PICTURE COMPRESSION CODER

摘要

PURPOSE:To obtain desired picture quality or stable picture quality. CONSTITUTION:When an input picture Si is inputted to a statistic quantity arithmetic operation means 21 and an information quantity compression means 11, the means 21 detects the statistic quantity S21 of the input Si to give it to an S/N prediction means 23. The means 11 excludes the redundancy of the input Si and gives the resulting picture data S11 to a quantization means 12 and a quantization error measurement means 22. The means 12 quantizes the S11 and gives its quantization output data S12 to a coding means 13 and the means 22. The means 13 codes the S12. The means 22 measures a quantized error power S22 from the input output picture data of the quantization means 12 and gives it to the means 23. The means 23 predicts the relation between the S/N of the compressed picture and the quantization step width from the S21, S22 to control the quantization step width in the means 12 so that the compression S/N (picture quality) satisfies an external request SI.