Digital Watermarking Scheme Using Direct-sequence Spread Spectrum with Adaptive Voltage Control for Spread Watermark Signals

摘要

A digital watermarking method using direct sequence spread spectrum is discussed. A new adaptive voltage control method for spread watermark signals is proposed. The strength of the watermark is determined in proportion to the voltage of the music sample. The un-detection probability for the digital watermark is clarified. The detection probability of fake watermark is also examined. The new method makes it possible to maintain a constant music quality for both long and short term SNRs. The detrioration of music quality is evaluated by the subjective opinion test. The result shows that the detrioration can be reduced so as to be hardly perceptible.