In this article, the development of an efficient and reliable multiple description coding (MDC) scheme over unreliable communication networks is described. A general framework of multiple description robust communication system with 2-and 4-channel cases is presented with a proposed block-based dc separation approach. The advantage of this system is that, if all the channels work, a high quality reconstruction can be achieved, while a lower but still acceptable quality can be achieved if some of the channels are lost. The peak signal-to-noise ratio (PSNR), mean squared error (MSE), bit rate, entropy and redundancy are also calculated with the proposed method to analyze the reconstruction quality. It is found that the proposed method gives comprehensive improvements over the other recently developed methods.

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The development of an efficient and reliable multiple descriptions coding (MDC) scheme over lossy communication networks has been described. The advantage of MDC is that, if all the channels work, a high quality, possibly lossless, reconstruction can be achieved from all the received descriptions. On the other hand, a lower but still acceptable quality can be achieved if some of the channels are not received at all. In this article, a general framework of an efficient multiple description robust communication system with 2-and 4-channel cases is presented with a proposed block-based dc reallocation approach using intrinsic correlation. The peak signal-to-noise ratio (PSNR), mean squared error (MSE), bit rate, and entropy are calculated with the proposed method to analyze the reconstruction quality and the calculated results are compared with those of the other MDC methods. It is found that the proposed method, which uses an intrinsic correlation, gives comprehensive improvements over the other recently developed methods. KEY WORDS:Multiple description coding, nonhierarchical decomposition, block-based transform coding, discrete cosine transform. I. INTRODUCTIONMultiple description coding (MDC) [1-5] and reconstruction of images have received considerable attention in the signal processing community for the last few years because of its interesting and excellent properties over lossy communication networks such as internet, ATM networks, packet-switched networks, wireless communication networks over fading multipath channel and so on. With MDC, multiple descriptions (called bitstreams) are generated by splitting the input signal into multiple subsignals. The subsignals are then quantized and transmitted over the separate communication channels to the receiver. It is useful to apply the quantizer on the subsignal in transform domain rather than spatial domain. The decoder reconstructs the original signal from the received descriptions allowing lost bitstream(s) to be estimated from the received ones. The advantage of this system is that, if all the channels work, a high quality, possibly lossless, reconstruction is achievable from all the received descriptions. On the other hand, a lower but still acceptable quality can be achieved if some of the channels are lost at the decoder. In this article, the multiple description coding [3-5] for image transmission over unreliable communication networks (which cannot always guarantee the lossless data transmission) has been considered. A general framework of such a diversity system with an efficient and reliable MDC scheme with a simple approach (low complexity) is developed in this constraint. Here our special interest is the transmission of still images.

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