1. A copy-forgery-inhibited pattern image generation method in an image processing apparatus for generating a copy-forgery-inhibited pattern image including a latent-image part and background-image part, comprising: a step of determining a combination of a latent-image pattern which forms the latent-image part and a background pattern that forms the background-image part so that the latent-image part and background-image part have equal print densities; a step of inputting the determined latent-image pattern and background pattern, color information used to determine a color of the copy-forgery-inhibited pattern image, input image information as an image to be processed, copy-forgery-inhibited pattern basic information used to designate the latent-image part and background-image part, and camouflage region designation image information used to designate a camouflage region; and a step of generating the copy-forgery-inhibited pattern image on the basis of the input information.