][ i ] ]if( sub_layers_vps_max_minus1[ refLayerIdx ] >= TemporalId &&( max_tid_il_ref_pics_plus1[ refLayerIdx ][ LayerIdxInVps[ nuh_layer_id ] ] > TemporalId|| TemporalId = = 0 ) )refLayerPicIdc[ j++ ] = i}numRefLayerPics = j As mentioned, the presently described embodiment may be applied together with other embodiments. The presently described embodiment may be applied with an embodiment in which the encoder may encode and/or the decoder may decode e.g. into/from a sequence-level syntax structure, such as VPS, an indication whether TemporalId values or alike are aligned for coded pictures within an access unit as described in the following. To have correct operation when only the IRAP pictures of the reference layer may be used as reference for inter-layer prediction, the pseudo-code to specify a list identifying candidate inter-layer reference pictures refLayerPicIdc[ ] may be specified as follows: for( i = 0, j = 0; i < NumDirectRefLayers[ nuh_layer_id ]; i++ ) {refLayerIdx = LayerIdxInVps[ RefLayerId[ nuh_layer_id ][ i ] ]if( sub_layers_vps_max_minus1[ refLayerIdx ] >= TemporalId &&( max_tid_il_ref_pics_plus1[ refLayerIdx ][ LayerIdxInVps[ nuh_layer_id ] ] > TemporalId|| TemporalId = = 0 || !tid_aligned_flag ) )refLayerPicIdc[ j++ ] = i}numRefLayerPics = j Alternatively, when also utilizing max_tid_il_ref_pics_plus1[ ][ ] more optimally. the embodiment may be realized as described in the following paragraphs. The encoder may encode or the decoder may decode the inter-layer RPS related syntax elements with fixed-length coding, e.g. u(v), where the syntax element lengths may be selected according to the number of potential reference layers enabled by the nuh_layer_id value and the TemporalId value of the current picture being encoded or decoded. The syntax element values may indicate reference pictures among the potential reference layers enabled by the nuh_layer_id value and the TemporalId value. The potential reference layers may be indicated in a sequence-level syntax structure, such as VPS. The direct reference layers of each layer may be indicated separately from the sub-layers that may be used as reference for inter-layer prediction. For example, in MV-HEVC, SHVC and/or alike, the syntax elements direct_dependency_flag[i][j] may be used to indicate potential reference layers and the syntax elements max_tid_il_ref_pics_plus1[i][j] may be used to indicate whether inter-layer prediction may take place only from IRAP pictures and if that is not the case, the maximum sub-layer from which inter-layer prediction may take place. In the context of MV-HEVC, SHVC and/or alike, the variables NumDirectRefLayersForTid[lId][tId] and RefLayerIdListForTid[lId][tId][k] are derived based on VPS extension information. NumDirectRefLayersForTid[lId][tId] indicates the number of direct reference layers which may be used for inter-layer prediction of a picture with nuh_layer_id equal to lId and TemporalId equal to tId. RefLayerIdListForTid[lId][tId][k] is a list of nuh_layer_id values of direct reference layers which may be used for inter-layer prediction of a picture with nuh_layer_id equal to lId and TemporalId equal to tId. For example, the following pseudo-code may be used to derive NumDirectRefLayersForTid[lId][tId] and RefLayerIdListForTid[lId][tId][k], where MaxLayersMinus1 is the number of layers specified in the VPS minus 1 and LayerIdxInVps[layerId] specifies the index of the layer (in the range of 0 to MaxLayersMinus1, inclusive) within some structures and loops specified in the VPS. for( lIdx = 0; lIdx <= MaxLayersMinus1; lIdx++ ) {lId = layer_id_in_nuh[ lIdx ]for( tId = 0; tId < 7; tId++ ) {for( rCnt = 0, k = 0; rCnt < NumDirectRefLayers[ lId ];rCnt++ ) {refLayerIdx =LayerIdxInVps[ RefLayerId[ lId ][ rCnt ] ]if( sub_layers_vps_max_minus1[ refLayerIdx ] >=tId &&( max_tid_il_ref_pics_plus1[ refLayerIdx ][ lIdx ] > tId || tId = = 0 ) )RefLayerIdListForTid[ lId ][ tId ][ k++ ] =RefLayerId[ lId ][ rCnt ]}NumDirectRefLayersForTid[ lId ][ tId ] = k}} As mentioned, the presently described embodiment may be applied together with other embodiments. The presently described embodiment may be applied with an embodiment in which the encoder may encode and/or the decoder may decode e.g. into/from a sequence-level syntax structure, such as VPS, an indication whether TemporalId values or alike are aligned for coded pictures within an access unit as described in the following. To have correct operation when only the TRAP pictures of the reference layer may be used as reference for inter-layer prediction, the pseudo-code to derive NumDirectRefLayersForTid[lId][tId] and RefLayerIdListForTid[lId][tId][k] may be specified as follows: for( lIdx = 0; lIdx <= MaxLayersMinus1; lIdx++ ) {lId = layer_id_in_nuh[ lIdx ]for( tId = 0; tId < 7; tId++ ) {for( rCnt = 0, k = 0; rCnt < NumDirectRefLayers[ lId ];rCnt++ ) {refLayerIdx =rLayerIdxInVps[ RefLayerId[ lId ][ rCnt ] ]if( sub_layers_vps_max_minus1[ refLayerIdx ] >=tId &&( max_tid_il_ref_pics_plus1[ refLayerIdx ][ lIdx ] > tId || tId = = 0 || !tid_aligned_flag ) )RefLayerIdListForTid[ lId ][ tId ][ k++ ] =RefLayerId[ lId ][ rCnt ]}NumDirectRefLayersForTid[ lId ][ tId ] = k}} NumDirectRefLayersForTid[nuh_layer_id][TemporalId] is used instead NumDirectRefLayers[nuh_layer_id] in the inter-layer RPS syntax and semantics. Moreover, inter_layer_pred_layer_idc[i] is an index k to RefLayerIdListForTid[nuh_layer_id][TemporalId][k] (rather than an index k to RefLayerId[nuh_layer_id][k]). As a consequence, the syntax elements of inter-layer RPS are included in the slice header only if TemporalId is such that inter-layer prediction is disallowed according to the max_tid_il_ref_pics_plus1[ ][ ] values. Moreover, the length of the syntax elements num_inter_layer_ref_pics_minus1 and inter_layer_pred_layer_idc[i] is determined on the basis of NumDirectRefLayersForTid[nuh_layer_id][TemporalId] and hence may be shorter than if the lengths were determined on the basis of NumDirectRefLayers[nuh_layer_id]. For example, the following syntax may be used in the slice segment header syntax structure: if( nuh_layer_id > 0 && !all_ref_layers_active_flag &&NumDirectRefLayersForTid[ nuh_layer_id ][ TemporalId] > 0 ) {inter_layer_pred_enabled_flagu(1)if( inter_layer_pred_enabled_flag &&NumDirectRefLayersForTid[ nuh_layer_id ][TemporalId ] > 1) {if( !max_one_active_ref_layer_flag )num_inter_layer_ref_pics_minus1u(v)if( NumActiveRefLayerPics !=NumDirectRefLayersForTid[ nuh_layer_id ][ TemporalId] )for( i = 0; i < NumActiveRefLayerPics; i++ )inter_layer_pred_layer_idc[ i ]u(v)}} The semantics of the above except of the slice segment header syntax structure may be specified as described in the following paragraphs. num_inter_layer_ref_pics_minus1 plus 1 specifies the number of pictures that may be used in decoding of the current picture for inter-layer prediction. The length of the num_inter_layer_ref_pics_minus1 syntax element is Ceil(Log 2(NumDirectRefLayersForTid[nuh_layer_id][TemporalId])) bits. The value of num_inter_layer_ref_pics_minus1 shall be in the range of 0 to NumDirectRefLayersForTid[nuh_layer_id][TemporalId]−1, inclusive. The variable NumActiveRefLayerPics may be derived as follows: if( nuh_layer_id = = 0 ||NumDirectRefLayersForTid[ nuh_layer_id ][ TemporalId ] = = 0 )NumActiveRefLayerPics = 0else if( all_ref_layers_active_flag )NumActiveRefLayerPics = numRefLayerPicselse if( !inter_layer_pred_enabled_flag )NumActiveRefLayerPics = 0else if( max_one_active_ref_layer_flag ||NumDirectRefLayersForTid[ nuh_layer_id ][ TemporalId ] = = 1 )NumActiveRefLayerPics = 1elseNumActiveRefLayerPics = num_inter_layer_ref_pics_minus1 + 1 inter_layer_pred_layer_idc[i] specifies the variable, RefPicLayerId[i], representing the nuh_layer_id of the i-th picture that may be used by the current picture for inter-layer prediction. The length of the syntax element inter_layer_pred_layer_idc[i] is Ceil(Log 2(NumDirectRefLayersForTid[nuh_layer_id][TemporalId])) bits. The value of inter_layer_pred_layer_idc[i] shall be in the range of 0 to NumDirectRefLayersForTid[nuh_layer_id][TemporalId]−1, inclusive. When not present, the value of inter_layer_pred_layer_idc[i] is inferred to be equal to refLayerPicIdc[i]. The variables RefPicLayerId[i] for all values of i in the range of 0 to NumActiveRefLayerPics−1, inclusive, may be derived as follows: for( i = 0, j = 0; i < NumActiveRefLayerPics; i++)RefPicLayerId[ i ] = RefLayerIdListForTid[ nuh_layer_id ][ TemporalId ][ inter_layer_pred_layer_idc[ i ] ] In the case of hybrid codec scalability, a decoded picture of an external base layer may be provided for encoding and/or decoding of the enhancement layers, e.g. to serve as a reference for inter-layer prediction. In some embodiments, it may be required, for example in a coding standard, that the TemporalId values of the coded pictures in an access unit are the same, and the TemporalId value of the external base layer picture may be inferred to be equal to the TemporalId value of the pictures of the access unit which the external base layer picture is associated with. In some embodiments, it may be indicated, for example using the tid_aligned_flag or alike, whether the TemporalId values of the coded pictures in an access unit are required to be the same. When tid_aligned_flag or alike indicates that the TemporalId values of the coded pictures in an access unit are the same, the TemporalId value of the external base layer picture is inferred to be equal to the TemporalId value of the pictures of the access unit which the external base layer picture is associated with. Otherwise, the TemporalId value of the external base layer picture might not have an impact in the encoding or decoding of the pictures in the access unit which the external base layer is associated with and hence a TemporalId value for the external base layer picture needs not be derived. In some embodiments, the TemporalId value of the external base layer picture may be inferred to be equal to the TemporalId value of a selected picture in the access unit which the external base layer picture is associated with. The selected picture may be selected according to constraints and/or an algorithm, which may be specified for example in a coding standard. For example, the selected picture may be a picture for which the external base layer picture is a direct reference picture. If there are multiple pictures for which the external base layer picture is a direct reference picture, for example the one having the smallest nuh_layer_id value may be selected. There may be additional constraints on the TemporalId values of the pictures for an access unit which has an associated external base layer picture. For example, it may be required, e.g. by a coding standard, that the TemporalId values of each picture which use or may use the external base layer as an inter-layer reference picture has to be the same. Consequently, the TemporalId value of the external base layer picture may be derived from any picture for which the external base layer picture is a direct reference picture. A decoding method, which is disclosed inFIG.12, utilizes a bitstream encoded according to any of the embodiments described above. As shown inFIG.12, coded pictures of a first scalability layer are received (1200) and decoded (1202). Coded pictures of a second scalability layer are received (1204), wherein the second scalability layer depends on the first scalability layer. Then a layer access picture on the second scalability layer is selected (1206) from the coded pictures of a second scalability layer, wherein the selected layer access picture is a step-wise temporal sub-layer access picture on a lowest temporal sub-layer. Coded pictures on a second scalability layer prior to, in decoding order, the selected layer access picture are ignored (1208), and the selected layer access picture is decoded (1210). In an embodiment, the method ofFIG.13may be appended in subsequent steps to those presented inFIG.13as follows. The number of sub-layers the decoding of which is enabled by the selected layer access picture may be concluded. Then, pictures following, in decoding order, the selected layer access picture on those sub-layers whose decoding is enabled are sent, whereas pictures following, in decoding order, the selected layer access picture on those sub-layers whose decoding is not enabled are ignored until a suitable sub-layer access picture is reached. In addition to or instead of decoding, a bitstream encoded according to any of the embodiments described above may be utilized in bitrate adaptation by a sending apparatus (e.g. a streaming server) and/or by a gateway apparatus. In the bitrate adaptation method, which is shown inFIG.13, coded pictures of a first scalability layer are received (1300). Coded pictures of a second scalability layer are also received (1302), wherein the second scalability layer depends on the first scalability layer. A layer access picture on the second scalability layer is selected (1304) from the coded pictures of a second scalability layer, wherein the selected layer access picture is a step-wise temporal sub-layer access picture on the lowest temporal sub-layer. Coded pictures on a second scalability layer prior to, in decoding order, the selected layer access picture are ignored (1306), and the coded pictures of the first scalability layer and the selected layer access picture are sent (1308) in a bitstream. In an embodiment, the decoding method ofFIG.12may be appended in subsequent steps to those presented inFIG.12as follows. The number of sub-layers the decoding of which is enabled by the selected layer access picture may be concluded. Then, pictures following. in decoding order, the selected layer access picture on those sub-layers whose decoding is enabled are decoded, whereas pictures following, in decoding order, the selected layer access picture on those sub-layers whose decoding is not enabled are ignored until a suitable sub-layer access picture is reached. According to an embodiment. the layer access picture is the step-wise temporal sub-layer access picture, which depending on the use case, provides an access point either for layer-wise initialization of decoding of a bitstream with one or more temporal sub-layers or for layer-wise bitrate adaptation of a bitstream with one or more temporal sub-layers. The decoding process may be carried out as a joint sub-layer-wise and layer-wise start-up process for decoding presented. This decoding start-up process enables sub-layer-wise initialization of decoding of a bitstream with one or more layers. Thus, according to an embodiment, the method further comprises starting decoding of the bitstream in response to a base layer containing an IRAP picture or an STSA picture on the lowest sub-layer; starting step-wise decoding of at least one enhancement layer in response to said at least one enhancement layer contains IRAP pictures; and increasing progressively the number of decoded layers and/or the number of decoded temporal sub-layers. Herein, the layers may represent an enhancement along any scalability dimension or dimensions, such as those described earlier, e.g. an enhancement in spatial resolution, quality level, views, additional components such as depth, or a combination of any of above. According to an embodiment, the method further comprises generating unavailable pictures for reference pictures of a first picture in decoding order in a particular enhancement layer. According to an alternative embodiment, the method further comprises omitting the decoding of pictures preceding, in decoding order, the TRAP picture from which the decoding of a particular enhancement layer can be started. According to an embodiment, said omitted pictures may be labeled by one or more specific NAL unit types. These pictures, regardless of whether they are specifically marked with a NAL unit type or inferred e.g. by the decoder, may be referred to as cross-layer random access skip (CL-RAS) pictures. The decoder may omit the output of the generated unavailable pictures and/or the decoded CL-RAS pictures. According to an embodiment, the method further comprises maintaining information which sub-layers of each layer have been correctly decoded (i.e. have been initialized). For example, instead of LayerInitializedFlag[i] used in the layer-wise start-up process presented earlier, a variable HighestTidPlus1InitializedForLayer[i] may be maintained for each layer identifier i. HighestTidPlus1InitializedForLayer[i] equal to 0 may indicate that no pictures have been correctly decoded in layer with identifier i since the start-up mechanism was last started. HighestTidPlus1InitializedForLayer[i]−1 greater than or equal to 0 may indicate the highest TemporalId value that of the pictures that have been correctly decoded since the start-up mechanism was last started. A start-up process may be initiated similarly or identically to what was described earlier for the layer-wise start-up mechanism. When a layer-wise start-up mechanism is initiated, all pictures in the DPB may be marked as “unused for reference”. In other words, all pictures in all layers may be marked as “unused for reference” and will not be used as a reference for prediction for the picture initiating the layer-wise start-up mechanism or any subsequent picture in decoding order. A decoding process for a start-up may be for example controlled by two array variables HighestTidPlus1InitializedForLayer[i] and FirstPicInLayerDecodedFlag[i] which may have entries for each layer (possibly excluding the base layer and possibly other independent layers too). When the start-up process is invoked, for example as response to NoClrasOutputFlag being equal to 1, these array variables may be reset to their default values. For example, when there 64 layers are enabled (e.g. with a 6-bit nuh_layer_id). the variables may be reset as follows: the variable HighestTidPlus1InitializedForLayer[i] is set equal to 0 for all values of i from 0 to 63, inclusive, and the variable FirstPicInLayerDecodedFlag[i] is set equal to 0 for all values of i from 1 to 63, inclusive. The decoding process may include the following or similar to control the output of RASL pictures. When the current picture is an IRAP picture, the following applies:If HighestTidPlus1InitializedForLayer[nuh_layer_id] is equal to 0, the variable NoRas1OutputFlag is set equal to 1.Otherwise, if some external means is available to set the variable HandleCraAsBlaFlag to a value for the current picture, the variable HandleCraAsBlaFlag is set equal to the value provided by the external means and the variable NoRas1OutputFlag is set equal to HandleCraAsBlaFlag.Otherwise, the variable HandleCraAsBlaFlag is set equal to 0 and the variable NoRas1OutputFlag is set equal to 0. According to an embodiment, starting the step-wise decoding comprises one or more of the following conditional operations: when a current picture is an IRAP picture and decoding of all reference layers of the IRAP picture has been started, the IRAP picture and all pictures following it, in decoding order, in the same layer are decoded. when the current picture is an STSA picture at the lowest sub-layer and decoding of the lowest sub-layer of all reference layers of the STSA picture has been started, the STSA picture and all pictures at the lowest sub-layer following the STSA picture, in decoding order, in the same layer are decoded. when the current picture is a TSA or STSA picture at a higher sub-layer than the lowest sub-layer and decoding of the next lower sub-layer in the same layer has been started, and decoding of the same sub-layer of all the reference layers of the TSA or STSA picture has been started, the TSA or STSA picture and all pictures at the same sub-layer following the TSA or STSA picture, in decoding order. in the same layer are decoded. These conditional operations may be specified in more details for example as follows. The decoding process may include the following to update the HighestTidPlus1InitializedForLayer for a layer. When the current picture is an IRAP picture and either one of the following is true, HighestTidPlus1InitializedForLayer[nuh_layer_id] is set equal to a maximum TemporalId value plus 1 (where the maximum TemporalId value may be e.g. specified in the VPS or pre-defined in a coding standard).nuh_layer_id is equal to 0.HighestTidPlus1InitializedForLayer[nuh_layer_id] is equal to 0 and HighestTidPlus1InitializedForLayer[refLayerId] is equal to the maximum TemporalId value plus 1 for all values of refLayerId equal to RefLayerId[nuh_layer_id][j], where j is in the range of 0 to NumDirectRefLayers[nuh_layer_id]−1 , inclusive. When the current picture is an STSA picture with TemporalId equal to 0 and either one of the following is true, HighestTidPlus1InitializedForLayer[nuh_layer_id] is set equal to 1.nuh_layer_id is equal to 0.HighestTidPlus1InitializedForLayer[nuh_layer_id] is equal to 0 and HighestTidPlus1InitializedForLayer[refLayerId] is greater than 0 for all values of refLayerId equal to RefLayerId[nuh_layer_id][j], where j is in the range of 0 to NumDirectRefLayers[nuh_layer_id]−1, inclusive. When the current picture is a TSA picture or an STSA picture with TemporalId greater than 0 and both of the following are true, HighestTidPlus1InitializedForLayer[nuh_layer_id] is set equal to TemporalId+1.HighestTidPlus1InitializedForLayer[nuh_layer_id] is equal to