Progressive transmission of images using MAP detection over channels with memory

We propose a new maximum a posteriori (MAP) detector, without the need for explicit channel coding, to lessen the impact of communication channel erro rs an compressed image sources, The MAP detector exploits the spatial corre lation in the compressed bitstream as well as the temporal memory in the ch annel to correct channel errors, We first present a technique for computing the residual redundancy inherent in a Compressed grayscale image (compress ed using VQ). The performance of the proposed MAP detector is compared to t hat of: a memoryless MAP detector. We also investigate the dependence of th e performance on memory characteristics of the Gilbert-Elliott channel as w ell as average Channel error rate. Finally, we study the robustness of the proposed MAP detector's performance to estimation errors.