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Recognition confidence measuring by lexical distance between candidates

  • US 8,990,086 B2
  • Filed: 07/31/2006
  • Issued: 03/24/2015
  • Est. Priority Date: 02/09/2006
  • Status: Expired due to Fees
First Claim
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1. A recognition confidence measurement method comprising:

  • detecting a feature vector of an input speech signal through normalization of a histogram and extracting a phoneme string from the detected feature vector of the input speech signal;

    obtaining information about a distance between a phoneme string of the input speech signal and a phoneme string of a predetermined vocabulary, by a predetermined phoneme confusion matrix, wherein the phoneme confusion matrix sets the distance to be decreased in proportion to the increase of the matching degree between phonemes;

    extracting as candidates, the phoneme string of the vocabulary that has a higher similarity which denotes a comparatively shorter distance from the speech signal, from a predetermined dictionary;

    estimating a lexical distance between the extracted candidates, the estimating of the lexical distance comprising selecting a pair of candidates from the extracted candidates and performing a dynamic matching of the selected pair of candidates; and

    determining whether the input speech signal is an in-vocabulary, based on the lexical distance, wherein the dynamic matching comprises;

    for each phoneme in a first candidate of the selected pair of candidates, determining as a first matching pair the phoneme in the first candidate and the corresponding phoneme in a second candidate of the selected pair of candidates and determining as a second matching pair the phoneme in the first candidate and a phoneme having an identical shape to the phoneme in the first candidate;

    wherein the estimating of the lexical distance further comprises;

    calculating a score for the pair of candidates; and

    estimating the lexical distance using the calculated score;

    wherein the calculating of the score calculates the score using the phoneme confusion matrix.

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