James Kramer and his supervisor, Larry Leifer, have been working on a method for communication between Deaf, Deaf-Blind and Non-vocal individuals. It is a complete system, which attempts to integrate a number of technologies together, in such a way that all parties can communicate. This is shown in thefigure below.
Of interest and relevance to us is the glove Kramer developed (the CyberGlove) and the technology used for recognizing American finger-spelling.
At the moment, the system has acceptable finger-spelling performance, and James Kramer has set up a company, called Virtual Technologies, to market the system. In September 1995 VirTex released a commercial finger-spelling recognition package called GesturePlus. However, the system costs US$3500, and this price does not include the CyberGlove.
Initially, he used a prototyping algorithm. There were prototypes for each letter, which Kramer termed ``beacons''. These beacons which are points in the hand state vector space, are then surrounded by hyperspheres. When a hand enters the the hypersphere, a letter is produced. This hypersphere, which Kramer calls a ``recognition ball'', lies within another hypersphere, which Kramer terms the ``hysteresis ball''. To repeat a sign, the hand must move outside the hysteresis ball, before another handshape is recognised (this intuitively makes sense, since when finger-spelling and a sign is to be repeated, it is typically made distinct in a similar manner -- ie the gesture is repeated twice). See figure below. This shows the hand-state moving through a vector space, which in this case is simplified to three dimensions, but there are 16 dimensions in the actual model.
The above system has been road-tested and has been shown to be practical.
Currently, Kramer is working on moving the above model to a neural-network implementation, and also broadening the scope to more than finger-spelling -- that is to full signs.