| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that the extraction of an electronic water mark is also carried out from an area where the electronic watermark is not embedded and the reliability of the extracted electronic watermark is degraded when the electronic watermark is extracted from an entire image including a blank space produced in the process of image read operation or an area produced by correction of geometrical conversion. SOLUTION: An image processor is provided with a parallel translation extent calculation part 702 which uses a positioning signal to calculate an extent of parallel translation applied to the image, a parallel translation correction part 1301 which generates a corrected image obtained by correcting the extent of parallel translation calculated by the parallel translation extent calculation part 702, an effective area discrimination part 1302 which discriminates the effective area where the existence of electronic watermark is discriminated, and an additional information extraction part 703 which extracts the electronic watermark from the effective area discriminated by the effective area discrimination part 1302. |
