Performance improvements through combining phone- and syllable-scale information in automatic speech recognition
Su-Lin Wu, Brian E. D. Kingsbury, Nelson H. Morgan, Steven Greenberg · 1998
Combining knowledge derived from both syllable- (100-250 ms) and phone-length (40-100 ms) intervals in the automatic speech recognition process can yield performance superior to that obtained using information derived from a single time scale alone. The results are particularly pronounced for reverberant test conditions that have not been incorporated into the training set. In the present study, phone- and syllable-based systems are combined at three distinct levels of the recognition process --- the frame, the syllable and the entire utterance. Each strategy successfully integrates the complementary strengths of the individual systems, yielding a significant improvement in accuracy on a small-vocabulary, naturally spoken, telephone speech corpus. The syllable-level combination outperformed the other two methods under both relatively pristine and moderately reverberant acoustic conditions, yielding a 20-40% relative improvement over the baseline. 1. SYLLABLES IN ASR Most current auto...