| 摘要 |
<p>PURPOSE:To remove block distortion without the occurrence of an out-of-focus image, etc. CONSTITUTION:Output data of a reverse quantization circuit 12 is divided into two and one of them obtains the image signal of actual space in a reverse orthogonal transformation circuit 13. An absolute value in the space frequency component of the other one is compared with a threshold by a coefficient decision circuit 14 at every block so that information of a coefficient which is larger than the threshold is transmitted to a distortion removing characteristic deciding circuit 17 as the singnificant coefficient. The output image signal of the reverse orthogonal transformation circuit 13 is decomposed so as to be a sub-block in a sub-blocking circuit 15 and, then, executed an optimum distortion removing processing at every sub-block. That is, distortion removal is processed by low pass characteristic which is decided by a distortion removing characteristic deciding circuit 17 and which preserve a significant coefficient band in the block of a compression unit, which is obtained by the coefficient decision circuit 14 when the distortion removing processing is execute by the sub-block unit.</p> |
