| 摘要 |
<p>PROBLEM TO BE SOLVED: To make a tile boundary hardly visible by reducing quantization rate in a region in the vicinity of the tile boundary which is generated, when an image is divided into tiles and compressed images obtained by performing high compression for each tile decoded. SOLUTION: A square tile is designated by an arbitrary size to an image, the image is divided by using the designated square tiles, and the square tiles in which the image is divided are decomposed into bit planes by each tile. The decomposed bit planes are ordered from MSB to LSB according to coding order, and layers, e.g. from the most significant layer 0 to the least significant layer 9 are constituted by using the ordered bit planes. Bit planes of code blocks 2, 3; 6, 7; 10, 11 in a region in the vicinity of the tile boundary, in which region the quantizing rate is suppressed to be relatively low are shifted, so as to be included in a higher rank layer side to bit planes of code blocks 0, 1; 4, 5; 8, 9 in a region distant from the tile boundary in which region the quantizing rate is maintained to be relatively high, and the quantizing rate is reduced.</p> |
