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Digital signal watermaker

  • US 7,657,752 B2
  • Filed: 11/04/2004
  • Issued: 02/02/2010
  • Est. Priority Date: 04/24/2001
  • Status: Expired due to Fees
First Claim
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1. A computer-implemented watermarking method, comprising:

  • computing a hash value representative of a digital signal, wherein the computing comprises;

    transforming the digital signal into a digital signal transform;

    randomly dividing the digital signal transform into multiple chunks, each chunk containing signal data, wherein the dividing is carried out recursively to form hierarchical levels of overlapping chunks; and

    averaging, for each of the chunks, the signal data to produce corresponding chunk averages;

    generating, based in part on the chunk averages, an exponential distribution having multiple distinct quantization levels;

    randomly rounding each of the chunk averages to one of the quantization levels to produce rounded values; and

    hashing a composite of the rounded values; and

    watermarking the digital signal with a watermark derived, at least in part, from the hash value.

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