Progressive transmission of images over memoryless noisy channels

An embedded source code allows the decoder to reconstruct the source progre ssively from the prefixes of a single bit stream. It is desirable to design joint source-channel coding schemes which retain the capability of progres sive reconstruction in the presence of channel noise or packet loss. Here, we address the problem of joint source-channel coding of images for progres sive transmission over memoryless bit error or packet erasure channels. We develop a framework for encoding based on embedded source codes and embedde d error correcting and error detecting channel codes. For a target transmis sion rate, we provide solutions and an algorithm for the design of optimal unequal error/erasure protection. Three performance measures are considered : the average distortion, the average peak signal-to-noise ratio, and the a verage useful source coding rate. Under the assumption of rate compatibilit y of the underlying channel codes, we provide necessary conditions for prog ressive transmission of joint source-channel codes. We also show that the u nequal error/erasure protection policies that maximize the average useful s ource coding rate allow progressive transmission with optimal unequal prote ction at a number of intermediate rates.