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Speech recognition system

  • US 4,624,011 A
  • Filed: 01/28/1983
  • Issued: 11/18/1986
  • Est. Priority Date: 01/29/1982
  • Status: Expired due to Fees
First Claim
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1. A speech recognition system comprising:

  • means for converting audible input speech into an input sheech signal;

    acoustic signal processing means for extracting first feature data, second feature data and third feature data from the input speech signal, the first feature data being a time-frequency spectrum pattern data comprising a plurality of frame data arranged on a time axis, and each of the frame data being frequency spectrum data obtained at each of predetermined time points on the time axis, the second feature data being phoneme data obtained in respective frames defining respecitve computation intervals, the frequency range of the input speech signal being divided into a plurality of channels and the frequency spectrum data being obtained at each channel, the phoneme data of each frame being labelled with a prescribed character, and the third feature data being a coded acoustic feature data, the frequency spectrum data of each frame being divided into gross spectrum envelopes;

    a buffer memory means for storing the first to third feature data;

    a reference pattern memory means for storing first, second and third reference data eacha similarity computation circuit for computing similarities between the first to third feature data and the first to third reference data, respectively;

    means for determining a word class pattern having a first reference pattern which gives a largest similarity as being the input speech signal when the largest similarity is larger than a prescribed value and when a difference between the largest sililarity and a second largest similarity is larger than a prescribed value;

    means for extracting m classes of patterns of reference patterns which give the largest to mth largest similarities when the word class pattern is regarded not to correspond to the input speech signal;

    means for computing similarities between the second feature data and the second reference data and between the third feature data and the third reference data for determining whether or not one of said m classes of patterns correspond to the input speech signal.

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