Region of interest priority coding for sign language videoconferencing

This paper investigates compression of sign-language video sequences for transmission over low bitrate channels. The motion of hands and arms inherent in sign language requires high temporal resolution and greater compression for band-limited channels. Most existing compression schemes treat the entire image uniformly. However, the background is much less critical than the foreground for sign language communication. A new algorithm is developed that gives priority to the foreground and sacrifices the quality of the background to achieve higher compression rates and higher foreground quality without compromising the frame rate. The algorithm is extended to use a dynamic region of interest defined by face and hand location. Results show that the frame rate and quality of the region of interest are higher than with uniform algorithms.