Several technologies exist that adapt a display screen or display surface associated with a computer to be interactive. An interactive display screen or surface is adapted to allow detection of inputs at the surface thereof, and is often referred to simply as an interactive surface. The detected inputs at the interactive surface can be used to manipulate objects displayed on the surface, annotate the display surface, and generally control software applications running on the computer in a similar way to a conventional computer mouse.
Example known interactive surfaces are adapted to detect touch inputs on the surface, or detect the presence of specially adapted input devices, such as pen-type devices.
In general, interactive surfaces adapted for use with pens advantageously have a greater input detection resolution than touch input surfaces.
However, in some scenarios a touch sensitive interactive surface may be a preferable implementation. Touch sensitive interactive surfaces tend to be used for providing solutions in public kiosk implementations, where special pens are not available or not desirable. The relative cost of touch and pen implementations are such that cost factors may dictate a touch solution for some implementations. Further, in some applications, a touch solution may have particular advantages. An example of such an application is the use of an electronic whiteboard system incorporating an interactive surface in an educational environment for young children, where having to control a pen to use the whiteboard on a vertical surface can be problematic for users. A touch surface may also be more suited to an environment in which multiple users provide inputs at the interactive surface at the same time.
Thus sometimes a trade-off must be made in terms of the pen or touch positioning location accuracy (which may be best provided by a pen-type interactive surface) against cost, speed of response, or capability to cope with many simultaneous touches (which may be best provided by a touch-type interactive surface). Often all of these factors are interrelated.
This may lead to a situation where in a given implementation the image pixel resolution of the displayed image is greater than the resolving resolution of the touch sensing technology, i.e. the display resolution is greater than the detection resolution.
For the purposes of basic control and annotation, this disparity between resolutions is rarely a problem. However for situations where objects must be moved and located with precision, a problem arises. An example of such a scenario is the use of a touch sensitive interactive whiteboard in an education environment. Consider an example implementation in a mathematics application where it is required for a user to control the position of an on-screen virtual protractor to make a precise measurement. Without pixel-accurate movement control, which requires the detection resolution to be compatible with the display resolution, this may not be possible.
It is an object of the invention to provide an improved arrangement to address one or more of the above-stated problems, and provide for finer control of the transformation of a displayed object in a system where the image pixel resolution of a displayed image is greater than the resolving resolution of the input sensing technology.