Speeding up Lossless Image Compression: Experimental Results on a Parallel Machine

Arithmetic encoders enable the best compressors both for bi-level images (JBIG) and for grey scale and color images (CALIC), but they are often ruled out because too complex. The compression gap between simpler techniques and state of the art compressors can be significant. Storer extended dictionary text compression to bi-level images to avoid arithmetic encoders (BLOCK MATCHING), achieving 70 percent of the compression of JBIG1 on the CCITT bi-level image test set. We were able to partition an image into up to a hundred areas and to apply the BLOCK MATCHING heuristic independently to each area with no loss of compression effectiveness