| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem that a satisfactory reduction effect for block noise is not obtained for a video signal having an image portion with a gradual tone change such as gradation, since reduction processing of block noise is performed conventionally by a filter circuit. <P>SOLUTION: A block noise level difference calculation circuit 12 calculates an intermediate value a of a level difference A between rectangle blocks at a block boundary line to be observed and an intermediate value b of a level difference B between rectangle blocks at an adjacent block boundary line, respectively. A correction circuit 11 outputs a video signal obtained by adding a video signal before block noise reduction to each value of which the pixel level of each pixel is aligned on a straight line connecting the intermediate value a to the intermediate value b, on the basis of the intermediate values a and b. Thereby, the correction circuit 11 outputs a video signal with sufficiently reduced block noise even for a video signal having an image portion with gradual tone change such as gradation. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
