A two pass classifier for utterance rejection in keyword spotting

  • Authors:
  • Rafid A. Sukkar;Jay G. Wilpon

  • Affiliations:
  • AT&T Bell Laboratories, Naperville, IL;AT&T Bell Laboratories, Naperville, IL

  • Venue:
  • ICASSP'93 Proceedings of the 1993 IEEE international conference on Acoustics, speech, and signal processing: speech processing - Volume II
  • Year:
  • 1993

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Abstract

A classifier for utterance rejection in a Hidden Markov Model (HMM) based speech recognizer is presented. This classifier, termed the two pass classifier, is a post processor to the HMM recognizer, and consists of a two stage discriminant analysis. The first stage employs the Generalized Probabilistic Descent (GPD) discriminative training framework, while the second stage performs linear discrimination combining the output of the first stage with the HMM likelihood scores. In this fashion the classification power of the HMM is combined with that of the GPD stage which is specifically designed for keyword/non-keyword classification. Experimental results show that, on two separate databases, the two pass classifier significantly outperforms a single pass classifier based solely on the HMM likelihood scores.