| 摘要 |
PROBLEM TO BE SOLVED: To faithfully extract watermark information from text images even if position information of a character and a row in the text images into which watermark information is embedded is uncertain due to noise and distortion. SOLUTION: In the text images where character strings are arranged in the respective rows, bit strings embedded in the respective rows are extracted (S403) from the embedded text images obtained by embedding the embedded bit strings where a plurality of pieces of watermark information are connected by the number of bits, which corresponds to the number of the character strings in the respective rows. A value of the bit in the position in the embedded bit string is decided (S404) by referring to respective values of bit groups positioned in the same bit position in the respective bit strings extracted from the respective rows. The values of the respective bits of the bit strings constituting watermark information, which are included in a set of the values of the bits decided in a plurality of the bit positions, are decided and outputted (S405). COPYRIGHT: (C)2004,JPO&NCIPI |
