Background pattern image generation device, background pattern image generating method, additional information reading device, additional information reading method

摘要

PPROBLEM TO BE SOLVED: To output printed matter having the same effect as that of a false image preventive paper sheet by using a plain paper sheet without using the paper sheet to which special printing is applied such as a false image preventive paper sheet. PSOLUTION: A ground tint image generating part 11 generates a new image I1 by representing a latent image territory by a set of dots expressed by the first number of pigments and by representing a background area by the set of dots expressed by the second number of pigments being different from the first number of pigments. Then, an image additional part 12 generates an image I2 by controlling each position of the set of dots contained in the latent image area and/or the background area of the image I1 according to a value of a bit at the corresponding bit position of additional information. PCOPYRIGHT: (C)2004,JPO&NCIPI