Color variation specification method and a device therefor

Abstract

The present invention relates to a method and device for the determination of restricted colors by a means where, for example, image data displayed by means of approximately 16,000,000 colors is displayed in terms of a restricted number of colors. For example, in the case of 256 colors, an image is displayed in more natural colors. Furthermore, the present invention relates to a method and a device for the prevention of the generation of pseudo color contouring by means of specifying, in advance, portions in which the color variation is loose from the periodicity of the values appearing in the subordinate bits of each picture element at the time of the specification of display colors, and allocating a large number of display colors to portions having loose color variation. In addition, the present invention relates to a method and device which, by means of disposing each picture element of the image data in a uniform color space and conducting a discriminant analysis with respect to the distribution of the picture elements in this color space, determines ranking numbers with respect to the coordinate axes of the chromaticity component of the uniform color space and ranking numbers with respect to the coordinate axis of the brightness component in accordance with the distribution of the colors of the image data at the time of the restriction of the display colors, and thus determines the representative colors.