1. Field of the Invention
The present invention relates generally to display control apparatus and program, and more particularly to such display and control apparatus and program for displaying both video and character information on a television receiver.
2. Description of the Related Art
In television broadcasts, the practical use of ground-wave television broadcasts as well as BS (Broadcast Satellite) digital broadcasts has been advanced in a digital system. In such digital television broadcast, character information including news flashes and/or subtitles combined in a multiplexed manner is received in addition to the video information. The receiver processes images on the character information as well as the received video information, thereby customizing the display colors, sizes and/or fonts of the characters included.
In the past, many proposals have been made for receivers that receive the BS digital broadcasts and ground-wave television broadcasts. For example, Published Unexamined Japanese Patent Application Hei 11-8807 discloses a digital broadcast receiver by which the viewer can easily recognize the content of a program being broadcasted in each channel at present and display in a short time a list of channels that inform the viewer of channel information available. According to this arrangement, when character information representing respective channel programs and titles of all or part of receivable channels is displayed in the list of channels, this list and images of programs being broadcasted at present in certain ones of the channels of the list are displayed.
Published Unexamined Japanese Patent Application 2000-50220, discloses a teletext receiver by which the viewer can easily recognize what teletext programs are being broadcasted at present and easily select a desired program. This publication discloses means for displaying a plurality of teletext programs decoded or a plurality of pages of the same program each in a compressed state on a smaller picture than the original display screen and superimposed such that they are shifted sequentially by at least one line.
Published Unexamined Japanese Patent Application 2002-199354 discloses a digital broadcast receiver in which the size of a display area for character information and the display position of the character information are changeable. In this arrangement, even when a television broadcast program is displayed in a compressed manner, corresponding credit titles can be displayed in an easy-to-see manner. This arrangement comprises a controller that changes a value of control information annexed to the received character information based on a display position of a video picture of the television broadcast program received, thereby moving the display position of the character information on the picture.
Published Unexamined Japanese Patent Application 2002-353829 discloses a ground-wave digital broadcasting receiver and an information acquiring and supplying apparatus in which even when the viewer moves from his or her reception area during viewing a program, he or she is able to continue to view the program that he or she has viewed so far. According to this arrangement, when a ground-wave digital broadcast is received and demodulated, thereby providing its video and voice signals, the viewer acquires station select information from an information source, for example an FM teletext, different from the ground-wave digital broadcast and then selects a desired station based on the acquired station select information.
Published Unexamined Japanese Patent Application 2002-353915 discloses a mobile information terminal that performs a schedule management function, a calendar function, a simple-document creating function, an electronic mail function and a function to receive a partial service of the ground-wave digital broadcast. This terminal comprises a tuner that selects a ground-wave digital broadcast and produces a corresponding transport stream, a separator that extracts added information from the transport stream, a generator that generates an electronic program guide image based on the added information, a specifying unit that specifies any one of displayed programs on the electronic program guide picture and a delivering unit that delivers information that specifies the specified program directly or via an externally connected communication device to an output line. Further, it produces a data broadcast image based on the added information.
Published Unexamined Japanese Patent Application 2003-161620 discloses a car navigation system that uses a ground-wave digital broadcast to receive area information such as area map information included in the ground-wave digital broadcast. This system comprises a stored-data reader that reads desired map data from map media that have stored map data, a broadcast receiver that receives the ground-wave digital broadcast, a storage device that has stored map data, position sensing means that detects the present position of the user's car using a GPS, a display that displays the map data, an input device by which the user can select information, and a control processor that controls these elements.
Although these prior art technical literatures disclose techniques for displaying video and character information, they fail to refer to image processing for character information in consideration of video information that represents the background of characters to be displayed.
In the digital broadcast, credit titles to be displayed in association with the content of the television broadcasting program are arranged to be displayed at a predetermined position on a displayed picture of the television broadcasting program by the teletext including data, characters and credit titles. Especially, in the Published Unexamined Japanese Patent Application 2002-199354 an arrangement is disclosed that solves a problem that when the television broadcasting program and the data broadcast content are displayed in a multi-picture screen, the data broadcast content is difficult to view because it is hidden by the credit titles. The technique automatically calculates a value of a position where the credit titles start to be displayed with the position of a lower left corner of the video picture as a reference in a state in which the video picture of the television broadcasting picture is displayed in a compressed manner, and displays the credit titles near the video picture in an easy-to-see manner. However, this technique does not solve a problem that when displayed, superimposed on the video information that represents the background, the character information will be difficult to view.
Usually, the character information is displayed, superimposed on the video information that represents the background. Thus, it is difficult to discriminate the character information from its background depending on the content of the background, thereby lowering the distinction of the character information. For example, when the video is similar in display color to the characters or the contrast in brightness between the video and the characters is small, the distinction of characters is low and the characters are difficult to recognize. When a news flash, for example, of a natural disaster or accident is displayed in large characters on the picture to attract the viewers' attention, the picture quality would greatly be deteriorated.