Binary Image Compression via Monochromatic Pattern Substitution: A Sequential Speed-Up

A method for compressing binary images is monochromatic pattern substitution. Monochromatic rectangles inside the image are detected and compressed by a variable length code. Such method has no relevant loss of compression effectiveness if the image is partitioned into up to a thousand blocks and each block is compressed independently. Therefore, it can be implemented in parallel on both small and large scale arrays of processors with distributed memory and no interconnections. We show in this paper that such method has a speed-up if applied sequentially to the partitioned image. Experimental results show that the speed-up happens if the image is partitioned into up to 256 blocks and sequentially each block is compressed independently. It follows that the sequential speed-up can also be applied to a parallel implementation on a small scale system.