Robust image communication using bandwidth reducing and expanding mappings

Combined source-channel coding can be an efficient way to exploit a noisy channel for transmitting signals representing natural sources. In this paper, we propose a coding system for transmission of still images on a time discrete, amplitude continuous, additive white Gaussian noise channel. The coder is an extension of earlier work by Lervik and Ramstad (1996). We introduce a method for bandwidth expansion which gives extra protection to the most important symbols. An improvement of the PSNR up to 5 dB is demonstrated for the proposed coder compared to the reference coder.