| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect striped level difference to be generated in a gradation area in a displayed image resulting from roughness of quantization of a video signal. <P>SOLUTION: Pixel values of two adjacent pixels of the video signal are sequentially compared by a horizontal pixel value comparator circuit A11, an area in which difference of the pixel values compared by the comparator circuit A11 is within a fixed range is detected as a horizontal flat area by a horizontal detection circuit A15, a boundary of the detected area in the horizontal direction is computed, when difference or a degree (inclination) of change of pixel values before and after the boundary is within a specified range, the boundary is decided as the level difference in the gradation area. Similarly, pixel values of two pixels arranged in the perpendicular direction of the video signal are sequentially compared by a perpendicular pixel value comparator circuit A12, a perpendicular flat area is detected from a comparison result of the comparator circuit A12 by a perpendicular detection circuit A16, a boundary of the detection area in the perpendicular direction is computed and whether or not the boundary is the level difference within the gradation area is decided from difference or a degree (inclination) of change of pixel values before and after the boundary. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
