Constrained error propagation for efficient image transmission over noisy channels

Multimedia applications increasingly require efficient transmission of still and moving images over wireless channels. However, wireless channels originally designed for voice transmission impose severe bandwidth constraints on image data. In addition, data transmitted over wireless channels are subject to degradation due to such phenomena as burst noise and fading that cause errors. The JPEG standard has been developed for image data compression necessary for efficient transmission. The emerging JPEG-2000 standard addresses the transmission error problem by including provisions for error-resilience tools. These include resynchronization, data recovery and error concealment. In this paper, we survey current error resilience techniques for image data, and focus on the synchronization aspect of error resilience. In particular, we propose an application of self-synchronizing variable length codes (VLC) to achieve the dual goal of efficient source coding and constrained error propagation to localize the effects of data corruption. This makes subsequent data recovery and error concealment more effective. Performance analysis of the proposed technique is also presented