Augmented state space acoustic decoding for modeling local variability in speech

This paper presents a decoding method for automatic speech recognition (ASR) that reduces the impact of local spectral and temporal variabilities on ASR performance. The procedure involves augmenting the standard Viterbi search for an optimum state sequence with a locally constrained search for optimum degrees of spectral warping or temporal warping applied to individual analysis frames. It is argued in the paper that this represents an efficient and effective method for compensating for local variability in speech which may have potential application to a broader array of speech transformations. The techniques are presented in the context of existing methods for frequency warping based speaker normalization and existing methods for computation of dynamic features for ASR. The modified decoding algorithms were evaluated in both clean and noisy task domains usin