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Method and system for masking speech

  • US 7,184,952 B2
  • Filed: 07/12/2006
  • Issued: 02/27/2007
  • Est. Priority Date: 07/24/2002
  • Status: Expired due to Fees
First Claim
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1. A method of producing a substantially unintelligible, obfuscated speech signal from intelligible speech, comprising the steps of:

  • obtaining a speech signal representing a speech stream;

    temporally partitioning said speech signal into a plurality of segments, said segments occurring in an initial order within said speech signal;

    selecting a plurality of selected segments from among said segments; and

    assembling said selected segments, in an order different than said initial order, to produce said obfuscated speech signal;

    wherein said segments represent phonemes within said speech stream;

    wherein said temporally partitioning step comprises the steps of;

    squaring said speech signal;

    calculating a short time average of said speech signal over a short time scale;

    calculating a medium time average of said speech signal over a medium time scale;

    calculating a difference between said short time average and said medium time average; and

    detecting zero crossings in said difference;

    wherein said zero crossings delineate said segments.

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