An improved technique for compressing a color or gray scale pixel map
representing a document using an MRC format including a method of
segmenting an original pixel map into two planes, and then compressing the
data or each plane in an efficient manner. The image is segmented such
that pixels that compress well under a lossy compression technique are
placed on one plane and pixels that must be compressed losslessly are
placed on another plane. Lossy compression is then applied to the lossy
pixel plane while lossless compression is applied to the lossless pixel
plane.