TemporalId.HighestTidPlus1InitializedForLayer[refLayerId] is greater than or equal to TemporalId+1 for all values of refLayerId equal to RefLayerId[nuh_layer_id][j], where j is in the range of 0 to NumDirectRefLayers[nuh_layer_id]−1, inclusive. When FirstPicInLayerDecodedFlag[nuh_layer_id] is equal to 0, the decoding process for generating unavailable reference pictures may be invoked prior to decoding the current picture. The decoding process for generating unavailable reference pictures may generate pictures for each picture in a reference picture set with default values. The process of generating unavailable reference pictures may be primarily specified only for the specification of syntax constraints for CL-RAS pictures, where a CL-RAS picture may be defined as a picture with nuh_layer_id equal to layerId and LayerInitializedFlag[layerId] is equal to 0. In HRD operations, CL-RAS pictures may need to be taken into consideration in derivation of CPB arrival and removal times. Decoders may ignore any CL-RAS pictures, as these pictures are not specified for output and have no effect on the decoding process of any other pictures that are specified for output. A picture having such nuh_layer_id (or alike) and TemporalId (or alike) for which decoding has not yet been initialized may be handled by a decoder in a manner that it is not output by the decoder. Decoding of nuh_layer_id (or alike) with any TemporalId (or alike) value may be considered initialized when there is an TRAP picture with that nuh_layer_id value and the decoding of all the direct reference layers of the layer with that nuh_layer_id value have been initialized. Decoding of nuh_layer_id (or alike) and TemporalId (or alike) may be considered initialized when there is a TSA or STSA picture (or alike) with that nuh_layer_id value and that TemporalId value, and the decoding of all the direct reference layers of the layer with that nuh_layer_id value and that Temporal value have been initialized, and (when TemporalId is greater than 0) the decoding of the layer with that nuh_layer_id value and that TemporalId value minus 1 has been initialized. In the context of MV-HEVC, SHVC and/or alike. the controlling of the output of a picture may be specified as follows or in a similar manner. A picture with TemporalId equal to subLayerId and nuh_layer_id equal to layerId may be determined to be output (e.g. by setting PicOutputFlag equal to 1) by the decoder if HighestTidPlus1InitializedForLayer[layerId] is greater than subLayerId at the start of decoding the picture. Otherwise, the picture may be determined not to be output (e.g. by setting PicOutputFlag equal to 0) by the decoder. The determination of a picture to be output may further be affected by whether layerId is among the output layers of the target output layer set and/or whether a picture to be output is among alternative output layers if a picture at an associated output layer is not present or is not to be output. Cross-layer random access skipped (CL-RAS) pictures may be defined to be pictures with TemporalId equal to subLayerId and nuh_layer_id equal to layerId for which HighestTidPlus1InitializedForLayer[layerId] is greater than subLayerId at the start of decoding the picture. CL-RAS pictures may have the property that they are not output and may not be correctly decodable, as the CL-RAS picture may contain references to pictures that are not present in the bitstream. It may be specified that CL-RAS pictures are not used as reference pictures for the decoding process of non-CL-RAS pictures. According to an embodiment, a layer access picture may be encoded by an encoder to a bitstream that contains only one layer. For example, a layer access picture may be an STSA picture with nuh_layer_id equal to 0 and TemporalId equal to 0. According to an embodiment, the decoder may start decoding from a layer access picture at the lowest layer. For example, the decoder may start decoding from an STSA with nuh_layer_id equal to 0 and TemporalId equal to 0. The decoding may comprise a sub-layer-wise start-up, for example as described above. For example, the decoding may comprise maintaining information which sub-layers of each layer have been correctly decoded (i.e. have been initialized) and switching to the next available sub-layer or layer when a suitable layer access picture, sub-layer access picture, or TRAP picture is available in decoding order. The bitstream being decoded may comprise only one layer or it may comprise several layers. The utilization of the embodiments in bitrate adaptation is discussed in view of several examples. InFIG.14, it is assumed that the bitstream has been encoded as shown inFIG.8and that the sender performs bitrate adjustment by selecting adaptively the maximum TemporalId that is transmitted from the EL. For the first GOP, no EL pictures are transmitted. For the second GOP, the sender determines to increase the video bitrate and transmits as many EL sub-layers as possible. As there are STSA pictures available at TID 0, 1 and 2 (i.e. pictures 1. A and B, respectively), the sender switches up to transmit sub-layers with TID 0 to 2 starting from the second GOP of the EL. Switching up to TID 3 of the enhancement layer can take place later, when there is an EL IRAP picture or an EL TSA or STSA picture with TID equal to 3. It is noted that if the use of alternative output layers is enabled, pictures would be output constantly at “full” picture rate in this example. If the bitstream has been encoded such that at least one enhancement layer comprises more frequent TSA or STSA pictures than the base layer, for example as shown inFIG.9, the sender may dynamically adapt the bitrate of the transmission in a layer-wise manner by determining how many sub-layers are transmitted. Bitrate adjustment or bitrate adaptation may be used for example for providing so-called fast start-up in streaming services, where the bitrate of the transmitted stream is lower than the channel bitrate after starting or random-accessing the streaming in order to start playback immediately and to achieve a buffer occupancy level that tolerates occasional packet delays and/or retransmissions. Bitrate adjustment is also used when matching the transmitted stream bitrate with the prevailing channel throughput bitrate. In this use case it is possible to use a greater number of reference pictures in the base layer to achieve better rate-distortion performance. In the example ofFIG.15, it is assumed that the bitstream has been encoded as shown inFIG.9and that it has been necessary to reduce the bitrate of the first GOP when the bitstream is transmitted. In this example, only the pictures with TemporalId (TID) equal to 0 are transmitted for the first GOP. It is further assumed that the bitstream can be transmitted at its full bitrate starting from the second GOP. As the second GOP in EL starts with TSA pictures, it is possible to start transmitting EL pictures with all TID values. In the example ofFIG.16, it is assumed that the bitstream has been encoded such that non-aligned temporal sub-layer access pictures are encoded when only certain temporal levels are used for inter-layer prediction, as shown in the example ofFIG.10. It is further assumed that the sender is aware that the receiver uses an output layer set where only the enhancement layer is an output layer and hence the transmission of BL sub-layers that are not used as reference for inter-layer prediction is omitted. It is also assumed it has been necessary to reduce the bitrate of the first GOP when the bitstream is transmitted. In this example, the EL pictures with TemporalId in the range of 0 to 2, inclusive, are transmitted for the first GOP. It is further assumed that the bitstream can be transmitted at its full bitrate starting from the second GOP. As the second GOP in EL starts with TSA pictures, it is possible to start transmitting EL pictures with all TID values. In the example ofFIG.17, it is assumed that the bitstream has been encoded such that prediction hierarchies are determined differently across layers, as shown inFIG.11. It is further assumed that the sender adjusts the bitrate of the transmitted bitstream, whereupon the sender chooses to transmit only three sub-layers (TID 0, 1 and 2) of the EL. It is noted that if the use of alternative output layers is enabled, pictures would be output constantly at “full” picture rate in this example. FIG.18shows a block diagram of a video decoder suitable for employing embodiments of the invention.FIG.18depicts a structure of a two-layer decoder, but it would be appreciated that the decoding operations may similarly be employed in a single-layer decoder. The video decoder550comprises a first decoder section552for base view components and a second decoder section554for non-base view components. Block556illustrates a demultiplexer for delivering information regarding base view components to the first decoder section552and for delivering information regarding non-base view components to the second decoder section554. Reference P′n stands for a predicted representation of an image block. Reference D′n stands for a reconstructed prediction error signal. Blocks704,804illustrate preliminary reconstructed images (I′n). Reference R′n stands for a final reconstructed image. Blocks703,803illustrate inverse transform (T−1). Blocks702,802illustrate inverse quantization (Q−1). Blocks701,801illustrate entropy decoding (E−1). Blocks705,805illustrate a reference frame memory (RFM). Blocks706,806illustrate prediction (P) (either inter prediction or intra prediction). Blocks707,807illustrate filtering (F). Blocks708,808may be used to combine decoded prediction error information with predicted base view/non-base view components to obtain the preliminary reconstructed images (I′n). Preliminary reconstructed and filtered base view images may be output709from the first decoder section552and preliminary reconstructed and filtered base view images may be output809from the first decoder section554. FIG.20is a graphical representation of an example multimedia communication system within which various embodiments may be implemented. A data source1510provides a source signal in an analog, uncompressed digital, or compressed digital format, or any combination of these formats. An encoder1520may include or be connected with a pre-processing, such as data format conversion and/or filtering of the source signal. The encoder1520encodes the source signal into a coded media bitstream. It should be noted that a bitstream to be decoded may be received directly or indirectly from a remote device located within virtually any type of network. Additionally, the bitstream may be received from local hardware or software. The encoder1520may be capable of encoding more than one media type, such as audio and video, or more than one encoder1520may be required to code different media types of the source signal. The encoder1520may also get synthetically produced input, such as graphics and text, or it may be capable of producing coded bitstreams of synthetic media. In the following, only processing of one coded media bitstream of one media type is considered to simplify the description. It should be noted, however, that typically real-time broadcast services comprise several streams (typically at least one audio, video and text sub-titling stream). It should also be noted that the system may include many encoders, but in the figure only one encoder1520is represented to simplify the description without a lack of generality. It should be further understood that, although text and examples contained herein may specifically describe an encoding process, one skilled in the art would understand that the same concepts and principles also apply to the corresponding decoding process and vice versa. The coded media bitstream may be transferred to a storage1530. The storage1530may comprise any type of mass memory to store the coded media bitstream. The format of the coded media bitstream in the storage1530may be an elementary self-contained bitstream format, or one or more coded media bitstreams may be encapsulated into a container file. If one or more media bitstreams are encapsulated in a container file. a file generator (not shown in the figure) may be used to store the one more media bitstreams in the file and create file format metadata, which may also be stored in the file. The encoder1520or the storage1530may comprise the file generator, or the file generator is operationally attached to either the encoder1520or the storage1530. Some systems operate “live”, i.e. omit storage and transfer coded media bitstream from the encoder1520directly to the sender1540. The coded media bitstream may then be transferred to the sender1540, also referred to as the server, on a need basis. The format used in the transmission may be an elementary self-contained bitstream format, a packet stream format, or one or more coded media bitstreams may be encapsulated into a container file. The encoder1520, the storage1530, and the server1540may reside in the same physical device or they may be included in separate devices. The encoder1520and server1540may operate with live real-time content, in which case the coded media bitstream is typically not stored permanently, but rather buffered for small periods of time in the content encoder1520and/or in the server1540to smooth out variations in processing delay, transfer delay, and coded media bitrate. The server1540sends the coded media bitstream using a communication protocol stack. The stack may include but is not limited to one or more of Real-Time Transport Protocol (RTP), User Datagram Protocol (UDP), Hypertext Transfer Protocol (HTTP), Transmission Control Protocol (TCP), and Internet Protocol (IP). When the communication protocol stack is packet-oriented, the server1540encapsulates the coded media bitstream into packets. For example, when RTP is used, the server1540encapsulates the coded media bitstream into RTP packets according to an RTP payload format. Typically, each media type has a dedicated RTP payload format. It should be again noted that a system may contain more than one server1540, but for the sake of simplicity, the following description only considers one server1540. If the media content is encapsulated in a container file for the storage1530or for inputting the data to the sender1540, the sender1540may comprise or be operationally attached to a “sending file parser” (not shown in the figure). In particular, if the container file is not transmitted as such but at least one of the contained coded media bitstream is encapsulated for transport over a communication protocol. a sending file parser locates appropriate parts of the coded media bitstream to be conveyed over the communication protocol. The sending file parser may also help in creating the correct format for the communication protocol, such as packet headers and payloads. The multimedia container file may contain encapsulation instructions, such as hint tracks in the ISO Base Media File Format, for encapsulation of the at least one of the contained media bitstream on the communication protocol. The server540may or may not be connected to a gateway1550through a communication network. It is noted that the system may generally comprise any number gateways or alike, but for the sake of simplicity, the following description only considers one gateway1550. The gateway1550may perform different types of functions, such as translation of a packet stream according to one communication protocol stack to another communication protocol stack, merging and forking of data streams, and manipulation of data stream according to the downlink and/or receiver capabilities, such as controlling the bit rate of the forwarded stream according to prevailing downlink network conditions. Examples of gateways1550include multipoint conference control units (MCUs), gateways between circuit-switched and packet-switched video telephony, Push-to-talk over Cellular (PoC) servers, IP encapsulators in digital video broadcasting-handheld (DVB-H) systems, or set-top boxes or other devices that forward broadcast transmissions locally to home wireless networks. When RTP is used, the gateway1550may be called an RTP mixer or an RTP translator and may act as an endpoint of an RTP connection. The system includes one or more receivers1560, typically capable of receiving, de-modulating, and de-capsulating the transmitted signal into a coded media bitstream. The coded media bitstream may be transferred to a recording storage1570. The recording storage1570may comprise any type of mass memory to store the coded media bitstream. The recording storage1570may alternatively or additively comprise computation memory, such as random access memory. The format of the coded media bitstream in the recording storage1570may be an elementary self-contained bitstream format, or one or more coded media bitstreams may be encapsulated into a container file. If there are multiple coded media bitstreams, such as an audio stream and a video stream, associated with each other, a container file is typically used and the receiver1560comprises or is attached to a container file generator producing a container file from input streams. Some systems operate “live,” i.e. omit the recording storage1570and transfer coded media bitstream from the receiver1560directly to the decoder1580. In some systems, only the most recent part of the recorded stream, e.g., the most recent 10-minute excerption of the recorded stream, is maintained in the recording storage1570, while any earlier recorded data is discarded from the recording storage1570. The coded media bitstream may be transferred from the recording storage1570to the decoder1580. If there are many coded media bitstreams, such as an audio stream and a video stream, associated with each other and encapsulated into a container file or a single media bitstream is encapsulated in a container file e.g. for easier access, a file parser (not shown in the figure) is used to decapsulate each coded media bitstream from the container file. The recording storage1570or a decoder1580may comprise the file parser, or the file parser is attached to either recording storage1570or the decoder1580. It should also be noted that the system may include many decoders, but here only one decoder1570is discussed to simplify the description without a lack of generality The coded media bitstream may be processed further by a decoder1570, whose output is one or more uncompressed media streams. Finally, a renderer1590may reproduce the uncompressed media streams with a loudspeaker or a display. for example. The receiver1560, recording storage1570, decoder1570, and renderer1590may reside in the same physical device or they may be included in separate devices. A sender1540and/or a gateway1550may be configured to perform bitrate adaptation according to various described embodiments, and/or a sender1540and/or a gateway1550may be configured to select the transmitted layers and/or sub-layers of a scalable video bitstream according to various embodiments. Bitrate adaptation and/or the selection of the transmitted layers and/or sub-layers may take place for multiple reasons, such as to respond to requests of the receiver1560or prevailing conditions, such as throughput, of the network over which the bitstream is conveyed. A request from the receiver can be, e.g., a request for a change of transmitted scalability layers and/or sub-layers, or a change of a rendering device having different capabilities compared to the previous one. A decoder1580may be configured to perform bitrate adaptation according to various described embodiments, and/or a decoder1580may be configured to select the transmitted layers and/or sub-layers of a scalable video bitstream according to various embodiments. Bitrate adaptation and/or the selection of the transmitted layers and/or sub-layers may take place for multiple reasons, such as to achieve faster decoding operation. Faster decoding operation might be needed for example if the device including the decoder580is multi-tasking and uses computing resources for other purposes than decoding the scalable video bitstream. In another example, faster decoding operation might be needed when content is played back at a faster pace than the normal playback speed, e.g. twice or three times faster than conventional real-time playback rate. Available media file format standards include ISO base media file format (ISO/IEC 14496-12, which may be abbreviated ISOBMFF), MPEG-4 file format (ISO/IEC 14496-14, also known as the MP4 format), file format for NAL unit structured video (ISO/IEC 14496-15) and 3GPP file format (3GPP TS 26.244, also known as the 3GP format). The SVC and MVC file formats are specified as amendments to the AVC file format. The ISO file format is the base for derivation of all the above mentioned file formats (excluding the ISO file format itself). These file formats (including the ISO file format itself) are generally called the ISO family of file formats. The basic building block in the ISO base media file format is called a box. Each box has a header and a payload. The box header indicates the type of the box and the size of the box in terms of bytes. A box may enclose other boxes, and the ISO file format specifies which box types are allowed within a box of a certain type. Furthermore, the presence