METHOD AND DEVICE FOR FORMING COLOR IMAGE

摘要

PROBLEM TO BE SOLVED: To clarify that a color image is a copied image by adding a specific pattern which cannot be discriminated by human eyes but can be identified by an identification means to the color image recorded in a recording medium with respect to a copying machine or the like. SOLUTION: A post processing part 125 in a picture processor 120 converts RGB color picture data into YMCK color picture data. An additional color forming device 140 calculates the color data YaMaCaKa of a specific pattern obtained from a specific pattern generator 130 on the basis of the RGB color picture data. A synthesizer 150 synthesizes the YMCK color picture data and the color data YaMaCaKa of the specific pattern and generates Y'M'C'K' color picture data to be output color picture data including the data of the specific pattern. An image output device 210 adds the specific pattern to the color image on the basis of the Y'M'C'K' color picture data.