Patent ID: 7272718

Claim:
A signal processing device for superimposing digital watermarking information on an audio signal, said device comprising: psychological auditory sense analysis means for performing psychological auditory sense analysis based on a predetermined compression characteristic of said audio signal, and for outputting the result of the analysis as psychological auditory sense encoded information; and superimposing means for superimposing on said audio signal first digital watermarking information and second digital watermarking information to create a marked audio signal, said first digital watermarking information and said second digital watermarking information being based on said psychological auditory sense encoded information and on at least one range of amplitudes within which a frequency representation of said audio signal is sampled during compression processing such that regions containing first digital watermarking information are sampled during compression processing and regions containing said second digital watermarking information are not sampled during compression processing, and being characterized in that, upon further compression of said marked signal to create a compressed signal, said first digital watermarking information can be completely or substantially recovered from said compressed signal and said second digital watermarking information cannot be completely or substantially recovered from said compressed signal; wherein said psychological auditory sense encoded information is indicative of the respective frequency bands of said audio signal on which said first and second digital watermarking information are to be superimposed, and the respective levels to which the first and second digital watermarking information should be set prior to superimposition.