of some boxes may be mandatory in each file, while the presence of other boxes may be optional. Additionally, for some box types, it may be allowable to have more than one box present in a file. Thus, the ISO base media file format may be considered to specify a hierarchical structure of boxes. According to the ISO family of file formats, a file includes media data and metadata that are enclosed in separate boxes. In an example embodiment, the media data may be provided in a media data (mdat) box and the movie (moov) box may be used to enclose the metadata. In some cases, for a file to be operable, both of the mdat and moov boxes must be present. The movie (moov) box may include one or more tracks, and each track may reside in one corresponding track box. A track may be one of the following types: media, hint, timed metadata. A media track refers to samples formatted according to a media compression format (and its encapsulation to the ISO base media file format). A hint track refers to hint samples, containing cookbook instructions for constructing packets for transmission over an indicated communication protocol. The cookbook instructions may include guidance for packet header construction and include packet payload construction. In the packet payload construction, data residing in other tracks or items may be referenced. As such, for example, data residing in other tracks or items may be indicated by a reference as to which piece of data in a particular track or item is instructed to be copied into a packet during the packet construction process. A timed metadata track may refer to samples describing referred media and/or hint samples. For the presentation of one media type, typically one media track is selected. Samples of a track may be implicitly associated with sample numbers that are incremented by 1 in the indicated decoding order of samples. The first sample in a track may be associated with sample number 1. An example of a simplified file structure according to the ISO base media file format may be described as follows. The file may include the moov box and the mdat box and the moov box may include one or more tracks that correspond to video and audio, respectively. The ISO base media file format does not limit a presentation to be contained in one file. As such, a presentation may be comprised within several files. As an example, one file may include the metadata for the whole presentation and may thereby include all the media data to make the presentation self-contained. Other files, if used, may not be required to be formatted to ISO base media file format, and may be used to include media data, and may also include unused media data, or other information. The ISO base media file format concerns the structure of the presentation file only. The format of the media-data files may be constrained by the ISO base media file format or its derivative formats only in that the media-data in the media files is formatted as specified in the ISO base media file format or its derivative formats. The ability to refer to external files may be realized through data references. In some examples, a sample description box included in each track may provide a list of sample entries. each providing detailed information about the coding type used, and any initialization information needed for that coding. All samples of a chunk and all samples of a track fragment may use the same sample entry. A chunk may be defined as a contiguous set of samples for one track. The Data Reference (dref) box, also included in each track, may define an indexed list of uniform resource locators (URLs), uniform resource names (URNs), and/or self-references to the file containing the metadata. A sample entry may point to one index of the Data Reference box, thereby indicating the file containing the samples of the respective chunk or track fragment. Movie fragments may be used when recording content to ISO files in order to avoid losing data if a recording application crashes, runs out of memory space, or some other incident occurs. Without movie fragments, data loss may occur because the file format may typically require that all metadata, e.g., the movie box, be written in one contiguous area of the file. Furthermore, when recording a file, there may not be sufficient amount of memory space (e.g., RAM) to buffer a movie box for the size of the storage available, and re-computing the contents of a movie box when the movie is closed may be too slow. Moreover, movie fragments may enable simultaneous recording and playback of a file using a regular ISO file parser. Finally, a smaller duration of initial buffering may be required for progressive downloading, e.g., simultaneous reception and playback of a file, when movie fragments are used and the initial movie box is smaller compared to a file with the same media content but structured without movie fragments. The movie fragment feature may enable splitting the metadata that conventionally would reside in the movie box into multiple pieces. Each piece may correspond to a certain period of time for a track. In other words, the movie fragment feature may enable interleaving file metadata and media data. Consequently, the size of the movie box may be limited and the use cases mentioned above be realized. In some examples, the media samples for the movie fragments may reside in an mdat box, as usual, if they are in the same file as the moov box. For the metadata of the movie fragments, however, a moof box may be provided. The moof box may include the information for a certain duration of playback time that would previously have been in the moov box. The moov box may still represent a valid movie on its own, but in addition, it may include an mvex box indicating that movie fragments will follow in the same file. The movie fragments may extend the presentation that is associated to the moov box in time. Within the movie fragment there may be a set of track fragments, including anywhere from zero to a plurality per track. The track fragments may in turn include anywhere from zero to a plurality of track runs, each of which document is a contiguous run of samples for that track. Within these structures, many fields are optional and can be defaulted. The metadata that may be included in the moof box may be limited to a subset of the metadata that may be included in a moov box and may be coded differently in some cases. Details regarding the boxes that can be included in a moof box may be found from the ISO base media file format specification. A sample grouping in the ISO base media file format and its derivatives, such as the AVC file format and the SVC file format, may be defined as an assignment of each sample in a track to be a member of one sample group, based on a grouping criterion. A sample group in a sample grouping is not limited to being contiguous samples and may contain non-adjacent samples. As there may be more than one sample grouping for the samples in a track, each sample grouping has a type field to indicate the type of grouping. Sample groupings are represented by two linked data structures: (1) a SampleToGroup box (sbgp box) represents the assignment of samples to sample groups; and (2) a SampleGroupDescription box (sgpd box) contains a sample group entry for each sample group describing the properties of the group. There may be multiple instances of the SampleToGroup and SampleGroupDescription boxes based on different grouping criteria. These are distinguished by a type field used to indicate the type of grouping. The sample group boxes (SampleGroupDescription Box and SampleToGroup Box) reside within the sample table (stbl) box, which is enclosed in the media information (minf), media (mdia), and track (trak) boxes (in that order) within a movie (moov) box. The SampleToGroup box is allowed to reside in a movie fragment. Hence, sample grouping can be done fragment by fragment. In an embodiment, which may applied independently of or together with other embodiments, an encoder or another entity, such as a file creator, encodes or inserts an indication of one or more layer access pictures into a container file, which may for example conform to the ISO Base Media File Format and possibly some of its derivative file formats. A sample grouping for layer access pictures may for example be specified, or layer access picture may be indicated within another more generic sample grouping, e.g. for indication random access points. In some embodiments, a decoder or another entity, such as a media player or a file parser, decodes or fetches an indication of one or more layer access pictures into a container file, which may for example conform to the ISO Base Media File Format and possibly some of its derivative file formats. For example, the indication may be obtained from a sample grouping for layer access pictures, or from another more generic sample grouping, e.g. for indication random access points, which is also capable of indicating layer access pictures. The indication may be used to start decoding or other processing of the layer which the indication is associated with. It needs to be understood that an access unit for scalable video coding may be defined in various ways including but not limited to the definition of an access unit for HEVC as described earlier. Embodiments may be applied with different definitions of an access unit. For example, the access unit definition of HEVC may be relaxed so that an access unit is required to include coded pictures associated with the same output time and belonging to the same layer tree. When the bitstream has multiple layer trees, an access unit may but is not required to include coded pictures associated with the same output time and belonging to different layer trees. In the above, some embodiments have been described using MV-HEVC, SHVC and/or alike as examples, and consequently some terminology, variables, syntax elements, picture types, and so on specific to MV-HEVC, SHVC and/or alike have been used. It needs to be understood that embodiments could be realized with similar respective terminology, variables, syntax elements, picture types, and so on of other coding standards and/or methods. For example, in the above, some embodiments have been described with reference to nuh_layer_id and/or TemporalId. It needs to be understood that embodiments could be realized with any other indications, syntax elements, and/or variables for a layer identifier and/or a sub-layer identifier, respectively. In the above, some embodiments have been described with reference to a step-wise temporal sub-layer access picture on a lowest temporal sub-layer. It needs to be understood that embodiments could be realized similarly with any type of a layer access picture that provides correct decoding capability for a subset of pictures of the layers, such as for certain but not necessarily all sub-layers of a layer. In the above, some embodiments have been described in relation to encoding indications, syntax elements, and/or syntax structures into a bitstream or into a coded video sequence and/or decoding indications, syntax elements, and/or syntax structures from a bitstream or from a coded video sequence. It needs to be understood, however, that embodiments could be realized when encoding indications, syntax elements, and/or syntax structures into a syntax structure or a data unit that is external from a bitstream or a coded video sequence comprising video coding layer data, such as coded slices, and/or decoding indications, syntax elements, and/or syntax structures from a syntax structure or a data unit that is external from a bitstream or a coded video sequence comprising video coding layer data, such as coded slices. In the above, where the example embodiments have been described with reference to an encoder, it needs to be understood that the resulting bitstream and the decoder may have corresponding elements in them. Likewise, where the example embodiments have been described with reference to a decoder, it needs to be understood that the encoder may have structure and/or computer program for generating the bitstream to be decoded by the decoder. The embodiments of the invention described above describe the codec in terms of separate encoder and decoder apparatus in order to assist the understanding of the processes involved. However, it would be appreciated that the apparatus, structures and operations may be implemented as a single encoder-decoder apparatus/structure/operation. Furthermore, it is possible that the coder and decoder may share some or all common elements. Although the above examples describe embodiments of the invention operating within a codec within an electronic device, it would be appreciated that the invention as defined in the claims may be implemented as part of any video codec. Thus, for example, embodiments of the invention may be implemented in a video codec which may implement video coding over fixed or wired communication paths. Thus, user equipment may comprise a video codec such as those described in embodiments of the invention above. It shall be appreciated that the term user equipment is intended to cover any suitable type of wireless user equipment, such as mobile telephones, portable data processing devices or portable web browsers. Furthermore elements of a public land mobile network (PLMN) may also comprise video codecs as described above. In general, the various embodiments of the invention may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. The embodiments of this invention may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems. optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multi-core processor architecture, as non-limiting examples. Embodiments of the inventions may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate. Programs, such as those provided by Synopsys, Inc. of Mountain View, Calif and Cadence Design, of San Jose, Calif. automatically route conductors and locate components on a semiconductor chip using well established rules of design as well as libraries of pre-stored design modules. Once the design for a semiconductor circuit has been60completed, the resultant design, in a standardized electronic format (e.g., Opus, GDSII, or the like) may be transmitted to a semiconductor fabrication facility or “fab” for fabrication. The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention. | 254,152 |
RE49888 | DETAILED DESCRIPTION OF THE INVENTION The invention provides a new mechanism for mounting a magnetic head onto one of the walls or chassis of a magnetic card reader without using extended wings. The mechanism includes a frame for housing the magnetic head and an elastic or flexible elastic body at the back of the frame for applying the required pressure to the magnetic head. In one of the embodiments, the elastic body is in the form of a curved rectangular metal plate spring. The frame is made of metal and holds both the metal plate spring and the magnetic head compartment, as shown inFIG.2. The elastic body is coupled either flexibly or tightly to the frame. The whole mounting mechanism is mounted either flexibly or tightly to the wall or chassis of a card reader. With this mounting mechanism, the size of the whole magnetic head assembly is greatly reduced and it can be fit into a magnetic card reader with a more compact form factor. The mounting mechanism may also be used to mount a larger magneticreadreaderhead compartment than currently used in the traditional magnetic head assembly. The larger magneticreadreaderhead compartment is used to house additional electronic and mechanical components. A typical prior art magnetic card reader includes housing with a groove where a card with a magnetic stripe is slid along, and a magnetic reader head module mounted on one of the walls of the housing that form the groove or the chassis of the magnetic card reader. Referring toFIG.1, a typical prior art magnetic reader head module100includes a metal compartment101and a thin metal frame102. The metal compartment101houses the magnetic sensor frontend and the decoding circuitry. The thin metal frame102holds the metal compartment101and it includes a rectangular frame102and two sidewise extending wings103,104, for mounting the whole magnetic reader head module onto a wall or chassis of a magnetic card reader. The metal sheet of the frame102is flexible and allows the magnetic head sensor to retract away from the opposing wall when a card is slid across the groove. The wings103,104thus act as a spring and provide a pressure to keep the magnetic stripe and the magnetic head in close contact. The length of the wings103,104must be long enough for the spring to be effective. Therefore, the whole assembly occupies a lot of space in order to allow movement of the wings. The large size of the assembly is undesirable especially in cases where a small physical size is required. The present invention describes a method and the mechanism for mounting a magnetic reader head without using the extended wings103,104. Instead of the wings103,104, an elastic spring body is placed at the back209of the magnetic reader head in order to provide the required pressure for a good contact between the magnetic reader head and the magnetic stripe in the card to be read. Referring toFIG.2, the magnetic reader head module200of this invention includes a frame202, a metal plate spring220and the magnetic reader head201. Magnetic reader head201is placed within the frame202and metal plate spring220is placed behind the frame202, as shown inFIG.3AandFIG.3B. Metal plate spring220includes an elastic body222in the form of a thin, curved metal plate spring, as shown inFIG.5. The thin metal plate spring220is bent when a pressure is applied and a force that opposes the pressure applied is generated. Elastic body222of the metal plate spring220includes a central opening221and left and right side tabs223a and223b, respectively. Frame202includes a rectangular body210having a central opening208, left and right backward extending plates204a,204b, top and bottom frontward extending plates203a,203b, and top and bottom upward and downward extending plates205a,205b, respectively. Magnetic reader head compartment201is inserted into opening208and metal plate spring220isplaceplacedon the back side of the frame202within the space defined by the backward extending plates204a,204b. Metal plate spring220is secured onto the backside of the frame202by engaging the elastic body's222left and right side tabs223b,223a within slots207b,207a formed on the left and right side plates204b,204a of the frame202, respectively, as shown inFIGS.3A,3B and4. This loose coupling of the metal spring220with the frame202provides freedom of movement of the spring220. In one example, the magneticreadreaderhead compartment201is a metal case that is welded firmly to the frame202. Referring toFIG.6, frame201202holds the spring220and the magnetic read head compartment302201.FIG.7shows the displacement of the whole assembly when a card310is slid against thereadreaderhead302. The pressure from the card310pushes the whole module200back and the spring220flattens and extends sideways, as indicated by the dashed spring side profile220b, shown inFIG.7. Because of the elasticity of the spring220, module200is able to retract away from the card310and to apply a force that pushes thereadreaderhead302against the card310. This results in a good contact between the card310and thereadreaderhead302. By placing the elastic body220at the back of the frame201202instead of sideways, a lot of room can be saved. This allows a more flexible design of the magnetic card reader.FIG.8depictsFIGS. 8A and 8B depicta comparison of the top views of the prior art magneticreadreaderhead mounting mechanism100(bottom)(FIG. 8B)with the magneticreadreaderhead mounting mechanism of the present invention200(top)(FIG. 8A). As shown the magneticreadreaderhead mounting mechanism of the present invention200(top) is smaller than the magneticreadreaderhead mounting mechanism of the prior art100(bottom). FIG.9AshowsFIGS. 9A and 9B showa comparison of the top views of the prior art magneticreadreaderhead mounting mechanism100(bottom)(FIG. 9B)with another embodiment of a magneticreadreaderhead mounting mechanism of the present invention200(top)(FIG. 9A). In this embodiment, the size of the entire assembly is increased to take advantage of the additional space created by eliminating the side wings103,104. In this embodiment, a larger magneticreadreaderhead compartment201is used and this allows additional electronics or mechanical components to be housed inside the magneticreadreaderhead compartment201. Several embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims. | 6,560 |
