Moving picture transmission at low bitrates for sign language communication

Sign language is as fast as speech, and so the ability to transmit moving pictures of sufficient quality for sign language over telephone and other networks would enable deaf people to use their most efficient means of communication, as well as allowing far more interactive and personally satisfying conversations. The author describes the development of an experimental videophone for sign language communication that works over the normal Public Switched Telephone Network (PSTN) using a 14.4 kbit/s modem. The key module in the videophone is a video codec (coder/decoder) that implements an image compression algorithm allowing transmission of moving images at a data rate of only 14.4 kbit/s