| 摘要 |
PROBLEM TO BE SOLVED: To prepare picture data with a watermark expressing a color picture with a watermark by converting color picture data of a first color system to a second color system and inverting color picture data of the obtained second color system to the first color system through the use of an inversion matrix. SOLUTION: In embedding a watermark to an original picture P, a mark picture M including a watermark to be embedded is prepared in addition to this picture P. This picture M is a binary picture and is converted from an RGB color system to a YCbCr color system first. A pixel at a position equivalent to the effective area of the watermark is converted by using an embedding conversion matrix obtained by adding an original conversion matrix and a watermark matrix. At the time of executing it concerning all the pixels, YCbCr picture data F with a watermark embedded with a digital watermark is obtained. At the time of operating an inversion matrix with respect to this YCbCr picture data F with watermark, RGB picture data P, with a watermark are obtained. |
