| 摘要 |
PURPOSE:To compress picture data considerably by dividing a picture into square blocks of unequal size to encode it to data which is formed in a tree structure so that an average distortion in each block does not exceed an allowable value. CONSTITUTION:The input picture is encoded at every line through a line buffer 31 and a counting and luminance generating circuit 32 by a coding/decoding circuit 33. That is, the whole of the picture is divided from the highest level of 2<n>X2<n> blocks to the lowest level of 1X1 block (picture element), and the lowest level and the start block are set, and an average luminance and an average distortion are obtained, and 4 blocks are united into a block of the higher level if the average distortion is smaller than the allowable value. Picture blocks obtained in this manner are stored in a buffer 34 successively from the highest level. With respect to the first data block, the second and the third blocks of the highest level have luminance values X2 and X3, and blocks where a code ESC is stored are developed to the lower level and are stored in following data blocks. |
