| 摘要 |
PROBLEM TO BE SOLVED: To add a mark to a color original without deteriorating the readability of original information by discriminating an image background area from the density of image data and compositing the fixed color mark image data with an image, i.e., a background area. SOLUTION: A mark area detection circuit 40 produces a mark area signal from the R, G and B image data. A white background image is decided if the R, G and B value are larger than each threshold and the mark area signal is set at 'H' Otherwise, a certain type of image data is decided and the mark area signal is set at 'L'. A mark adding circuit 80 stores a secret holding mark such as a numeric character of a serial number and then outputs the mark together with a setting enable color when the mark data are set at 'H'. When both mark area signal and mark data are set at 'H', the secret holding mark outputted from the circuit 80 is synthesized with the background image. When the mark area signal or the mark data are set at 'L', the input image data are outputted as they are. |
