| 摘要 |
PROBLEM TO BE SOLVED: To efficiently encode a component of an image signal. SOLUTION: In dynamic range detecting parts 23R, 23G and 23B, respective maximum and minimum values of R, G and B components which constitute a component signal in pixels in a prescribed block are detected, and dynamic ranges DRR, DRG and DRB which are finite differences between the maximum and minimum values are calculated. Furthermore, in a maximum detecting part 24, a block dynamic range BDR which is the maximum value among the ranges DRR, DRG and DRB, is detected and common quantization step width ▵which quantizes the R, G and B components, based on the range BDR, is decided. Then, the R, G and B components are separately quantized according to the width ▵ in quantizers 27R, 27G and 27B. |
