| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an image compression coding and image compression decoding device in which a frequency characteristic and a distortion characteristic of an output image after companding processing are controlled. SOLUTION: The device has a compression processing section 1 and an expansion processing section 5. On the other hand, the compression processing section 1 has a DCT transformation circuit 2, a quantization circuit 3 and a variable length coding circuit 4. The expansion processing section 5 has a variable length decoding circuit 6, an inverse quantization circuit 7, and a DCT inverse transformation circuit 8. A 1st quantization matrix M1 used for quantization of the compression processing section 1 differs from a 2nd quantization matrix M2 used for quantization of the expansion processing section 5. That is, the compression processing section 1 uses the 1st quantization matrix M1 in which a gradient in increase from low to high frequencies is higher and the expansion processing section ruses a 2nd quantization matrix M2 with a flat increase.</p> |
