| 摘要 |
PURPOSE:To reduce the distortion of a block, to reproduce the picture of high picture quality and to eliminate the necessity of a large capacity memory by detecting a contour part from picture data before orthogonal transform, determining the allocation of information quantity and making the allocation of the information quantity large to the block where the contour part exists. CONSTITUTION:The picture data are read out of a picture memory 26 for the unit of block and a DC(direct current) component is extracted by a DC component extraction circuit 27. Parallelly with the processing, a parameter to determine a normalization factor and bit distribution is extracted and data, for which the orthogonal transform of the picture data is executed by an orthogonal transform circuit 40, are normalized by a normalization circuit 41 and quantized by a quantization circuit 42 based on a bit number calculated by a bit distribution circuit 36. The activity of each sub block is weighted according to the height of edge and the bit distribution is executed so as to be proportional with the activity. Thus, the distortion of the block is reduced and the picture of the high picture quality can be reproduced. Then, the necessity of the large capacity memory can be eliminated. |
