Detection and correction of transmission errors in DPCM images

A new approach to detection and correction of transmission errors in DPCM images is proposed. Here each transmission error (streak noise) is detected via a sequence of the Wilcoxon-Mann-Whitney (WMW) rank-sum tests performed on a sliding window using four particularly designed grouping schemes. Instead of four possible patterns used by Kundu and Wu (1990), in the proposed approach 18 possible detection patterns represented as a decision tree are identified. The transmission error detection procedure is equivalent to tracing the decision tree. The estimated gray level shift of a detected streak noise is used to locate the streak origin. Then instead of using previous line replacement, each streak noise can be almost deleted by compensating the corrupted pixels with the estimated gray level shift. Experimental results show the feasibility of the proposed approach