Patent ID: 7339599

Claim:
An image processing apparatus comprising: inputting means for inputting area-assignment information that defines latent-image area and background area and binary additional information composed of a sequence of bit values (0 or 1); determination means for determining a plurality of positions in the background area which is defined by the area-assignment information and a plurality of positions in the latent-image area which is defined by the area-assignment information; generating means for generating patterned image data by arranging first dots of a first dot size at the determined positions in the background area and arranging second dots of a second dot size that is a smaller dot size than the first dot size at the determined positions in the latent-image area, the first dots being easily reproducible when copied and the second dots not being easily reproducible when copied; and information-attaching means for attaching the binary additional information to at least the latent image area by moving at least the arranged second dots such that it can be determined whether an image on a printed material is an original because the binary additional information can be extracted from the original image based on the positions of the moved second dots and predetermined positions in the latent-image area, and the binary additional information cannot be extracted from a copy, the information-attaching means moving each second dot from the predetermined position along a direction which is defined by a bit value at a corresponding bit position in the sequence of bit values (0 or 1) of the binary additional information.