Patent ID: 7577271

Claim:
An image processing apparatus which forms synthesized image information having sub-information embedded in an invisible state in main image information, comprising: a plurality of color-difference amount correction processing sections which subject main image information to color-difference correction processes by use of color-difference amounts previously set therein, a plurality of color-difference modulation processing sections which correspond in number to the color-difference amount correction processing sections and perform color-difference modulating processes based on a plurality of key information items and a plurality of color-difference amounts corrected by the plurality of color-difference amount correction processing sections, wherein each key information is image information configured by black and white pixels, wherein each color-difference modulation processing section allocates first and second colors set in a complementary color relation to white and black pixels of the key information, respectively, a synthesis processing section which selects a plurality of image information items subjected to color-difference modulation by the plurality of color-difference modulation processing sections based on the sub-information and synthesizes the selected image information items, wherein the synthesis processing section performs a selecting and synthesizing process to set the number of connecting pixels of the first color and connecting pixels of the second color to a minimum number in image information obtained by selecting and synthesizing a plurality of image information items subjected to color-difference modulation by the plurality of color-difference modulation processing sections, and a superposition processing section which superposes image information as sub-information synthesized by the synthesis processing section on the main image information.