Patent ID: 8587606

Claim:
An apparatus for processing an input image, comprising: a first extraction unit configured to classify pixels of the input image into a plurality of groups, all hues of the pixels being classified to the plurality of groups, each respective pixel of the pixels being classified to one of the groups of which classified hues include a hue of the respective pixel, and to extract a first group of which the number of classified pixels is largest among the plurality of groups; a second extraction unit configured to extract a specific number of pixels as a second group in order of larger distance from a reference axis on a plane defined by a chroma axis and a luminance axis crossing the reference axis, from the first group; a first transform unit configured to execute a plurality of color-transform processing to the second group, and to obtain a plurality of third groups of pixels, each third group being the second group transformed by each color-transform processing; a reliability calculation unit configured to calculate a reliability of each third group, the reliability being larger when pixels of the third group being more located in shape of a straight line on the plane; a selection unit configured to select a color-transform processing by which the third group has the largest reliability, from the plurality of color-transform processing; and a second transform unit configured to execute the color-transform processing to the input image to obtain an output image.