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Acoustic signal classification system

  • US 7,957,967 B2
  • Filed: 09/29/2006
  • Issued: 06/07/2011
  • Est. Priority Date: 08/30/1999
  • Status: Expired due to Fees
First Claim
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1. A method for classifying an input signal, comprising:

  • establishing a first signal model;

    obtaining an input signal;

    determining a time-frequency representation of the input signal;

    determining, by a processor, whether a harmonic is present in the time-frequency representation;

    initiating spectrogram template matching, using the first signal model, in response to determining that the harmonic is present; and

    forgoing spectrogram template matching when the harmonic is not present;

    where determining whether the harmonic is present comprises;

    determining a frequency range to scan;

    scanning the time-frequency representation over the frequency range;

    identifying local peaks in the frequency range that exceed neighboring spectrum values by more than a peak threshold;

    counting votes for the local peaks;

    determining a normalized vote ratio using an expected number of harmonics in the frequency range; and

    comparing the normalized vote ratio to a harmonic threshold.

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