| 摘要 |
PURPOSE:To stably form peculiar information on an image by changing the modulation amount of an overlap pattern an accordance with the value of an environment sensor at the time of overlapping peculiar information on an image forming device with the image of a specified color. CONSTITUTION:A luminance signal of the image is obtained in CCD 2105, and a LOG transform circuit 13 converts it into a density signal through an A/D conversion circuit 2106 and a shading circuit 2012. On the other hand, a machine number pattern generation circuit 2015 generates a pattern peculiar to the device and a modulation amount control circuit 2016 controls the modulation amount in the image signal only by yellow in accordance with a table corresponding to a water quantity mixed rate in air, which is calculated based on temperature/ humidity detected by the environment sensor 2010. The modulated pattern is synthesized by a comparator circuit overlapping the image signal. Namely, the pattern peculiar to the device can stably be formed on the image by making the added modulation amount to be much when an atmosphere has high temperature and high humidity. |
