Patent ID: 8294947

Claim:
An image processing apparatus comprising: a first image reading unit configured to read image information of a front side of a document as an image signal; a second image reading unit configured to read image information of a back side of the document as an image signal; a specific-color specifying unit configured to specify a specific color by inputting an instruction at a specific position on the document; an outputting unit configured to generate and output a patch pattern that contains a first number of patches corresponding to color adjacent to the specified specific color and a second number of patches corresponding to color other than the color adjacent to the specified specific color, the first number of patches being larger than the second number of patches; and a color-difference correcting unit configured to correct a color difference between the image signal read by the first reading unit and the image signal read by the second reading unit based on a first image signal obtained by reading of the patch pattern performed by the first image reading unit and a second image signal obtained by reading of the patch pattern performed by the second image reading unit, wherein the outputting unit is configured to output the patch pattern corresponding to the color adjacent to the specific color in vicinity of a position corresponding to the position instructed by the specific-color specifying unit on the document.