| 摘要 |
PROBLEM TO BE SOLVED: To provide a practicable and robust method and a system of digital watermark. SOLUTION: The digital watermark system consists in embedding additional information in digital data. One frame is composed of N samples fetched from the digital data and the following frame is determined, in such a way that it overlaps with the foregoing frame by M(0<M<=N/2) samples. The system has a frequency region converting section, which multiples the frame taken out from the digital data by a windowing function and calculates Fourier transform for determining the frequency component of the digital data, a frequency region burying section which increases or decreases the amplitude of the frequency component of the digital data, determined by the frequency region converting section according to the bit information of the additional information and the frequency band, time area converting section which puts the frequency component whose amplitude is increased or decreased by the frequency region embedding section back into a time area signal by using the inverse Fourier transformation and an additional information burying frame forming section which multiples the time area signal by a windowing function and overlaps the overlapping consecutive frames onto it for forming a frame, in which the additional information are embedded. |
