| 摘要 |
PROBLEM TO BE SOLVED: To set a proper error correction code in consideration of errors due to printing and scanning during extraction of embedded information by operating character spacing and making an error correction code of watermark information to embed it. SOLUTION: An error rate calculation part 104 estimates an error rate of an electronic document in accordance with information of the accurate number of characters and their placement positions, which are obtained by analyzing the electronic document and the number of characters and their placement positions shown by character images extracted from a document image generated from the electronic document. An error correction coding parameter determination part 107 determines an error correction coding parameter on the basis of the error rate and watermark information. A watermark information embedding part 108 adjusts a description indicating the placement positions of characters of the electronic document in accordance with coded data generated by the determined error correction coding parameter, to perform embedding processing using character spacing. COPYRIGHT: (C)2011,JPO&INPIT
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