| 摘要 |
PROBLEM TO BE SOLVED: To provide an electronic information embedding method, apparatus used for embedding electronic information, and to provide a program in which the original random point group data can be prevented from being illegally used. SOLUTION: In embedding as electronic watermark data into point group data obtained in response to a three-dimensional measurement, an x-y plane area specifying the point group data is divided into predetermined small areas, a group of points included in each small area is generated and for each group of points, (x) and (y) coordinate values thereof are transformed into a group of offset points so that the center of gravity of the group of points becomes an origin. Discrete Fourier transform is performed for each group of points to determine a Fourier coefficient sequence, and the coefficient sequence is changed in accordance with the electronic watermark data to define a watermarked Fourier coefficient sequence. Inverse discrete Fourier transform is performed on the watermarked Fourier coefficient sequence to generate a watermarked complex number sequence and regarding the watermarked complex number sequence, an optimal watermarking strength is determined to satisfy tolerance of a coordinate value error caused by embedding. Inverse offset is then performed on the watermarked Fourier coefficient sequence to define watermarked point group data. COPYRIGHT: (C)2007,JPO&INPIT
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