MAP decoding of gray-level images over binary channels with memory

A joint source-channel coding technique is proposed for transmitting grey-level images over a binary channel with additive Markov noise. In this scheme, inherent or residual (after source coding) image redundancy is exploited at the receiver in an appropriately designed MAP detector. Two methods are presented. The first method relies on MAP decoding of uncompressed bit-plane encoded images. The second method deals with compressed images (DCT coded and quantized) and uses unequal error protection along with the MAP detection procedure. Experimental results demonstrate that particularly during bad channel conditions, significant performance improvements can be achieved