RE49889 | The technology will next be described in connection with certain illustrated embodiments and practices. However, it will be clear to those skilled in the art that various modifications, additions, and subtractions can be made without departing from the spirit or scope of the claims. DETAILED DESCRIPTION OF THE TECHNOLOGY One or more embodiments of the technology provides, in a broad sense, systems and methods for providing digital advertisements to a consumer, then generating and/or modifying a shopping list for the consumer who selects one or more of the advertisements for viewing. A targeted advertisement may be presented to the consumer. The consumer selects the advertisement in a conventional manner such as clicking on, rolling over, or any other method of selecting an advertisement. After the advertisement is selected, or when the advertisement is selected the consumer may be provided with an option to place one or more of the advertised products or services into an electronic shopping list. Alternatively, one or more products may be automatically placed into the shopping list. The shopping list may then be configured to open when the consumer enters or comes within a defined proximity of an advertised store or enters or comes within a defined proximity of a store which carries the product or service or when the consumer manually selects to open the shopping list. The shopping list may be linked with a store map which provides the location of the product/service within the store and once the product/service is purchased, the product/service may automatically be removed from the list or it may need to be manually removed from the list. The following description is provided as an enabling teaching as it is best, currently known. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects described herein, while still obtaining the beneficial results of the technology disclosed. It will also be apparent that some of the desired benefits can be obtained by selecting some of the features while not utilizing others. Accordingly, those with ordinary skill in the art will recognize that many modifications and adaptations are possible, and may even be desirable in certain circumstances, and are a part of the technology described. Thus, the following description is provided as illustrative of the principles of the technology and not in limitation thereof. Discussion of an embodiment, one or more embodiments, an aspect, one or more aspects, a feature or one or more features is intended be inclusive of both the singular and the plural depending upon which provides the broadest scope without running afoul of the existing art and any such statement is in no way intended to be otherwise limiting in nature. Technology described in relation to one of these terms is not necessarily limited to use in that embodiment, aspect or feature and may be employed with other embodiments, aspects and/or features where appropriate. For purposes of this disclosure “mobile device” means a mobile phone, laptop computer, tablet computer, personal digital assistant (“PDA”), electronic reader (“e-reader”), mobile game console, smart watch, smart glasses, voice assistant devices, or any other mobile device which has the ability to run software applications (“apps”) and transmit and receive data. For purposes of this disclosure “remote” means accessible via network, telephone, email, text, video, website a combination of the same or any other form of communication wherein the parties need not be collocated to communicate. For purposes of this disclosure “targeted advertisement” or “targeted advertising” means one or more digital advertisement(s) directed to a consumer based on information known, learned or estimated about a consumer and/or directed to the consumer with information that could be used to identify the consumer. The advertisement need not be targeted to fall within a scope of the technology, but it is preferably. Thus, the terms “targeted advertisement” or “targeted advertising” may include random or semi-random advertisements. For purposes of this disclosure “item”, “product”, “service” are used interchangeably herein and means anything that can be sold or purchased in a brick and mortar store. For purposes of this disclosure “app” means a software application that can be run on a mobile device. It may also include a web accessible application. For purposes of this disclosure “Cloud”, “Web”, and/or “Internet” shall be used interchangeably herein and shall refer to the global wide area network referred to as the world wide web. For purposes of this disclosure “advertising creative” means pictures, banner ads, social ads, video ads or other conventional types of digital advertisements. In one or more embodiments, a consumer logs into an app on a mobile device. Initially, a consumer downloads the app and sets up a profile in which the consumer enters name, password and any other conventional information that is usually entered for signing up for an app. Once the consumer signs up for the app, the consumer may be presented with a login screen. The decision whether to require a login is a design choice. The consumer may sign up for the app prior to viewing a participating advertisement or may be provided the opportunity to sign up when viewing a participating advertisement. While logged in, a mobile advertisement may be displayed on the mobile device. Through an application programming interface (“API”), one or more mobile shopping lists may integrate technology directly into the app. The app may then be used on a consumer's mobile device. When the consumer selects the advertisement, the consumer may be presented with an option to save the advertised product into a shopping list. The list could be an existing list or a new list. The advertisement may be for a single item or it may be for multiple items. For advertisements which include multiple items the consumer may be provided a choice of which items to include in the shopping list. The list may be stored online (e.g. at a deep link URL), and/or at the mobile device (either directly or it may be pushed to the mobile device). The list may only include the item, or it may also include a store that sells the item. If the shopping list is for a specific store, the list may automatically open on the mobile device when the mobile device comes within a defined proximity to the store. This may be done via geo-fencing, beacon technology or some other location-based method. Optionally, the app may include a map of the store or a map of the store may be provided to the mobile device, which may show the location of the item(s) within the store. Upon checkout, the cashier may employ a merchant side app which sends information about the items purchased to the consumer side app so that items that were purchased may be automatically removed from the shopping list. In one or more embodiments, the consumer may be provided an option as to whether the item should be removed from the list or not. In one or more embodiments, as illustrated inFIG.1, a consumer10operates a mobile device20and an advertisement20may be displayed. If the consumer10does not select the advertisement45then the process ends45. If the consumer10selects the advertisement at50, an associated payload is served50to the mobile device20and the consumer10may be provided the option60to save the product60listed in the advertisement20. The consumer10may also be provided the option to open the app70(assuming the app is not already open). If the consumer does not open the app75the payload may be stored for a later time when the consumer10opens the app. If the consumer10opens the app at80it is determined if a deep link exists for the item60. If a deep link exists, then the item60is added to a shopping list100which may be displayed on the mobile device20. If a deep link does not exist, the app may retrieve a payload at90, process the payload at95and then the item60may be added to a shopping list100which may be displayed on the mobile device20. If the consumer10has already opened the app prior to viewing the advertisement, step70, determining if the user opened the app, may be skipped. As illustrated inFIG.2, the advertisement30may include multiple items60. The consumer10may be provided a choice of which items60to include in the shopping list100. When the consumer selects an item60or multiple items60to include, a payload may be created65for the selected item(s) and saved66. The consumer10may be provided the option to open the app70. If the consumer does not open the app75the payload may be stored for a later time when the consumer10opens the app. If the consumer10opens the app at80it is determined if a deep link exists for the item60. If a deep link exists, then the item60is added to a shopping list100which may be displayed on the mobile device20. If a deep link does not exist, the app will retrieve a payload at90, process the payload at95and then the item60may be added to a shopping list100which may be displayed on the mobile device20. If the consumer10has already opened the app prior to viewing the advertisement, step70, determining if the user opened the app may be skipped. In one or more embodiments, as illustrated inFIG.3, once the system is integrated and the app is running on a consumer's mobile device10, the API200communicates with a remote user database230and event database240. These may be separate databases or the same database. Unique identifiers may be transmitted to the user database230and actions taken within the app may be transmitted to the event database240. Once a user selects an advertisement30, a tracking payload may be saved to an online database230that maps tracking payloads to specific consumers. The consumer may then be routed to a landing page, which may open a deep link URL. This URL may attempt to open the consumer's mobile shopping list100. If the consumer chooses to skip this step, they may be presented with a close button or some other option. When a consumer opens their shopping list100, either via deep link or at a later time, the tracking payload may be retrieved from the remote database230. The client application sends a request to the database that contains a unique consumer identifier and an application identifier. The payload may then be passed from the database to the client application. Once the payload is received by the client application, it is decoded into the product data model. The client device then places information from the data model into the shopping list100. The shopping list may be an online list, and/or it may be pushed to the mobile device. As illustrated inFIG.4, through the web-based system, a product payload may be created which contains 1 or more products. The payload may include a custom data object that represents a specific product, including name, images, and universal product code (“UPC”) number and/or other custom identifiers, as well as internal identifiers. In addition, a payload may also contain metadata that will be used as content to be saved to a user's shopping list. Metadata may include product name, quantity, pictures of the product, and price. Additional information and/or different information may be included. Once metadata is saved, that data may be used to generate multiple payloads. Payloads may be created prior to being embedded within an advertisement. Creation of a payload may include a system administrator logging into a web-based application service400. The system admin may search410for one or more items to include in the payload. If the item does not already exist, then the admin may create a new item425. If the item exists in the system or after the admin creates the new item425the admin may select the item430. The admin then may update an ad creative440to create a payload440. The payload is then saved450. When generating payloads, a combination of products, apps, and advertising creatives may be combined. Payloads may then be preconfigured for specific execution channels, such as ad exchanges, social ad exchanges, or other mobile applications. Once a payload is combined with an execution channel, a series of unique URLs, which are not limited to standard HTTP environments, may be generated and saved to a cloud-based payload service. The unique URLs may then be used to enable any type of mobile advertisement to support Add-To-List functionality. In one or more embodiments, once a consumer interacts with an advertisement, they may be taken to the unique link generated with a payload. At that time, a tracking identifier and a user identifier may be saved to the payload service. A tracking payload may be created which contains tracking mechanisms for the product payload, combined with a specific mobile app. This tracking payload may be converted into a deep link URL, HTML Ad Tag, with one more encoding methods. The tracking payload may be added to a mobile advertisement. The advertisement may leverage any of the above methods. Through an interface, images are uploaded and converted into ad placements for use within ad exchanges/servers. When a consumer views an advertisement they may have the option to immediately open the application with the shopping list they use or move on from the advertisement and open the list later. When a user chooses to open the application immediately, an optional deep link URL may open the application and deliver the payload content directly to the app. Once the app is open, the API installed on the client device may collect the data from the payload and place the product on the shopping list. At this point, the payload identifier for the user identifier may be removed from the payload service. If the user chooses not to open the app, the payload may remain saved in the payload service with the user identifier collected. In one or more embodiments the API on the client device may communicate with the payload service and retrieve one or more payloads for the user identifier. The API may collect the data from the payload and place the product on the shopping list. At this point, the payload identifier for the user identifier may be removed from the payload service. FIG.5is a functional block diagram of a mobile device20illustrating various modules which provide list generation/modification and their interactions. Aside from the various modules illustrated inFIG.5, mobile device20may include one or more elements illustrated inFIG.6(e.g. processor610, memory620, storage630, input/output interface640, communication interface650, clock660and bus670) which may be employed to realize one or more of the various modules. As illustrated, mobile device20may include a mobile advertisement presentation module510, stored in memory, that provides a mobile advertisement which is associated with a product, for display on mobile device20. It may include an advertisement selection module520, stored in memory, that detects when an advertisement has been selected for viewing, a routing module530, stored in memory, that routes a browser located on the mobile device to a shopping list, a list generating module540, stored in memory, that enters information about the advertised product into the shopping lit, and at least one processor that executes the mobile advertisement presentation module, the advertisement selection module, the routing module, and the list generating module. Having thus described preferred embodiments of the technology, advantages can be appreciated. Variations from the described embodiments exist without departing from a scope of the invention. It is seen that systems and methods are provided for generating and/or modifying a shopping list from a selection of mobile advertisements. The advertisements may be targeted to a consumer or they may include information that associates the advertisement with the consumer or they may be random. Although specific embodiments have been disclosed herein in detail, this has been done for purposes of illustration only, and is not intended to be limiting with respect to the scope of the claims, which follow. In particular, it is contemplated by the inventors that various substitutions, alterations, and modifications may be made without departing from the spirit and scope of the technology as defined by the claims. Other aspects, advantages, and modifications are considered to be within the scope of the following claims. The claims presented are representative of the technology disclosed herein. Other, unclaimed technology is also contemplated. The inventors reserve the right to pursue such technology in later claims. Insofar as embodiments of the technology described above are implemented, at least in part, using a computer system, it will be appreciated that a computer program for implementing at least part of the described methods and/or the described systems is envisaged as an aspect of the technology. The computer system may be any suitable apparatus, system or device, electronic, optical, or a combination thereof. For example, the computer system may be a programmable data processing apparatus, a computer, a Digital Signal Processor, an optical computer or a microprocessor. The computer program may be embodied as source code and undergo compilation for implementation on a computer, or may be embodied as object code, for example. It is also conceivable that some or all of the functionality ascribed to the computer program or computer system aforementioned may be implemented in hardware, for example by one or more application specific integrated circuits and/or optical elements. Suitably, the computer program can be stored on a carrier medium in computer usable form, which is also envisaged as an aspect of the technology. For example, the carrier medium may be solid-state memory, optical or magneto-optical memory such as a readable and/or writable disk for example a compact disk (CD) or a digital versatile disk (DVD), or magnetic memory such as disk or tape, or mobile phone and the computer system can utilize the program to configure it for operation. The computer program may also be supplied from a remote source embodied in a carrier medium such as an electronic signal, including a radio frequency carrier wave or an optical carrier wave. It is accordingly intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative rather than in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the technology as described herein, and all statements of the scope of the technology which, as a matter of language, might be said to fall there between. | 18,851 |
RE49890 | Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. DETAILED DESCRIPTION The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents. It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. The present disclosure relates to a user device capable of displaying information related to a conversation, which is input into a messenger, as a background screen (e.g., a background screen of the conversation) of the messenger and a method for providing information in the user device. According to various embodiments of the present disclosure, text related to particular content may be detected from a conversation that a user exchanges with at least one other user through the messenger, various contents (e.g., information and an advertisement) related to the detected text may be provided in the form of a background in a conversation window. According to an embodiment of the present disclosure, the user device may analyze text of a conversation exchanged through the messenger, and may extract a content image related to the analyzed text. Then, the user device may display the extracted content image on the background of the messenger and may execute a function associated with the relevant content image in response to the user's selection to the content image displayed as the background, thereby providing useful information to the user. Hereinafter, a configuration of a user device according to various embodiments of the present disclsoure and an operation control method thereof will be described with reference to the accompanying drawings. The configuration of the user device according to the various embodiments of the present disclsoure and the operation control method thereof are not limited to or restricted by the various embodiments described below. Accordingly, it should be noted that the configuration of the user device and the operation control method thereof may be applied to various embodiments based on the following various embodiments. FIG.1is a block diagram schematically illustrating a configuration of a user device according to an embodiment of the present disclosure. Referring toFIG.1, the user device includes a wireless communication unit110, a user input unit120, a touch screen130, an audio processing unit140, a storage unit150, an interface unit160, a control unit170, and a power supply unit180. In an embodiment of the present disclsoure, a user device does not include the elements illustrated inFIG.1as essential ones. Accordingly, a user device may be implemented so as to include more elements than those illustrated inFIG.1, or may be implemented so as to include fewer elements than those illustrated inFIG.1. For example, when supporting an image capturing function, a user device according to an embodiment of the present disclsoure may further include a camera module. In contrast, when a user device according to an embodiment of the present disclsoure does not support a broadcast reception and reproduction function, a certain module (e.g., a broadcast receiving module119of the wireless communication unit110) may be omitted from the user device. The wireless communication unit110may include one or more modules which enable wireless communication between the user device and a wireless communication system or between the user device and another user device. For example, the wireless communication unit110may include a mobile communication module111, a Wireless Local Area Network (WLAN) module113, a short-range communication module115, a location calculation module117, a