| 摘要 |
PROBLEM TO BE SOLVED: To provide a watermark shift detection apparatus for detecting the shift of a watermark reading position in a watermark-embedded document. SOLUTION: The watermark shift detection apparatus is provided with: a watermark detection part 102 for detecting a first watermark signal matrix in which a plurality of watermark signals are arranged from an input image read from the watermark-embedded document 110, specifying the positions of respective watermark signals and detecting two or more pieces of information represented by the first watermark signal matrix; a watermark signal matrix restoration part 104 for restoring a second watermark signal matrix from information generated by using the two or more information; and a watermark shift calculation part 106 for comparing the first watermark signal matrix with the second watermark signal matrix and calculating the shift of respective watermark signal positions of the first watermark signal matrix which are specified by the watermark detection part 102 from respective watermark signal positions of the second watermark signal matrix. COPYRIGHT: (C)2009,JPO&INPIT
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