| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for inserting hardly detectable watermark data to the signals of video images and sound, etc., and the detection method. SOLUTION: A conversion processing means 1 for frequency converting input signals and a pseudo random number generation means 21 for deciding the insertion position of the watermark data are provided. The input signals are transformed to two-dimensional frequency components by using a wavelet transformation means 11 and a pseudo random number PNij is multiplied to the transformation coefficient Bi corresponding to a frequency and an amplitude. The multiplied result bi is inputted to a weighted addition means 23 and the watermark data Wj are added. The signals xi to which the watermark data are inserted and the signals ri to which the watermark data are not inserted generated in a subtraction means 24 are inputted to an inverse transformation processing means 3 and inversely wavelet transformed. In such a manner, the watermark data are efficiently inserted to the entire signals and a signal position to be hardly perceived by another person is selected. |
