| 摘要 |
PURPOSE:To reduce average encoding-distortion without causing a large degree of deterioration in the quality of a picture by providing two stages of quantization processes which are vector quantization and a scalar quantization processes, and controlling the number of bits to be allocated to the scalar quantization in the second stage. CONSTITUTION:A representative vector that is closest to a significant block selected by a significant block detecting circuit 8 that is a picture block to be encoding-transmitted, is selected by a vector quantizer 9, and a vector- quantization error is obtained by a subtraction circuit 10. From such an error signal, an in-block error signal power is calculated by a vector-quantization error calculation circuit 11. From the result of the above calculation and the state of the information-storing quantity of a buffer memory 18, an encoding control circuit 12 determines the quantity of codes allocated to a block currently encoded and a bit-distribution table used to distribute the said quantity of codes to respective picture elements in the said block. In a scalar quantizer 13, the vector-quantization error signal is quantized, and outputted through a multiplexing circuit 17 and the buffer memory 18. |
