Robust EZW image coding for noisy channels

We present a new embedded zerotree wavelet image coding algorithm that is based on the algorithms developed by Shapiro (see IEEE Trans. Signal Processing, Spec. Issue Wavelets Signal Processing, vol.41, no.12, p.3445-62, 1993) and Said et al. (see IEEE Trans. Circuits Syst. Video Technol., vol.6, no.6, p.243-50, 1996). Our algorithm features a relatively simple coding structure and provides a better framework for balancing between high compression performance and robustness to channel errors. The fundamental approach is to explicitly classify the encoder´s output bit sequence into subsequences, which are then protected differently according to their importance and robustness. Experimental results indicate that, for noisy channels, the proposed algorithm is slightly more resilient to channel errors than more complex and sophisticated source-channel coding algorithms. More important is that our algorithm is substantially more robust with respect to varying channel error conditions. This provides much needed reliability in low-bandwidth wireless applications.