抄録
This paper presents a method for encoding and decoding images, especially medical images with the optimization of probability of cross points which are neighbor to the points of gray levels 2n. The base of this statement was presented in papers of the authors that proposed the effect of Gray coding on cross points. At first the effect of Gray codes is determined with an adjacent data set because of the characteristic of images being that the data do not change much in a specific area, then this effect is generalized with real data without losing the generality for their statistical characteristics, espescially in medical images which have many regions with the same gray scale. This effect makes bit states of cross points change from original data bits, so the probabilities of data bits on specific bit planes in cross point regions and then the entropies of messages are changed. These probabilities and entropies are estimated and compared with the probabilities and entropies of original data bits. This change of probability has important effects on encoding and decoding processes of lossless medical image compression.
