| 摘要 |
PURPOSE:To lower the dependence of the size of data on input image data by comparing designated size with the size of outputted data and changing quantization table data so as to reduce difference between them. CONSTITUTION:When the first compression is completed, a compressed data controller 8 compares designated size data stored in a designated size storage device 7 with compression data size stored in a compressed data storage device 6. When the compressed data size is larger than the designated size, quantization table data stored in a quantization table storage device 4 is set at a large numeric value, adversely, when the former is smaller than the latter, the quantization table data is set at a small numeric value. After that, the second encoding is applied to conversion code data stored in a conversion code data storage device 2 by a quantizer 3 and a variable length encoder 5, and compressed data is stored in the device 6. A compression operation is completed when the compressed data size nearly approaches the designated size. |
