| 摘要 |
PURPOSE:To encode a block much contributing to picture quality with priority by classifying a block of an original picture into plural blocks depending on the degree of its gradation change and coding each group sequentially. CONSTITUTION:Picture data by one block from a buffer 211 are sequentially inputted via a block buffer 236 to one of input terminals of a multiplexer MPX 235 and the output of an in valid block generating means 113 is inputted to the other terminal. In this case, a characteristic value is calculated in parallel with the data input to the buffer 236 and when data by one block are latched in the buffer 236, the result of comparison corresponding to the block is inputted to the MPX 235. The MPX 235 selects an invalid block depending on the result of comparison representing it that the characteristic value is a threshold level T or below, and sends the selected block sequentially to a buffer 237, then picture data by one pattern comprising blocks with a rapid gradation change and invalid blocks are edited again in the buffer 237. Thus, a sharp decoded picture is obtained. |
