Frame-dependent multi-stream reliability indicators for audio-visual speech recognition

Ashutosh Garg, Gerasimos Potamianos, Chalapathy Neti, Thomas S. Huang

Research output: Contribution to journalConference articlepeer-review


We investigate the use of local, frame-dependent reliability indicators of the audio and visual modalities, as a means of estimating stream exponents of multi-stream hidden Markov models for audio-visual automatic speech recognition. We consider two such indicators at each modality, defined as functions of the speech-class conditional observation probabilities of appropriate audio-or visual-only classifiers. We subsequently map the four reliability indicators into the stream exponents of a state-synchronous, two-stream hidden Markov model, as a sigmoid function of their linear combination. We propose two algorithms to estimate the sigmoid weights, based on the maximum conditional likelihood and minimum classification error criteria. We demonstrate the superiority of the proposed approach on a connected-digit audio-visual speech recognition task, under varying audio channel noise conditions, Indeed, the use of the estimated, frame-dependent stream exponents results in a significantly smaller word error rate than using global stream exponents. In addition, it outperforms utterance-level exponents, even though the latter utilize a-priori knowledge of the utterance noise level.

Original languageEnglish (US)
Pages (from-to)24-27
Number of pages4
JournalICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings
StatePublished - 2003
Externally publishedYes
Event2003 IEEE International Conference on Accoustics, Speech, and Signal Processing - Hong Kong, Hong Kong
Duration: Apr 6 2003Apr 10 2003

ASJC Scopus subject areas

  • Software
  • Signal Processing
  • Electrical and Electronic Engineering


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