| 摘要 |
PURPOSE:To reduce the required amount of transmission data of quantization bits generated at every block. CONSTITUTION:The dynamic range DR of the block that is the difference of the maximum value MAX and the minimum value MIN is found at a subtraction circuit 7. A quantization step width generation circuit 9 generates quantization step width suitable for the dynamic range. Each image data from which the minimum value MIN is eliminated is quantized at a quantization circuit 11 with the quantization step width DELTA, and for example, a code signal DT of constant four bits is generated. Four sub blocks are formed by dividing one block. A comparator 13 compares the dynamic range DR' of the sub block with a threshold value TH-P, and generates an ID flag. The ID flag is supplied to a data conversion circuit 12, and in the sub block whose DR' is smaller than the threshold value TH-P, one representative code is generated from the data conversion circuit 12. |