broadcast receiving module119, and the like. The mobile communication module111transmits and receives wireless signals to/from at least one of a base station, an external terminal, and various servers (e.g., an integration server, a provider server, a content server, an Internet server, a cloud server, etc.) through a mobile communication network. Examples of the wireless signal may include a voice call signal, a video call signal, and data in various forms according to the transmission and reception of text/multimedia messages. The mobile communication module111may transmit data (e.g., text, an emoticon, and a file such as an image, a moving image or the like) that the user has input into a messenger, or may receive data from the outside. Also, the mobile communication module111may be connected to a server matched to a content image displayed as a background of the messenger, and may receive relevant information. The WLAN module113enables the user device to connect to a wireless Internet, and forms a WLAN link between the user device and another user device. The WLAN module113may be mounted inside or outside the user device. Use may be made of Wireless Internet technologies, such as WLAN (Wi-Fi), Wireless broadband (Wibro), World Interoperability for Microwave Access (Wimax), High Speed Downlink Packet Access (HSDPA), and the like. The WLAN module113may transmit data that the user has input into the messenger, or may receive data from the outside. Also, the WLAN module113may be connected to a server matched to a content image displayed as the background of the messenger, and may receive relevant information. Further, when a WLAN link is formed between the user device and another user device, the WLAN module113may transmit various data (e.g., an image, a moving image, music, etc.) according to the user's selection to another user device, or may receive various data (e.g., an image, a moving image, music, etc.) according to another user's selection from another user device. The WLAN module113may maintain a normal on state, or may be turned on according to the user's setting or the user's input. The short-range communication module115is used for short-range communication. Use may be made of short-range communication technologies, such as Bluetooth, Bluetooth Low Energy (BLE), Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, Near Field Communication (NFC), and the like. When the user device is connected to another user device through short-range communication, the short-range communication module115may transmit various data (e.g., an image, a moving image, music, etc.) according to the user's selection to another user device, or may receive various data (e.g., an image, a moving image, music, etc.) according to another user's selection from another user device. The short-range communication module115may maintain a normal on state, or may be turned on according to the user's setting or the user's input. The location calculation module117is used to acquire a location of the user device, and may include a Global Positioning System (GPS) module in a typical example. The location calculation module117calculates information on a distance between the user device and each of three or more base stations and information on an accurate time point at which the distance information has been measured, applies trigonometry to the calculated distance information and time information, and thereby may calculate Three-Dimensional (3D) current location information according to latitude, longitude and altitude. Alternatively, the location calculation module117continuously receives, in real time, location information of the user device from each of three or more satellites, and thereby may calculate current location information. The location information of the user device may be acquired by using various methods. The broadcast receiving module119receives broadcast signals (e.g., a TV broadcast signal, a radio broadcast signal, a data broadcast signal, etc.) and/or broadcast-related information (e.g., information related to a broadcast channel, a broadcast program, a broadcast service provider or the like) from an external broadcast management server via a broadcast channel (e.g., a satellite broadcast channel, a terrestrial broadcast channel, etc.). The user input unit120may generate input data for controlling an operation of the user device, in response to a user input. The user input unit120may include a keypad, a dome switch, a touch pad (static pressure/capacitance), a jog wheel, a jog switch, a sensor (e.g., a voice recognition sensor, a proximity sensor, an illuminance sensor, an acceleration sensor, a gyro sensor, etc.), and the like. Also, the input unit120may be implemented in the form of buttons on an outer surface of the user device, and some buttons may be implemented by using a touch panel. The user input unit120may receive a user input for executing the messenger, and may generate an input signal according to the received user input. The user input unit120may receive a user input for inputting (i.e., attaching) various data (e.g., text, an emoticon, a file, etc.) matched to a conversation in the messenger, and may generate an input signal according to the received user input. Also, the user input unit120may receive a user input for selecting a content image displayed as a background in the messenger, and may generate an input signal according to the received user input. The touch screen130is an input means which simultaneously performs an input function and a display function, and may include a display unit131and a touch sensing unit133. For example, the touch screen130may display various screens (e.g., a screen according to the operation of the messenger, a screen for call origination, a game screen, a gallery screen, etc.) according to the operation of the user device through display unit131. When the touch sensing unit133receives an input corresponding to a touch event from the user while the display unit131displays a particular screen, the touch screen130may deliver an input signal according to the touch event, to the control unit170. Then, the control unit170may distinguish the touch event from another touch event, and may control the execution of an operation according to the touch event. According to an embodiment of the present disclosure, the touch screen130may receive a touch event for the input of text by the user while displaying a conversation screen according to the operation of the messenger, and may display the relevant text on the conversation screen of the messenger displayed through the display unit131, according to the control of the control unit170. Then, the touch screen130may display a content image related to content detected from the text as a background of the messenger according to the control of the control unit170, may receive a touch event for selection of the content image by the user while displaying the content image, and may display a screen executed in relation to the relevant content image according to the control of the control unit170. The display unit131may display (i.e., output) information processed by the user device. For example, when the user device is in a call mode, the display unit131displays a User Interface (UI) or a Graphical UI (GUI) related to a call. When the user device is in a video call mode or in an image capturing mode, the display unit131displays a captured and/or received image, a UI, or a GUI. For example, in an embodiment of the present disclsoure, the display unit131may display an execution screen of the messenger, and may display data received as input from the user and data received from the outside in the messenger, namely, data exchanged between users for a conversation, by using a set UI or GUI. Also, the display unit131may display a content image related to particular content detected from text as a background of the messenger while displaying an execution screen of the messenger, and may display an execution screen of a function (or an application) executed in relation to the content image. Further, the display unit131may support the display of screen switching depending on a change between the display of a screen in a landscape mode and that of a screen in a portrait mode, according to a rotation direction (or a placement direction) of the user device. Examples of a screen of the display unit131which are operated according to various embodiments of the present disclsoure will be described below. The display unit131may include at least one of a Liquid Crystal Display (LCD), a Thin Film Transistor-LCD (TFT LCD), a Light Emitting Diode (LED) display, an Organic LED (OLED) display, an Active Matrix OLED (AMOLED) display, a flexible display, a bended display, a 3D display, and the like. Some of these displays may be transparent displays implemented so as to be transparent or light-transparent in order to enable the user to see the outside through the display. The touch sensing unit133may be placed on the display unit131, and may sense a touch event by the user which contacts the surface of the touch screen130. Examples of the touch event may include a tap, a drag, a sweep, a flick, a drag and drop, a drawing, a single touch, a multi-touch, a gesture (e.g., writing, etc.), and hovering. When sensing a touch event by the user on the surface of the touch screen130, the touch sensing unit133may detect coordinates at which the touch event has been generated, and may deliver the detected coordinates to the control unit170. For example, the touch sensing unit133may sense the touch event generated by the user, may generate a signal according to the sensed touch event, and may deliver the generated signal to the control unit170. The control unit170may perform a function corresponding to an area, in which the touch event has been generated, in response to the signal delivered by the touch sensing unit133. The touch sensing unit133may receive, as input, a touch event for executing the messenger, and may generate an input signal according to the received touch event. The touch sensing unit133may receive, as input, a touch event for inputting (i.e., attaching) various data (e.g., text, an emoticon, a file, etc.) matched to a conversation in the messenger, and may generate an input signal according to the received touch event. Also, the touch sensing unit133may receive, as input, a touch event for selecting a content image displayed as a background in the messenger, and may generate an input signal according to the received touch event. The touch sensing unit133may be configured to convert a pressure applied to a particular part of the display unit131or a change in capacitance generated at the particular part thereof, into an electrical input signal. The touch sensing unit133may be configured to be capable of detecting not only a touched position and a touched area but also even a pressure during a touch according to an applied touch scheme. When a touch input is provided to the touch sensing unit133, a signal (or signals) matched to the touch input may be delivered to a touch controller (not illustrated). The touch controller may process the signal (or signals), and may deliver relevant data to the control unit170. Accordingly, the control unit170may determine which area of the touch screen130has been touched. The audio processing unit140may deliver an audio signal, which has been received as input from the control unit170, to a Speaker (SPK)141, and may deliver an audio signal such as a voice and the like, which has been received as input from a Microphone (MIC)143, to the control unit170. According to the control of the control unit170, the audio processing unit140may convert voice/sound data into an audible sound and may output the audible sound, through the SPK141. The audio processing unit140may convert an audio signal, such as a voice and the like, which has been received from the MIC143, into a digital signal, and may deliver the digital signal to the control unit170. The SPK141may output audio data, which has been received from the wireless communication unit110or is stored in the storage unit150, in a messenger mode, a call mode, a message mode, an audio (or video) recording mode, a voice recognition mode, a broadcast reception mode, a media content (e.g., a music file and a moving image file) reproduction mode, and the like. The SPK141may output a sound signal related to a function performed by the user device. Examples of the function may include messenger execution, conversation reception, conversation transmission, content image display, the execution of a content image-related function, the reception of a call connection, the transmission of a call connection, image capturing, the reproduction of a media content file, and the like. The MIC143may receive, as input, an external sound signal and may process the external sound signal into an electrical voice data, in the messenger mode, the call mode, the message mode, the audio (or video) recording mode, the voice recognition mode, and the like. In the call mode, the processed voice data may be converted into a form transmissible to a mobile communication base station through the mobile communication module111, and the voice data in the form transmissible to the mobile communication base station may be output. Various noise removal algorithms may be implemented in the MIC143in order to remove noise generated in process of receiving the external sound signal as input. The storage unit150may store programs for processing and control performed by the control unit170, or may temporarily store input/output data. Examples of the input/output data may include messenger data (i.e., conversation data), a content image, contact information, a message, media content (e.g., audio, a moving image, and an image), and the like. The storage unit150may store the frequency of use, the level of importance, and priority according to the operation of a function of the user device, together. Examples of the frequency of use may include the frequency of use of an application, the frequency of use of an attribute for each application, the frequency of use of content, and the like. The storage unit150may store data on vibrations and sounds of various patterns, which are output in response to a touch input on the touch screen130. For example, in an embodiment of the present disclosure, the storage unit150may store text matched to content, a content image matched to content, a function matched to content (or a content image), and the like. Here, data such as text, a content image, a function, or the like, which is matched to content, may be generated during execution of an application such as a messenger and the like, or may be periodically received or updated from or by a server through a wired and/or wireless communication network. The server may be managed by an advertiser, a communication service provider, a manufacturer, or the like that is related to content. The server may store data such as text, a content image, a function, or the like, which is matched to content, and may manage the data by updating the data periodically or whenever an event is generated. In various embodiments of the present disclosure, examples of content may include multimedia content, digital content, Internet content, and the like in various industrial fields, which can be transmitted through a wired and/or wireless communication network. Here, examples of the various industrial fields may include recording, games, sightseeing (travel), movies, broadcasting, animation, publishing, food, and the like. For example, in various embodiments of the present disclsoure, examples of the content may include recording content, movie content, broadcast content, sightseeing (travel) content, food content, game content, animation content, and the like. According to an embodiment of the present disclsoure, when the user inputs text reading “Let's take a trip.” into the messenger, the user device may sense the text, and may detect a word (i.e., “trip”) related to “sightseeing (travel) content.” In other words, according to various embodiments of the present disclsoure, the user device may detect text related to content (e.g., sightseeing (travel) content, broadcast content, movie content, food content, etc.) from a conversation exchanged through the messenger. Also, the user device may internally extract a content image related to the detected text (or content), or may acquire (e.g., download) the relevant content image from a relevant server. Here, the content image, for example, may be a content image having link information connected to a particular site (i.e., server) related to sightseeing (travel), and the like. Then, the user device may display the relevant content image as a background of the messenger. The storage unit150may continuously or temporarily store an Operating System (OS) of the user device, a program related to an operation for controlling input and display using the touch screen130, a program related to an operation for controlling the transmission/reception of data by the messenger, a program related to an operation for controlling the display of a content image as a background in the messenger, a program related to a function control operation performed in cooperation with a content image, data generated by an operation of each program, and the like. The storage unit150may include a storage medium of at least one type from among a flash memory type, a hard disk type, a multimedia card micro type, a memory card type (e.g., a Secure Digital (SD) or eXtreme Digital (XD) memory card), a Dynamic Random Access Memory (DRAM), a Static RAM (SRAM), a Read Only Memory (ROM), a Programmable ROM (PROM), an Electrically Erasable PROM (EEPROM), a Magnetic RAM (MRAM), a magnetic disk, an optical disk, and the like. The user device may also operate in relation to a web storage which performs a storage function of the storage unit150on the Internet. The interface unit160may serve as a passage to all external devices connected to the user device. The interface unit160may receive data transmitted by an external device, may be supplied with power and may deliver the power to each element within the user device, or may allow data within the user device to be transmitted to an external device. For example, the interface unit160may include a wired/wireless headset port, an external charger port, a wired/wireless data port, a memory card port, a port for connecting the user device to a device including an identity module, an audio Input/Output (I/O) port, a video I/O port, an earphone port, and the like. The control unit170may control an overall operation of the user device. For example, the control unit170may perform control related to voice communication, data communication, video communication, and the like. The control unit170may process an operation related to a function of displaying information related to text, which is received as input inside or outside the messenger, on a background screen of the messenger, or may include a data processing module (not illustrated) which processes the operation related to the function. According to various embodiments of the present disclosure, the control unit170may execute the messenger in response to a user input, and may display a conversation (particularly, text), which the user exchanges with at least one another user through the messenger, so as to be overlaid on the background of the messenger. The control unit170may sense the conversation (particularly, text) exchanged through the messenger, and may detect text (e.g., characters, a word, a word sequence, etc.) matched to particular content, from the exchanged text. Examples of a scheme in which the control unit170detects the particular content from the conversation may include a scheme for storing the corresponding text in the form of a mapping table, a semantic analysis scheme, an ontology scheme, and the like. In the scheme for storing the corresponding text in the form of a mapping table, when the corresponding text matched to the particular content is stored in the form of a mapping table, if the control unit170searches the conversation for the corresponding text and text which coincides with or is similar to the corresponding text is included in the conversation, the control unit170may determine that the particular content is detected. In the semantic analysis scheme or the ontology scheme, the control unit170extracts meaning from the conversation (or text), and analyzes a correlation between a concept corresponding to the extracted meaning and a concept matched to content. When the correlation has a value greater than or equal to a predetermined value, the control unit170may determine that the particular content is detected. Also, in the semantic analysis scheme or the ontology scheme, the user device may include data, a drive engine, and the like for implementing the relevant algorithm, or a server may include at least a part of modules such as the data, the drive engine and the like. According to an embodiment of the present disclsoure, the user device may transmit the conversation (or text) to the server, and may receive information as to whether the particular content has been detected, from the server. Alternatively, a step of transmitting the conversation from the user device to the server may be omitted. For example, a service server which