| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration in the image quality regardless of a transmission bit rate by detecting a motion vector by a 1st pre-filtering processing and applying coding processing toe a dynamic image signal with a 2nd pre- filtering processing. SOLUTION: Pre-filters 101, 102 each has a time filter and a spatial filter and the characteristic of the filters is changed depending on a finness of a pattern, a motion speed of the image, contrast of luminance and a transmission bit rate from a characteristic quantity detector 110. An image signal processed by the pre-filter 102 is given to an ME deice 105, from which a motion vector signal is obtained. A hybrid coder 104 conducts motion compensation inter-frame prediction from the motion vector signal and an output of the pre-filter 101 and conducts conversion coding such as DCT for a predicted error. Thus, mis- detection of the motion vector is prevented, the deterioration in the image quality is minimized and a sense of mass of grain noise is left. |
