| 摘要 |
PROBLEM TO BE SOLVED: To improve quality in a picture to be restored from a signal which is generated by compression encoding. SOLUTION: An input picture signal I restored from a compression picture signal is made into a block. A DCT(discrete cosine transformation) transforming circuit 32 creates a DCT coefficient value based on the signal which is made into a block. The value where a space frequency is in a middle area and a high area is extracted among the DCT coefficient ones and dispersion values are calculated based on them. When at least one of the dispersion values is smaller than a first threshold, a first flag is flagged. In the meantime, an adjacent pixel extracting memory 33 extracts the group of pixels being adjacent across a block boundary. A differential absolute value between the pixels is calculated and the number of times where the calculated value continuously becomes larger than the second threshold is counted by a continuity counting circuit 43. When the counted value is larger than the third threshold, the third flag is flagged. When the first and the third flags are simultaneously flagged, the fourth flag indicating the position of a block distortion is flagged. |