provides a messenger service may determine whether the particular content has been detected, or a separate server which receives the conversation from the service server may determine whether the particular content has been detected. Alternatively, use may be made of a hybrid scheme in which a content detection process is divided into sub-processes and the user device and the server perform the sub-processes. In addition, it should be noted that various schemes other than the above-described detection schemes may be used and schemes including the above-described detection schemes may be modified and used or may be used in a combination thereof. The control unit170may acquire a content image related to content of the detected text, and may display the acquired content image as a background of the messenger. When displaying the acquired content image as the background of the messenger, the control unit170does not replace a background (hereinafter referred to as an “original background”) which is basically set for the messenger, but may overlay the content image on the original background and may provide the content image overlaid on the original background. In the present example, because a main function of the messenger is intended to provide in real time a conversation between the users, it is required to maintain the visibility of a speech bubble including an identifier (e.g., an icon, an image, etc.) indicating the contents of the conversation exchanged between the users and a subject of the conversation. Accordingly, when displaying the content image as the background, the control unit170may perform a control operation for displaying the content image in between the original background and a speech bubble. According to an embodiment of the present disclsoure, a content image may be provided in such a manner as to generate a new layer between a layer in which the original background is provided and another layer in which a speech bubble is provided. Also, according to various embodiments of the present disclosure, a user input may be supported for each of the original background, a content image and a speech bubble. The control unit170may execute a function related to the content image in response to a user input related to the content image in a state of displaying the content image, and may operate so as to display a related screen according to the execution of the function. When the content image is selected, the control unit170may analyze the type (e.g., information providing type) of the relevant content (or content image), and may operate so as to execute a function matched to the analyzed type (e.g., information providing type). The control unit170may perform a control operation for providing related information of the content through the executed function. Also, when displaying the content image, the control unit170may count a time period for displaying the content image. When a set time period elapses, the control unit170may operate so as to remove the displayed content image. In a state of displaying the content image or in a state where no content image is displayed, the control unit170may extract a content image related to content of text selected in response to a user input related to the text of a previous conversation, and may operate so as to display the extracted content image. At this time, when there exists a content image currently being displayed, the control unit170may replace the currently-displayed content image by the extracted content image, and may display the replaced content image. Control operations of the control unit170will be described together with operations of the user device and a control method thereof with reference to the accompanying drawings. The control unit170may control various operations related to typical functions of the user device as well as the above-described functions. For example, when a particular application is executed, the control unit170may control the operation and screen display of the particular application. Also, the control unit170may receive input signals corresponding to the input of various touch events supported by a touch-based input interface (e.g., the touch screen130), and may control the operation of functions according to the received input signals. Further, the control unit170may control the transmission and reception of various data, which are based on wired communication or wireless communication. Under the control of the control unit170, the power supply unit180may be supplied power from an external power source or an internal power source, and may provide power required for an operation of each element within the user device. In various embodiments of the present disclsoure as described above, examples of the user device may include all types of devices, which use an Application Processor (AP), a Graphics Processing Unit (GPU) and a Central Processing Unit (CPU), such as all types of information communication devices, all types of multimedia devices, and application devices for all types of the information communication devices and all types of the multimedia devices, which support functions according to the various embodiments of the present disclsoure. For example, examples of the user device may include devices, such as a mobile communication terminal, a tablet Personal Computer (PC), a smart phone, a Portable Multimedia Player (PMP), a Media Player (e.g., an MP3 player), a portable game terminal, a Personal Digital Assistant (PDA), and the like, which operate according to communication protocols respectively matched to various communication systems. Also, a method for controlling a function, according to various embodiments of the present disclsoure, may be operated so as to be applied to various display devices, such as a laptop computer (e.g., a notebook), a PC, a Digital Television (TV), a Digital Signage (DS), a Large Format Display (LFD), and the like. The various embodiments described herein may be implemented in, for example, a recording medium readable by a computer or an apparatus similar to the computer by using software, hardware, or some combinations thereof For hardware implementation, the various embodiments described herein may be implemented by using at least one of Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and other electrical units for executing functions. Here, the recording medium may include a computer-readable recording medium storing a program for performing an operation of displaying a conversation exchanged through the messenger, an operation of detecting text related to content in the conversation, an operation of displaying a content image matched to the content on the background of the messenger, and an operation of providing information related to the content in response to the selection of the content image. In some cases, the various embodiments described in this specification may be implemented by the control unit170itself For software implementation, the various embodiments such as procedures and functions described in this specification may be implemented by separate software modules. Each of the software modules may perform one or more functions and operations described in this specification. FIGS.2A to2Dare views each illustrating an example of an operation of providing information through a messenger in a user device according to an embodiment of the present disclosure. In the various embodiments illustrated inFIGS.2A to2D, a case is described as an example in which a function related to content is a function of displaying a related website (or homepage). For example,FIGS.2A to2Deach illustrate an example of an operation of a case in which, when sightseeing (travel) content related to travel is recognized in input text, a content image as a background image is provided which has link information on a website from which a ticket can be booked in relation to the travel, and a travel-related website is provided in response to a user input selecting the content image. Referring toFIGS.2A to2D,FIG.2Aillustrates an example of a screen of the user device while the user of the user device executes the messenger and converses (chats) with at least one conversation partner through the messenger. As illustrated inFIG.2A, the messenger may provide an execution screen, which includes a background10which is basically set for the messenger or is set by the user; a speech bubble20which provides an identifier capable of identifying a subject of a conversation and the contents (e.g., text, an emoticon, an image, a moving image, etc.) of the conversation; and a text input window30which displays the contents of a conversation entered by the user. Also, the messenger may include a keypad40activated or deactivated in response to a user input. Referring toFIG.2A, the user device may display a conversation exchanged between the users through the speech bubble20. At this time, the user device may sense text of the exchanged conversation, and may detect text (e.g., characters, a word, a word sequence, etc.) matched to particular content by sensing the text. In an embodiment illustrated inFIG.2A, a state may be a state of detecting a content210related to “travel” in the text received from the conversation partner. According to an embodiment of the present disclsoure, the user device may recognize “travel” related to the sightseeing (travel) content through text sensing in the text reading “If you can take the time, let's take a trip.” received from the conversation partner. According to various embodiments of the present disclosure, a target user matched to text to be recognized may be set according to the user's selection. For example, the target user may be set so as to recognize only text entered by the user, may be set so as to recognize only text entered by the conversation partner, or may be set so as to recognize both the text entered by the user and the text entered by the conversation partner. According to an embodiment of the present disclosure, when the target user is set so as to recognize only text entered by the user, if the user device detects the input of text by the user of the user device in a conversation exchanged between the users, the user device may perform a text recognition operation. Alternatively, when the target user is set so as to recognize only text received from the conversation partner, if the user device detects the reception of text from the conversation partner in the conversation exchanged between the users, the user device may perform a text recognition operation. Alternatively, when the target user is set so as to recognize both the text entered by the user and the text received from the conversation partner, the user device may perform a text recognition operation on both the text entered by the user and the text received from the conversation partner in the conversation exchanged between the users. As illustrated inFIG.2B, when the text matched to the particular content has been detected, the user device may extract a content image220mapped to the particular content and may display the extracted content image220as a background of the messenger. As further illustrated inFIG.2B, the user device may display the content image220in between the original background10of the messenger and the speech bubble20, and may operate so that the speech bubble20may not be covered by the content image220. When displaying the content image220, the user device may count a set time period (e.g., 15 seconds, etc.), and enable the content image220to be displayed during the set time period. Then, when the set time period elapses, the user device may remove the content image220. Also, when new content is recognized in newly-input text while the content image220is displayed, the user device may extract a content image matched to the relevant content, and may operate so as to display the extracted content image. Further, in a state as illustrated inFIG.2B, the user device may select the previously-input text related to the particular content. Then, the user device may recognize content of text in response to a user input selecting the relevant text, may extract a content image matched to the recognized content, and may display the extracted content image. For example, according to an embodiment of the present disclsoure, the user device may provide a function of reading previously-provided information. In the state of displaying the content image220as illustrated inFIG.2B, the user may select (i.e., touch as indicated by reference numeral230) the displayed content image220, as illustrated inFIG.2C. Then, the user device may determine which function is related to the content image220(or content) in response to a user input230selecting the relevant content image220, and may operate so as to execute the related function. For example, as described above, the execution of a travel-related application, the display of a travel-related website, or the like may be set as a function mapped to the sightseeing (travel) content. Accordingly, as illustrated inFIG.2D, the user device may execute the function related to the sightseeing (travel) content, and may display an execution screen according to the execution of the function. According to an embodiment of the present disclsoure, the user device may operate so as to display a website related to content of the relevant text (e.g., travel) in response to a user input related to the content image220displayed as the background. Then, after displaying the relevant website, the user device may perform an operation (e.g., booking a ticket, etc.) related to the function executed in response to the user input. Alternatively, the user device may change the current screen to the screen illustrated inFIG.2Cin response to a user input for proceeding to the previous step, and may perform a messenger function. FIGS.3A to3Dare views each illustrating another example of an operation of providing information through a messenger in a user device according to an embodiment of the present disclosure. In the various embodiments illustrated inFIGS.3A to3D, a case is described as an example in which a function related to content is a search function. For example,FIGS.3A to3Deach illustrate an example of an operation of a case in which, when broadcast content related to a broadcast is recognized in input text, a content image as a background image is provided which has link information enabling the identification of a result of searching for the relevant broadcast content, and a result of searching for the relevant broadcast content on a portal site is provided in response to a user input selecting the content image. Referring toFIGS.3A to3D,FIG.3Aillustrates an example of a screen of the user device while the user of the user device executes the messenger and converses (chats) with at least one conversation partner through the messenger. Referring toFIG.3A, the user device may display a conversation exchanged between the users through the speech bubble20. At this time, the user device may sense text of the exchanged conversation, and may detect text matched to particular content by sensing the text. In an embodiment illustrated inFIG.3A, a state may be a state of detecting a content310related to a “broadcast” in the text entered by the user. According to an embodiment of the present disclsoure, the user device may recognize “drama” related to the broadcast content through text sensing in the text reading “I watch The King of Dramas.” entered by the user. As illustrated inFIG.3B, when the text matched to the particular content has been detected, the user device may extract a content image320mapped to the particular content and may display the extracted content image320as a background of the messenger. As further illustrated inFIG.3B, the user device may display the content image320in between the original background10of the messenger and the speech bubble20. When displaying the content image320, the user device may perform a control operation for exposing the relevant content image320during a set time period, or may perform a control operation for exposing the relevant content image320until the generation of a new event (e.g., the recognition of new content, the selection of text of the previous content, or the like). In the state of displaying the content image320as illustrated inFIG.3B, the user may select (i.e., touch as indicated by reference numeral330) the displayed content image320, as illustrated inFIG.3C. Then, the user device may determine which function is related to the content image320(or content) in response to a user input330selecting the relevant content image320, and may operate so as to execute the related function. For example, as described above, a function of searching for broadcast content of the recognized text and providing a result of the search may be set as a function mapped to the broadcast content. Accordingly, as illustrated inFIG.3D, the user device may execute the function related to the broadcast content, and may display an execution screen according to the execution of the function. According to an embodiment of the present disclsoure, the user device may operate so as to display a result of searching for content of the relevant text (e.g., The King of Dramas) on a portal site in response to a user input related to the content image320displayed as the background. Then, after displaying the relevant result of the search, the user device may perform an operation (e.g., detailed information display according to link selection matched to the relevant result of the search, etc.) related to the function executed in response to the user input. Alternatively, the user device may change the current screen to the screen illustrated inFIG.3Cin response to a user input for proceeding to the previous step, and may perform a messenger function. FIGS.4A to4Dare views each illustrating still another example of an operation of providing information through a messenger in a user device according to an embodiment of the present disclosure. In the various embodiments illustrated inFIGS.4A to4D, a case is described as an example in which a function related to content is the execution of an application. For example,FIGS.4A to4Deach illustrate an example of an operation of a case in which, when movie content related to movies is recognized in input text, a content image as a background image is provided which has link information enabling the execution of an application related to the relevant movie content, and the application related to the relevant movie content is executed and provided in response to a user input selecting the content image. Referring toFIGS.4A to4D,FIG.4Aillustrates an example of a screen of the user device while the user of the user device executes the messenger and converses (chats) with at least one conversation partner through the messenger. Referring toFIG.4A, the user device may display a conversation exchanged between the users through the speech bubble20. At this time, the user device may sense text of the exchanged conversation, and may detect text matched to particular content by sensing the text. In an embodiment illustrated inFIG.4A, a state may be a state of detecting a content410related to “movies” in the text entered by the user. According to an embodiment of the present disclosure, the user device may recognize “movie” related to the movie content through text sensing in the text reading “What about going to a movie?” received from the conversation partner. As illustrated inFIG.4B, when the text matched to the particular content has been detected, the user device may extract a content image420mapped to the particular content and may display the extracted content image420as a background of the messenger. As further illustrated inFIG.4B, the user device may display the content image420in between the original background10of the messenger and the speech bubble20. When displaying the content image420, the user device may perform a control operation for exposing the relevant content image420during a set time period, or may perform a control operation for exposing the relevant content image420until the generation of a new event (e.g., the recognition of new content, the selection of text of the previous content, or the like). In the state of displaying the content image420as illustrated inFIG.4B, the user may select (i.e., touch as indicated by reference numeral430) the displayed content image420, as illustrated inFIG.4C. Then, the user device may determine which function is related to the content image420(or content) in response to a user input430selecting the relevant content image420, and may operate so as to execute the related function. For example, as described above, a function of executing a movie-related application may be set as a function mapped to the movie content. Accordingly, as illustrated inFIG.4D, the user device may execute the function related to the movie content, and may display an execution screen according to the execution of the function. According to an embodiment of the present disclsoure, the user device may operate so as to execute an application related to content of the relevant text (e.g., movie) and display a relevant screen in response to a user input related to the content image420displayed as the background. Then, after displaying the screen according to the execution of the application, the user