Detection and concealment of transmission errors in MPEG-2 images - A genetic algorithm approach

In this paper, the detection and concealment approach to transmission error s in MPEG-2 images using genetic algorithms (GA's) is proposed. For entropy -coded MPEG-2 images, a transmission error in a codeword will not only affe ct the underlying codeword but also may affect subsequent codewords, result ing in a great degradation of the received images. Here, a transmission err or maybe a single-bit error or a burst error, The objective of the proposed approach is to recover high-quality MPEG-2 images from the corresponding c orrupted MPEG-2 images without increasing the transmission bit rate, In the proposed error-detection approach, by using the constraints imposed on compressed image data, all the slices within an MPEG-2 picture can be co rrectly located, After a slice is located, similar to Chu and Leou [22], tr ansmission errors within the slice are detected by two successive procedure s: 1) whether the slice is corrupted or not is determined by checking a set of error-detection conditions under decoding and 2) the precise location ( block-based) of the first transmission error (i.e., the first corrupted blo ck) within the corrupted slice is located by a block-based backtracking pro cedure. For a corrupted block, the proposed GA approach to error concealmen t is employed to conceal the corrupted block by iteratively performing repr oduction/crossover/mutation operations and evaluating the proposed fitness function until the stopping criterion is satisfied. Based on the simulation results obtained in this study, the proposed approach can recover high-qua lity MPEG-2 images from the corresponding corrupted images up to a bit erro r rate of 0.5%.