Direct pointing devices such as the light pen have been demonstrated to be extremely useful in some applications. For example, head mounted light pens combined with special software for emulating keyboards on a computer display have been found to be very useful for disabled individuals who find it difficult or impossible to use keyboards. Three problems with traditional light pens have been identified. First, traditional light pens do not work when pointed to areas of the screen containing dark colors. Second, different computer/display combinations require different light pen adjustments and calibration. Third, a growing number of new display technologies do not employ a raster scan (a feature necessary for traditional light pens). The last point is especially of concern for the disabled community because of the increased portability and utility offered by laptop and portable computers which use non-raster liquid crystal displays. Consequently, there is a need to develop a direct pointing device that will overcome these problems. The goal of the proposed work is to test different approaches and demonstrate the feasibility of a direct pointing device that will operate on non-raster displays.
The proposed research could lead to the d envelopment of a new pointing device which is compatible with liquid crystal displays. Such a product will be important for members of the disabled community for whom portable computers offer a tremendous advantage.