device may perform an operation (e.g., a movie search, the output of detailed information, purchase in advance, etc.) related to the function executed in response to the user input. Alternatively, the user device may change the current screen to the screen illustrated inFIG.4Cin response to a user input for proceeding to the previous step, and may perform a messenger function. FIGS.5A to5Dare views each illustrating yet another example of an operation of providing information through a messenger in a user device according to an embodiment of the present disclosure. In the various embodiments illustrated inFIGS.5A to5D, a case is described as an example in which a function related to content is to provide a particular coupon (e.g., a discount coupon, etc.) through the messenger. For example,FIGS.5A to5Deach illustrate an example of an operation of a case in which a discount coupon related to food content is provided when the food content related to food is recognized in input text. Referring toFIGS.5A to5D,FIG.5Aillustrates an example of a screen of the user device while the user of the user device executes the messenger and converses (chats) with at least one conversation partner through the messenger. Referring toFIG.5A, the user device may display a conversation exchanged between the users through the speech bubble20. At this time, the user device may sense text of the exchanged conversation, and may detect text matched to particular content by sensing the text. In an embodiment illustrated inFIG.5A, a state may be a state of detecting a content510related to “food” in the text entered by the user. According to an embodiment of the present disclsoure, the user device may recognize “hamburger” related to the food content through text sensing in the text reading “How about having a hamburger?” received from the conversation partner. As illustrated inFIG.5B, when the text matched to the particular content has been detected, the user device may extract a content image520mapped to the particular content and may display the extracted content image520as a background of the messenger. As further illustrated inFIG.5B, the user device may display the content image520in between the original background10of the messenger and the speech bubble20. When displaying the content image520, the user device may perform a control operation for exposing the relevant content image520during a set time period, or may perform a control operation for exposing the relevant content image520until the generation of a new event (e.g., the recognition of new content, the selection of text of the previous content, or the like). In the state of displaying the content image520as illustrated inFIG.5B, the user may select (i.e., touch as indicated by reference numeral530) the displayed content image520, as illustrated inFIG.5C. Then, the user device may determine which function is related to the content image520(or content) in response to a user input530selecting the relevant content image520, and may operate so as to execute the related function. For example, as described above, a function of providing a discount coupon may be set as a function mapped to the food content. Accordingly, as illustrated inFIG.5D, the user device may execute the function related to the food content, and may display an execution screen according to the execution of the function. According to an embodiment of the present disclsoure, the user device may operate so as to extract, internally or from the outside, a discount coupon540related to content of the relevant text (e.g., hamburger) and display the extracted discount coupon540through the speech bubble20in response to a user input related to the content image520displayed as the background. Then, after displaying the screen according to providing the discount coupon540, the user device may perform an operation (e.g., using (applying) the discount coupon540through a user input selecting (touching) the discount coupon540of the speech bubble20, etc.) related to the function executed in response to the user input. FIG.6is a flowchart illustrating a method for providing information through a messenger in a user device according to an embodiment of the present disclosure. Referring toFIG.6, the control unit170may execute a messenger and may display the executed messenger in operation601. For example, the control unit170may execute the relevant messenger and may display an execution screen related to the executed messenger, in response to a request from the user. The control unit170may sense a text input event in a state of executing the messenger in operation603. For example, the control unit170may receive text entered by the user or may receive text from at least one conversation partner. The control unit170may distinguish a transmission side from a reception side in a conversation (e.g., text entered by the user and text entered by the conversation partner) exchanged between the user and the conversation partner, and may separately display text on the transmission side and text on the reception side by using a speech bubble20. When the text input event has been sensed, the control unit170may sense the input text in operation605. For example, the control unit170may sense text (e.g., characters, a word, a word sequence, etc.) matched to particular content through text sensing in a conversation (chatting) exchanged through the messenger. For example, the control unit170may detect text related to the particular content (e.g., broadcast content, movie content, food content, sightseeing (travel) content, recording content, game content, etc.) in the conversation. According to an embodiment of the present disclsoure, the control unit170may sense text, which is based on a natural language used in the conversation (chatting), through character recognition. The term “natural language” refers to a concept enabling people to distinguish a language that people commonly use from an artificial language (or a machine language) which has been artificially invented. Then, the control unit170may analyze a mapping relation between the sensed text and preset text, and may determine whether there exist content related to the sensed text. Here, the control unit170may operate so as to recognize only text corresponding to a word/meaning related to particular content (or information) that the user has set. According to various embodiments of the present disclsoure, text sensing may be set so as to sense only text entered by the user, so as to sense only text received from the conversation partner, or so as to sense both the text entered by the user and the text received from the conversation partner. When the particular content has been identified through the text sensing, the control unit170may extract a content image related to the text (particularly, content) and may display the extracted content image in operation607. According to an embodiment of the present disclsoure, the content image may be provided as a background screen in an intermediate layer between the original background10of the messenger and the speech bubble20. In a state of displaying the content image, the control unit170may receive a user input related to the content image in operation609. For example, the user may select (i.e., touch) the content image in order to receive information by using the relevant content image displayed as the background of the messenger. When the content image has been selected, the control unit170may determine the type of the content in operation611. For example, the control unit170may identify an information providing scheme for providing information related to the relevant content. According to various embodiments of the present disclosure, examples of the type of content (i.e., the information providing scheme) may include the execution of an internal application, connecting to an external server and displaying a website, connecting to an external server and displaying a result of making a search on a portal site, acquiring and displaying a coupon, and the like. In this regard, the content types may be variously implemented. The control unit170may control the execution of an operation related to the content in operation613. For example, the control unit170may operate so as to execute a function matched to the type of content in response to the user input selecting the content image. Examples of this operation are illustrated inFIGS.2D,3D,4D and5D. FIG.7is a flowchart illustrating a method for providing information through a messenger in a user device according to an embodiment of the present disclosure. Referring toFIG.7, the control unit170may execute the messenger in response to a user input in operation701, and may sense a text input event in a state of executing the messenger in operation703. When the text input event has been detected, the control unit170may sense input text in operation705. According to various embodiments of the present disclsoure, a target user matched to text to be sensed may be set so as to sense at least one of text received from a conversation partner and text entered by the user, depending on the user's setting. The control unit170may detect content-related text by sensing the text in operation707. For example, the control unit170may analyze a mapping relation between the sensed text and preset text, and may determine whether there exists content related to the sensed text. When the text matched to particular content has been detected, the control unit170may extract a content image related to the text (particularly, content) in operation709. In operation711, the control unit170may display the extracted content image as a background. According to an embodiment of the present disclsoure, the content image may be provided as a background screen in an intermediate layer between the original background10of the messenger and the speech bubble20. After displaying the content image, the control unit170may determine whether a text input event exists in operation713. When the text input event is sensed (Yes in operation713), the control unit170may proceed to operation705, and may control the execution of an operation which follows. When the text input event is not sensed (No in operation713), the control unit170may determine whether the content image is selected, in operation715. When the content image is selected in a state of displaying the content image as the background (Yes in operation715), the control unit170may determine the type of content in operation717, and may analyze a function according to the determined type in operation719. For example, the control unit170may identify an information providing scheme for providing information related to the relevant content. Then, the control unit170may execute an internal function or a function of operating in cooperation with the outside, according to the identified information providing scheme, and may operate so as to display information related to content of the text, according to the executed function. In an embodiment of the present disclsoure, the internal function may include a function of executing an internal application installed in the user device and providing information related to content. Examples of the function of operating in cooperation with the outside may include a function of connecting to an external server and displaying a website of information related to content, a function of connecting to an external server and displaying a result of searching for information related to content on a portal site, a function of connecting to an external server before acquiring a coupon related to content and displaying the acquired coupon by using the speech bubble20, and the like. The control unit170may execute the analyzed function in operation721, and may control performing a relevant operation according to the executed function in operation723. For example, the control unit170may execute the relevant function in response to the user input selecting the content image, and may perform the operation according to the user input through the function executed as described in each of the examples illustrated inFIGS.2D,3D,4D and5D. When the content image is not selected in the state of displaying the content image as the background (No in operation715), the control unit170may determine whether text of the particular speech bubble20is selected in operation725. When the text of the particular speech bubble20is selected (Yes in operation725), the control unit170may identify content mapped to the selected text and may extract a content image matched to the identified content in operation727. Then, the control unit170may display the extracted content image as a background in operation729, and may control performing a relevant operation in operation731. For example, the control unit170may perform an operation of providing relevant information in response to a user input selecting a content image newly displayed as a background. Alternatively, the control unit170may perform the previous procedure in response to a user input selecting text of another speech bubble20. Alternatively, when a user input is not detected until a set time period elapses, the control unit170may perform an operation of removing the display of the content image as the background, and the like. When the text of the particular speech bubble20is not selected (No in operation725), the control unit170may determine whether a preset time period elapses in operation733. For example, the control unit170may count the set time period (e.g., 5 sec., 10 sec., 15 sec., etc.) from a time point of displaying the content image, and may operate so as to display a content image during the set time period. When the set time period does not elapse (No in operation733), the control unit170may control performing a relevant operation in operation737. For example, the control unit170may wait for a user input in a state of maintaining the display of the content image, and may perform, in response to the user input, an operation of displaying information related to content, an operation of displaying a new content image according to the selection of new text, an operation of receiving new text as input, and the like. When the set time period elapses (Yes in operation733), the control unit170may remove the content image being displayed as the background in operation735, and may control performing a relevant operation in operation737. For example, when the set time period elapses, the control unit170may remove the display of the content image as the background, and may operate so as to expose the original background10. Alternatively, in a state of removing the content image, the control unit170may proceed to operation703and may perform an operation that follows, as described above, or may terminate the messenger in response to a user input. Meanwhile, according to various embodiments of the present disclosure, each module may be implemented is software, firmware, hardware, or a combination thereof Also, some or all modules may be implemented in one entity, and a configuration may be implemented in which a function of each relevant module may be identically performed. According to the various embodiments of the present disclosure, operations may be performed sequentially, repeatedly, or in parallel. Further, some operations may be omitted or other operations may be added and executed. The above-described various embodiments of the present disclosure may be implemented in the form of program instructions executable through various computer means, and may be recorded in a computer-readable recording medium. The computer-readable recording medium may include a program instruction, a data file, a data structure, and the like, individually or in a combination thereof The program instructions recorded in the recording medium may be specially designed and configured for the present disclsoure, or may be known to and usable by those skilled in the field of computer software. Examples of the computer-readable recording medium may include magnetic media such as a hard disk, a floppy disk, and a magnetic tape, optical media such as a Compact Disc Read Only Memory (CD-ROM) and a Digital Versatile Disc (DVD), magneto-optical media such as a floptical disk, and hardware devices, such as a ROM, a RAM, a flash memory and the like, which are specially configured to store and execute program instructions. Also, examples of the program instructions may include a machine language code created by a compiler and a high-level language code executable by a computer by using an interpreter or the like. The above-described hardware device may be configured to operate as one or more software modules in order to perform an operation of the present disclosure, and vice versa. Also, the various embodiments of the present disclosure disclosed in this specification and the accompanying drawings are merely particular examples provided in order to clearly describe the technical contents of the present disclsoure and help in an understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. Accordingly, the scope of the present disclosure should be construed as including all modifications or changes in form, which may be made based on the technical idea of the present disclosure, as well as the various embodiments disclosed herein. As described above, the method and the apparatus for providing information by using a messenger, which the present disclosure proposes, can provide useful information to the users based on the text of a conversation exchanged between the users through the messenger of the user device. According to various embodiments of the present disclosure, the user device can detect a word/meaning of text entered by the user or conversation partner while the user chats with the at least one conversation partner by using the messenger. According to various embodiments of the present disclosure, the user device can extract a content image related to the word/meaning detected during the chatting, and can provide information related to the content image (or related to the text) in response to a user input related to the extracted content image. Accordingly, the user can receive the feedback of various pieces of information useful for the user simultaneously with the use of the messenger. Also, the user is provided with various pieces of useful information, various useful advertisements and the like through a conversation window of the messenger, so that an advertising effect can be maximized and accessibility to information by the user can be improved. Further, according to various embodiments of the present disclosure, the user can set the information providing apparatus so as to filter only text having a word/meaning related to content (or information) that the user desires, and thereby can be selectively provided with information. Therefore, according to various embodiments of the present disclsoure, the implementation of an optimal environment for providing useful and convenient recommendation information to the user in the user device can contribute to improving the convenience of the user and a developer and improving the usability, convenience and competitiveness of the user device. The above-described various embodiments of the present disclsoure can be implemented by the user devices of all forms, such as a mobile communication terminal, a smart phone, a tablet PC and a PDA, and by various devices each of which can support a function of providing information by using the messenger according to various embodiments of the present disclsoure. While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents. | 68,446 |
