A Parallel Decoder for Lossless Image Compression by Block Matching

A work-optimal O(lognlogM) time PRAM-EREW algorithm for lossless image compression by block matching was shown in L. Cinque et al., (2003), where n is the size of the image and M is the maximum size of the match. The design of a parallel decoder was left as an open problem. By slightly modifying the parallel encoder, in this paper we show how to implement the decoder in O(lognlogM) time with O(n/logn) processors on the PRAM-EREW. With the realistic assumption that the size of the compressed image is O(n
^1/2
), the parallel decoder requires O(log
²
n) time and O(n/logn) processors on the mesh of trees