"KnowWare: virtual reality maps for blind people"

Much has been done to give blind people access to text-based information through computers. Unfortunately, the recent development of Windows operating systems and GUIs jeopardize these gains. Spatial information which is becoming more important to the sighted has never been widely available to blind people. Through a combination of gesture input with audio output, the KnowWare system offers blind users a new way to access spatial information. An invisible virtual map is defined on the desktop. When the user touches a feature on the map with the tip of his index finger, the computer tells him what he has touched by means of computer-generated speech or synthesized sound codes. Touching is detected by means of an overhead video camera that looks down at the user's hands as they rest upon the desktop. Specialized processors analyze the image of the user's hands and locate the fingertips. Because KnowWare is an electronic medium, it is possible to instantly zoom in on a particular state or country to examine it in more detail. Similarly, panning and overlays are possible. Twenty blind subjects have tested KnowWare and have been able to use it as well as they do traditional raised-line maps.