Can JBIG2 compress a color image?
The short answer is yes, however, there are some issues. The JBIG2 Standard makes no reference to color image compression. JBIG2 is a 1-bit per pixel image compression standard. If a source image is partitioned into multiple 1-bit image planes and each plane is JBIG2 compressed then it is possible to compress a color image with the existing JBIG2 standard. SOC Robotics has added an Extension segment of type COLOR that supports this feature. The JBIG2 encoder encodes each plane of a multi-bit image as a separate JBIG2 page. The JBIG2 decoder if it finds an Extension Segment of type COLOR then re-assembles the individual pages into a color image. The source image may be a grey scale or color image. Color images with high frequency content such as a picture will not compress well using this technique as the bits in the higher bit planes becomes random. Computer generated color images such as line art, maps, etc can be losslessly compressed quite significantly using this technique.
