Cross-point regions on multiple bit planes for lossless images compression

Abstract

This study presents cross-point regions for lossless image compression on multiple bit planes (CRICM), an algorithm for losslessly encoding and decoding images, especially medical images, by optimising on the probability of bits on different bit planes of cross points that are neighbour points of grey levels 2n. Based on Gray coding, Gray codes of cross points are determined on an adjacent data set because images characteristically contain data that do not change much in a specific area, then this effect is generalised for real data without losing generality for their statistical properties. This is especially true for medical images that have many regions with the same grey levels. The Gray code transformation makes the bit states of cross points change from the original data bits, so firstly the probabilities of data bits on specific bit planes in cross-point regions and then the entropies of the messages are changed. These probabilities are estimated and compared with the probabilities of the original data bits. This change of probability has important effects on the encoding and decoding processes in lossless medical image compression.