RE49891 | DETAILED DESCRIPTION OF THE INVENTION As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to particular modes of practice, and it is to be appreciated that all changes, equivalents, and substitutes that do not depart from the spirit and technical scope of the present invention are encompassed in the present invention. In the description of the present invention, certain detailed explanations of related art are omitted when it is deemed that they may unnecessarily obscure the essence of the invention. In the present specification, the terms such as “first” and “second” are used herein merely to describe a variety of constituent elements, but the constituent elements are not limited by the terms. The terms are used only for the purpose of distinguishing one constituent element from another constituent element. The terms used in the present specification are merely used to describe particular embodiments, and are not intended to limit the present invention. An expression used in the singular encompasses the expression of the plural, unless it has a clearly different meaning in the context. In the present specification, it is to be understood that the terms such as “including” or “having,” etc., are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof disclosed in the specification, and are not intended to preclude the possibility that one or more other features, numbers, steps, actions, components, parts, or combinations thereof may exist or may be added. One or more embodiments of the present invention will be described in detail with reference to the accompanying drawings. Turning now to the figures,FIG.1is a diagram illustrating a pixel electrode PE and an organic layer OL of an organic light-emitting display device according to an embodiment of the present invention,FIG.2is a diagram illustrating an active layer130of the organic light-emitting display device ofFIG.1,FIG.3is a diagram illustrating the organic light-emitting display device ofFIG.2further including a gate electrode GE layer,FIG.4is a diagram illustrating the organic light-emitting display device ofFIG.3further including a layer including a plurality of source and drain electrodes SE and DE,FIG.5is a diagram illustrating the organic light-emitting display device ofFIG.4further including a pixel electrode PE layer,FIG.6is a cross-sectional view taken along a line I-I′ ofFIG.5andFIG.7is a partial cross-sectional view of an organic light-emitting device (OLED) included in the organic light-emitting display device ofFIG.1. First, first, second, and third sub-pixels P1, P2, and P3each including first through third switching devices TR1through TR3and various circuit components are formed on a substrate1or on a buffer layer11formed on the substrate1. Referring toFIG.1, the organic light-emitting display device of the current embodiment includes the first, second, and third sub-pixels P1, P2, and P3. The first, second, and third sub-pixels P1, P2, and P3may constitute a single unit pixel P. For example, the single unit pixel P may include a red sub-pixel R, a green sub-pixel G, and a blue sub-pixel B, however the present invention is not limited thereto. Hereinafter, the red sub-pixel R, the green sub-pixel G, and the blue sub-pixel B may respectively refer to the first sub-pixel P1, the second sub-pixel P2, and the third sub-pixel P3. Each of the first through third sub-pixels P1through P3may include at least one capacitor Cst, at least one thin-film transistor (TFT), and an OLED. For example, each sub-pixel may include six TFTs and two capacitors Cst. In this regard, the TFTs may include a driving transistor that is electrically connected to the OLED and at least one switching transistor. According to the current embodiment of the present invention, the TFT and the capacitor Cst that are included in each sub-pixel may be turned-on to be electrically connected to a switching device receiving an initializing voltage or signal. For example, the first sub-pixel P1, the second sub-pixel P2, and the third sub-pixel P3are electrically connected to the first switching device TR1, the second switching device TR2, and the third switching device TR3, respectively. In this regard, each of the first through third switching devices TR1through TR3may be a kind of TFT. Referring now toFIG.4, the first switching device TR1includes a first active layer131to form a channel, a first gate electrode GE1insulated from the first active layer131, a first source electrode SE1and a first drain electrode DE1electrically connected to the first active layer131. The second switching device TR2includes a second active layer132to form a channel, a second gate electrode GE2insulated from the second active layer132, a second source electrode SE2and a second drain electrode DE2electrically connected to the second active layer132. The third switching device TR3includes a third active layer133to form a channel, a third gate electrode GE3insulated from the third active layer133, a third source electrode SE3and a third drain electrode DE3electrically connected to the third active layer133. Referring now toFIG.2, the first active layer131, the second active layer132, and the third active layer133are connected to one another and are illustrated as the active layer130inFIG.2. The first through third active layers131through133are formed together when another active layer135is formed. For example, the active layer130may be made out of an amorphous silicon layer, a polycrystal silicon layer, or an oxide semiconductor layer such as a G-I—Z—O layer [(In2O3)a(Ga2O3)b(ZnO)clayer, wherein a, b, and c are real numbers that satisfy conditions a≥0, b≥0, and c>0, respectively]. According to the current embodiment of the present invention, the first through third active layers131through133are connected to one another, and thus an initializing signal applied from an initializing electrode VLi (seeFIG.5) may be transmitted to the first through third sub-pixels P1through P3. Referring now toFIG.3, the first through third gate electrodes GE1through GE3are connected to one another. The first through third gate electrodes GE1through GE3are formed together when an n-1-th gate line GLn-1and another gate electrode150are formed. In this regard, the n-1-th gate line GLn-1transmits an n-1-th scanning signal Sn-1to turn on the first through third switching devices TR1through TR3. Referring now toFIG.4, according to the current embodiment of the present invention, the first through third switching devices TR1through TR3may include one of a commonly formed drain electrode or a commonly formed source electrode. In detail, referring toFIG.4, the first through third switching devices TR1through TR3may commonly form the first source electrode SE1, the second source electrode SE2, and the third source electrode SE3. Accordingly, the source electrodes commonly formed may be referred to a common source electrode SEc. Also, as illustrated inFIG.4, the common source electrode SEc has an island shape and may be arranged to be spaced apart from otherwiringswiringformed from the same layer whichformformsthe drain electrode and a lower electrode of the capacitor Cst, however, although not shown, the present invention is not limited thereto. Alternatively, the first drain electrode DE1, the second drain electrode DE2, and the third drain electrode DE3may be commonly formed, which may refer to a common drain electrode. According to the current embodiment of the present invention, an organic light-emitting display device includes just a single via-hole VH is formed to provide electrical connection to the common source electrode SEc to deliver an initializing signal to each of the first through third sub-pixels P1through P3. Also, a scanning signalthatis transmitted to the first through third gate electrodes GE1through GE3, and thus each of the first through third switching devices TR1through TR3are turned on. Then, an initializing signal is applied to the common source electrode SEc and a channel is formed in each of the first through third active layers131through133, and thus the initializing signal may be transmitted to the first through third drain electrodes DE1through DE3. That is, the first through third switching devices TR1through TR3may simultaneously transmit the initializing signal to the first through third sub-pixels P1through P3due to the common source electrode SEc. Referring now toFIG.6, a gate insulating layer13for insulating the active layer130from the gate electrode GE layer may be formed between the active layer130and the gate electrode GE. Also, and insulating interlayer15is formed on the gate electrode GE. The gate insulating layer13and the insulating interlayer15may be made out of silicon oxide, tantalum oxide, aluminum oxide, or the like, but the present invention is not limited thereto. Referring now toFIGS.4and6, also, the common contact hole CTc may be formed in the gate insulating layer13and in the insulating interlayer15to electrically connect the common source electrode SEc to the active layer130. That is, the common contact hole CTc is formed in portions where the gate insulating layer13and the insulating interlayer15are partially removed, to expose the active layer130in correspondence to an area where the common source electrode SEc is to be formed. Since the common contact hole CTc is related to the common source electrode SEc, just one common contact hole CTc is needed to provide electrical connection from common source electrode SEc to each of first through third sub-pixels P1through P3. Referring now toFIG.4, the first through third drain electrodes DE1through DE3may also be electrically connected to the active layer130. Although not shown inFIG.4, each of the first through third drain electrodes DE1through DE3contacts and is electrically connected to the other active layer135that is connected to the first through third active layers131through133, however the present invention is not limited thereto. Each of the first through third drain electrodes DE1through DE3may instead contact and be electrically connected to any portion of the active layer130. Referring now toFIG.6, a planarization layer17is formed on the first through third switching devices TR1through TR3. In detail, the planarization layer17is formed on each of the first through third drain electrodes DE1through DE3and the common source electrode SEc. The planarization layer17may be formed to planarize an uneven surface due to the underlying structure, however, the present invention is not limited thereto. A passivation layer for protecting the switching devices may further be formed under the planarization layer17. The via-hole VH is formed in the planarization layer17. The via-hole VH is formed in portions where the planarization layer17is partially removed, to expose the common source electrode SEc in correspondence to an area where the common source electrode SEc is arranged. The via-hole VH is arranged at a location that corresponds to the common source electrode SEc, and thus just one via hole VH is needed to provide electrical connection to each of the first through third sub-pixels P1through P3. The initializing electrode VLi contacts and is electrically connected to the common source electrode SEc via the via-hole VH. Referring toFIG.5, the via-hole VH may be formed near the common contact hole CTc. The via-hole VH allows the initializing electrode VLi to electrically connect to the common source electrode SEc, and the common contact hole CTc allows the common source electrode SEc to electrically connect to the active layer130. That is, the via-hole VH is formed to correspond to the common source electrode SEc. According to the current embodiment of the present invention, the common source electrode SEc is formed to have an island shape, and thus the via-hole VH and the common contact hole CTc are formed close to each other. Referring now toFIG.5, the initializing electrode VLi receives an initializing voltage or an initializing signal from the outside and transmits the initializing voltage or the initializing signal to the common source electrode SEc electrically connected thereto. According to the current embodiment of the present invention, the initializing electrode VLi may be formed from the same layer as the pixel electrode PE. Turning now toFIG.7,FIG.7illustratesFIGS. 1 and 7 illustratethe OLED included in each sub-pixel. The OLED includes the pixel electrode PE formed on the planarization layer17, the organic light-emitting layer OL formed on the pixel electrode PE, and a counter electrode200covering the organic layer OL and formed on the entire sub-pixel. Although not shown inFIG.7, the OLED is electrically connected to a driving transistor (not shown) included in the sub-pixel. In detail, similar to the first through third switching devices TR1through TR3, the planarization layer17is formed on the driving transistor, and the pixel electrode PE and driving transistor contact each other via a hole formed in the planarization layer17. After the pixel electrode PE is formed, a pixel-defining layer19is formed on at least a part of the pixel electrode PE to expose the at least a part of the pixel electrode PE by a pixel opening OA. The organic light-emitting layer OL is formed on the pixel electrode PE exposed by the pixel opening OA so that the pixel opening OA includes an organic light-emitting layer. As discussed previously in conjunction withFIG.1, the first through third sub-pixels P1through P3may be formed to have different types of organic light-emitting layers. The counter electrode200is formed on the organic layer OL and the pixel electrode PE. The counter electrode200is formed to entirely cover a layer including the pixel-defining layer19and the organic layer OL. Accordingly, if a voltage is applied from the driving transistor to the pixel electrode PE and thus an appropriate voltage condition is formed between the pixel electrode PE and the counter electrode200, light emission occurs in the OLED. In a top emission type display, in which an image is displayed toward the counter electrode200, the pixel electrode PE may be a reflective electrode and the counter electrode200may be a light-transmitting type electrode. In this case, the counter electrode200may include a semi-transmission reflective layer made out of any one material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, and Ca and formed to be thin, or may include a light-transmitting metal oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO). In a bottom emission type display, the counter electrode200may have a reflection function by being deposited with any one material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, and Ca. When the pixel electrode PE is used as an anode, the pixel electrode PE may include a layer made out of a metal oxide having a high work-function (an absolute value), for example, ITO, IZO, or ZnO. When the pixel electrode PE is used as a cathode, the pixel electrode PE may include a highly conductive metal having a low work-function, for example, Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, or Ca. When the pixel electrode PE is used as an anode, the counter electrode200may be used as a cathode, or vice-versa. Also, according to the current embodiment of the present invention, the initializing electrode VLi may be made out of the same material and be arranged on the same layer as the pixel electrode PE. That is, after a metal layer constituting of the pixel electrode PE is formed, the initializing electrode VLi and the pixel electrode PE are patterned at the same time. As illustrated inFIGS.5and6, both the pixel electrode PE and the initializing electrode VLi are formed on the planarization layer17, and thus both may be formed from the same layer. First, according to the current embodiment of the present invention, when the initializing electrode VLi and the pixel electrode PE of the OLED are formed from the same layer, a spatial gain is obtained in which the capacitor Cst disposed of a different layer from the pixel electrode PE may be formed to have a high capacity. When the initializing electrode VLi is formed from the same layer as a gate wiring, a longitudinal length of the sub-pixel is reduced in order to secure a space for the initializing electrode VLi to be disposed in a row direction. The capacitor Cst is formed by using the other gate electrode150formed from the same layer as the gate electrode of the sub-pixel as a lower electrode and using a wiring formed from the same layer as the source/drain electrode as an upper electrode. Accordingly, when the longitudinal length of the sub-pixel is reduced in order to secure a space for the initializing electrode VLi, an area of the capacitor Cst is reduced. Consequently, a high resolution pixel may not secure a sufficient charging capacity. However, according to the current embodiment of the present invention, the area of the capacitor Cst is not reduced by forming the initializing electrode VLi from the pixel electrode PE layer. Turning now toFIG.8,FIG.8is a diagram illustrating an organic light-emitting display device according to a comparative example of the present invention and the organic light-emitting display device illustrated inFIG.1. Differences between the organic light-emitting display device according to the comparative example of the present invention and the organic light-emitting display device illustrated inFIG.1will now be described with reference toFIG.8. FIG.8(a)illustrates the organic light-emitting display device in which first through third switching devices TR1through TR3corresponding to each sub-pixel do not have a common source electrode SEc, and thus a via-hole VH is formed for each sub-pixel. FIG.8(b)illustrates the organic light-emitting display device illustrated inFIG.1in which the common source electrode SEc is formedincommontowiththe first through third switching devices TR1through TR3respectively corresponding to the first through third sub-pixels P1through P3, and thus a single via-hole VH is formed common to the first through third sub-pixels P1through P3. Referring toFIG.8(b), an area where the via-holes VH ofFIG.8(a)are formed may provide a space where the pixel openings OA may be formed larger. In this regard, the pixel opening OA, as described above, is a portion where the pixel-defining layer19is removed from at least a part of an upper portion of the pixel electrode PE to expose at least apart of the pixel electrode PE and where light emission occurs, wherein the pixel opening OA is covered by the organic light-emitting layer OL. Experimentally, aperture ratios of the first and second sub-pixels P1and P2ofFIG.8(b)are increased by about 11.7%, compared to those ofFIG.8(a). Also, an aperture ratio of the third sub-pixel P3ofFIG.8(b)is increased by about 13.5%, compared to that ofFIG.8(a). As such, an organic light-emitting display device designed to increase an aperture ratio has a longer lifespan and an increased image quality. Also, the organic light-emitting display device according to the embodiment of the present invention is manufactured according to the above-described operations. In short, the substrate1is prepared, and the buffer layer11is formed on the substrate1, and then the active layer130is formed on the buffer layer11, as illustrated inFIG.2. When the active layer130is patterned, the first through third active layers131through133may be connected to one another. Also, the other active layer135to be used as a lower electrode of the capacitor Cst may be patterned to be connected to the first through third active layers131through133. Next, the gate insulating layer13is formed on the active layer130. Then, as illustrated inFIG.3, the gate electrode GE layer is formed on the gate insulating layer13and is then patterned. At this point, the first through third gate electrodes GE1through GE3and the gate line GLn-1may be patterned to be connected to one another. Next, the insulating interlayer15is formed on the gate electrodeGE. Then, the common contact hole CTc is formed by partially removing the insulating interlayer15and the gate insulating layer13. Then, as illustrated inFIG.4, the metal layer is formed thereon and is then patterned to form the source and drain electrodes SE and DE. At this point, the metal layer is patterned to form a wiring corresponding to an upper electrode of capacitor Cst, the common source electrode SEc and the first through third drain electrodes DE1through DE3. The common source electrode SEc contacts the active layer130via the common contact hole CTc. Next, the planarization layer17is formed on the source/drain metal, and the via-hole VH is formed in the planarization layer17. Then, as illustrated inFIG.5, a metal pixel electrode PE layer is formed on the planarization layer17to form the pixel electrode PE and the initializing electrode VLi by patterning the metal pixel electrode PE layer. In this regard, the initializing electrode VLi contacts the common source electrode SEc via the via-hole VH. Next, the pixel-defining layer19is formed on the pixel electrode PE metal. In this regard, the pixel opening OA is formed in an area of the pixel electrode PE where a light emission unit is to be formed by partially removing the pixel-defining layer19. The organic light-emitting layer OL is deposited on the pixel electrode PE exposed by the pixel opening OA. Then, the counter electrode200isentirelyformed on theentireties of theorganic light-emitting layer OL and on the pixel-defining layer19. Turning now toFIG.9,FIG.9is a circuit diagram illustrating switching devices according to an embodiment of the present invention. Referring toFIG.9, unlikeFIG.1, only a single via-hole VH is formedto accommodate initializing electrode VLi, and a source terminal of each of first through third switching devices TR1through TR3is connected to a common node. Portions illustrated as a resistor R in the common node are portions that are electrically connected to each other by an active layer130. InFIG.9, Vi denotes an initializing voltage and Sn-1denotes an n-1-th scanning signal for turning on each of the first through third switching devices TR1through TR3. According to the present invention, when an initializing electrode and a pixel electrode of an OLED are formed from the same layer, a spatial gain is obtained in which a capacitor disposed on a different layer from the pixel electrode may be formed to have a high capacity. Also, according to the present invention, any one of a drain electrode and a source electrode of switching devices corresponding to each sub-pixel is commonly formed and thus a via-hole is formed common to a plurality of sub-pixels, so that an area where a via-hole is formed in each sub-pixel may provide a space where a pixel opening may be formed larger, thereby increasing an aperture ratio of an organic light-emitting display device. While the present invention has been particularly shown, and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form, and details may be made therein without departing from the spirit, and scope of the present invention as defined by the following claims. | 23,714 |