| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To encode an entire image at a high compression rate while preventing degradation of reproduced image quality by properly switching reversible encoding and non-reversible encoding by pixel block units. <P>SOLUTION: An input image data is divided into tiles of a predetermined size in a block division unit 102. A valid level number counter unit 104 counts the number of brightness levels of each color component appeared in the target tile (the number of valid levels). The input tile is encoded in a tile data reversible encoding unit 108 and a tile data non-reversible encoding unit 114, respectively. A selector 115 generates a weighting factor in accordance with if the number of valid levels of all the color components in the target tile satisfies a predetermined condition, compares a data quantity encoded by reversible encoded and that encoded by non-reversible encoding by using the weighting factor, selects the smaller encoded data quantity, and outputs. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
