| 摘要 |
PURPOSE:To provide a picture compression device provided with a means deciding an optimum quantization step for the quantization based on the statistical property of a picture, and further by considering the visual characteristic of humans. CONSTITUTION:By an orthogonal transformation means 1, the block orthogonal transformation of a picture is performed and the standard deviation and dispersion of each frequency component are determined by a dispersion arithmetic means 3. In a quantization characteristic table 6, the relation between a normalization quantization step width and normalization quantization error power are stored. By a quantization step decision means 4, the normalization quantization error power is determined so that quantization error power shown by the product of the square of the visual characteristic value stored in a visual characteristic table 5, the dispersion and the normalization quantization error power may be a prescribed value (quantization factor), the corresponding normalization quantization step width is determined by the quantization characteristic table 6 and the product of this normalization quantization step width and the standard deviation is defined as an optinum quantization step width. |
