| 摘要 |
PURPOSE:To prevent deterioration of a picture by deciding a block that is decided to be inclusive of an edge therein to be a block that includes the edge of a color line image if there is a correlation between its luminance information and saturation information. CONSTITUTION:In the case the maximum color difference DELTAd in a block is larger than a threshold value d0, the block is decided to be a color edge block, and a comparator 122 output '1'. A polar coordinate transformer 131 transforms chromaticity signals a*, b* to amounts theta*, r* corresponding to hue and chromaticness, and a maximum phase difference arithmetic unit 134 outputs the maximum value DELTAtheta of the hue difference of respective picture elements. The value is compared with a threshold value thetaT in a comparator 135, and '1' is outputted when the thetaT is larger, and this output is AND-operated with a color edge decision signal E1 in an AND circuit 136. A decision signal Ecode comes into '1' clock includes a color edge and constituted of a chromatic color and an achromatic color. As a result, a color edge constituting a color character can be separated from other color edge parts, and an appropriate processing can be applied to it, to obtain an excellent result of an image processing. |
