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Content-recognition facilitator

  • US 7,152,163 B2
  • Filed: 11/04/2004
  • Issued: 12/19/2006
  • Est. Priority Date: 04/24/2001
  • Status: Expired due to Fees
First Claim
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1. A computer-implemented hashing method, comprising:

  • transforming an original digital signal into a digital signal transform;

    first computing a hash value representative of the original digital signal such that perceptually distinct digital signals result in hash values that are approximately independent of one another and perceptually similar digital signals result in proximal first hash values, wherein the computing of the first hash value comprises;

    obtaining the digital signal transform of the original digital signal;

    quantizing the digital signal transform;

    geometric-region-growing the digital signal transform;

    based upon the geometrical-region-grown digital signal transform, generating the first hash value of the original digital signal;

    second computing a second hash value in representative of the original digital signal such that perceptually distinct digital signals result in second hash values that are approximately independent of one another and perceptually same digital signals result in identical second hash values, wherein the computing of the second hash value comprises;

    obtaining the digital signal transform of the original digital signal;

    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;

    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;

    hashing a composite of the rounded values;

    storing the first and second hash values in relationship with the original digital signal;

    watermarking the original digital signal using, in part, the hash value to produce a watermarked original digital signal;

    subsequently distributing the watermarked original digital signal over a network;

    collecting a subject digital signal from a remote site on the network;

    in accordance with the first computing act, computing a hash value of the subject digital signal collected from the remote site;

    comparing the hash value of the collected subject digital signal with the stored hash value of the original digital signal;

    in accordance with the second computing act, computing a second hash value of the subject digital signal collected from the remote site;

    comparing the second hash value of the collected subject digital signal with the stored second hash value of the original digital signal; and

    identifying the collected subject digital signal as a pirated version of the original digital signal if the second hash values match.

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