| 摘要 |
PURPOSE:To compress an input picture at a fixed compressing ratio irrespective of the content of the input picture by comparing an input picture pattern with plural representative picture patterns stored in a memory beforehand and finding the closest representative pattern, and then, coding a high-frequency area by using the number indicating the representative pattern. CONSTITUTION:The pattern of orthogonally transformed picture data of several sheets of pictures selected as a training sequence in each block of a high-frequency area is stored in a code book as a model. A quantization circuit 14 for high-frequency component selects an output vector which gives the minimum distortion by comparing the pattern of an input vector with patterns of output vectors stored in the code book and outputs the index of the selected output vector. Then a coding circuit 15 for high frequency component outputs the index outputted from the circuit 14 after coding. Therefore, the picture quality and compressing ratio of vector quantization depend upon the number of the output vectors stored in the code book and the way of output vector selection. |
