Patent ID: 7903888
Filing Date: 2011-03-08
Classification: H04N

Abstract:
1. An image encoding apparatus comprising: a processor programmed to control: an input unit adapted to input multi-valued image data by block constituted by plural pixels; an identification information generation unit adapted to classify respective pixels within an input block into first and second groups in correspondence with respective pixel values, and generate identification information to identify groups of the respective pixels; a calculating unit adapted to calculate an average value of pixels belonging to said first group, an average value of pixels belonging to said second group, and a differential value between said two average values; a substituting unit adapted to add said differential value to respective pixels belonging to said first group or subtract said differential value from the respective pixels belonging to said first group, so as to reduce a difference between the average value of said first group and the average value of said second group, thereby substitute pixel values belonging to said first group; and an encoding unit adapted to encode respective pixel values in the block after substitution, said differential value and said identification information, and output encoded data of block of interest.