It is a segmentation based coding which enables the user to separate foreground from background, and more specifically, text regions from non-text regionsJPEG2000 is that, although an algorithm for segmenting color images is not specified, the JPEG2000 spec does support segmentation-based coding. In fact, the most effective rates for color compression are obtained by analyzing, understanding, and reversing the page layout process. It becomes important in JP2 segmentation-based coding. JPEG 2000 is a wavelet-based image compression standard. It was created by the Joint Photographic Experts Group committee in the year 2000 with the intention of superseding their original based JPEG standard .
JPEG's indifferent behaviour
Unlike many OCR systems, which can "tolerate" missing text regions that are not aligned horizontally or vertically, color compression using Mixed Raster Content (MRC) coding or based on JPEG2000 part 6, is much less forgiving. The basis of MRC coding is separating out the high frequency signal information from the low frequency information. Usually, the high frequency information in an image is text-related. Of course, there is also line art, edge structures, and other objects that may degrade when kept at low resolution. But text regions must be recognized and lifted for MRC-based compression to be non-degrading. This necessitates finding all text regions, regardless of skew, rotation, etc.
Features of JPEG200
Superior compression performance: At high bit rates, where artifacts become nearly imperceptible, JPEG 2000 has a small machine-measured fidelity advantage over JPEG. At lower bit rates (e.g., less than 0.25 bits/pixel for gray-scale images), JPEG 2000 has a much more significant advantage over certain modes of JPEG: artifacts are less visible and there is almost no blocking. The compression gains over JPEG are attributed to transparency and alpha planes, and JPEG2000 is robust to bit errors introduced by noisy communication channels, due to the coding of data in relatively small independent blocks.