| 摘要 |
PURPOSE:To attain quantization matching the 4 characteristic of a picture when picture data subject to orthogonal transformation is quantized. CONSTITUTION:A block activity calculation section 108 obtains a degree of a high frequency component included in each block, that is, a block activity from picture data subject to block processing. An evaluation function generating section 110 obtains an evaluation function such as a variance from the block activity of plural blocks and gives the result to a quantization table setting section 116. A total activity calculation section 112 obtains a total activity and gives it to the setting section 116. The quantization table setting section 116 selects a quantization coefficient based on both the evaluation function representing a characteristic of the picture and the entire characteristic of the picture and sets the result to a quantization section 104. Thus, even when the picture has the same value of the total activity but the distribution of the high frequency component differs, the quantization is executed by a different quantization coefficient and then the quantization matching the picture characteristic is executed. |
