Optimized sign language video coding based on eye-tracking analysis

The imminent arrival of mobile video telephony will enable deaf people to communicate - as hearing people have been able to do for a some time now - anytime/anywhere in their own language sign language. At low bit rates coding of sign language sequences is very challenging due to the high level of motion and the need to maintain good image quality to aid with understanding. This paper presents optimised coding of sign language video at low bit rates in a way that will favour comprehension of the compressed material by deaf users. Our coding suggestions are based on an eye-tracking study that we have conducted which allows us to analyse the visual attention of sign language viewers. The results of this study are included in this paper. Analysis and results for two coding methods, one using MPEG-4 video objects and the second using foveation filtering are presented. Results with foveation filtering are very promising, offering a considerable decrease in bit rate in a way which is compatible with the visual attention patterns of deaf people, as these were recorded in the eye tracking study.