ELECTRONIC WATERMARK INSERTING METHOD, ELECTRONIC WATERMARK INSERTING APPARATUS, ELECTRONIC WATERMARK INSERTING PROGRAM, ELECTRONIC WATERMARK DETECTING METHOD, ELECTRONIC WATERMARK DETECTING APPARATUS AND ELECTRONIC WATERMARK DETECTING PROGRAM

摘要

PROBLEM TO BE SOLVED: To detect data which are embedded in the form of an electronic watermark on a card read by an image scanner with high error immunity. SOLUTION: In a frequency domain, a rotating angle is detected by points A, B, C and D and positions 1-1 to 1-10 are corrected by the rotating angle. By making a majority decision among values of positions of the same number in three circles, values of respective bits are determined and an error is detected according to whether or not the number of bits of "1" is a predetermined number. COPYRIGHT: (C)2006,JPO&NCIPI