| 摘要 |
PROBLEM TO BE SOLVED: To provide an image processing method capable of embedding sub-information into even any kind of a multi-tone image certainly without causing deterioration in image quality, and improving prevention against the counterfeiting or alteration of a printed matter. SOLUTION: At an image processing applied to a multi-tone image on a printed matter inputted by an image input portion such as a camera, the tone correction (first processing) of the multi-tone image for characteristics c shown in Fig. 4 is applied as pre-processing to the multi-tone image inputted by the image input portion. Sub-information in an invisible status is embedded into the multi-tone image applied with the tone correction for the characteristics c. Tone correction inverse to the pre-processing, that is, tone correction (second processing) for characteristics a shown in Fig. 4 is applied to the multi-tone image embedded with the sub-information as post-processing. COPYRIGHT: (C)2006,JPO&NCIPI
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