| 摘要 |
A pixel which is one pixel prior to a pixel to be coded x in image data is defined as a specific pixel a, and differences (b-a) and (c-a) between each of pixel data of neighboring pixels b and c and pixel data of the specific pixel a are calculated. The differences (b-a) and (c-a) are compared to a predetermined value Th1, and if both of the differences (b-a) and (c-a) are less than the predetermined value Th1, a difference (x-a) between pixel data of the pixel to be coded and the pixel data of the specific pixel is encoded by Markov model coding on the basis of the difference (x-a) and the differences (b-a) and (c-a). Whereas, if at least one of the differences (b-a) and (c-a) is not less than the predetermined value Th1, then the pixel to be coded is encoded by predictive coding on the basis of an average of the pixel data of the specific pixel a and the neighboring pixel b, {(a+b)/2} and an error of the average with respect to the actual pixel data of the pixel to be coded x.
|
