| 摘要 |
Original image data obtained by reading an original is joined with watermark data associated with a watermark for copy control, which appears as a result of making a copy. The watermark generating section sets the spatial frequency of a chromatic halftone pattern of a foreground, which appears as a result of making a copy, lower than the spatial frequency of an achromatic halftone pattern of a foreground, which appears as a result of making a copy. Accordingly, it becomes more difficult to recognize a foreground in an original document when the foreground is generated using an achromatic color, while a foreground in the duplication is recognized clearly when the foreground is generated using a chromatic color. |
