Abstract: A system for, and method of, developing high accuracy acoustic models and a digital signal processor incorporating the same. In one embodiment, the system includes: (1) an acoustic model initializer configured to generate initial acoustic models by seeding with seed monophones, (2) a monophone retrainer associated with the acoustic model initializer and configured to retrain the monophones using a target database, (3) a triphone generator associated with the monophone retrainer and configured to generate seed triphones from the monophones using aligned training data, (4) a triphone retrainer associated with the triphone generator and configured to retrain the triphones using the target database and (5) a triphone clusterer associated with the triphone retrainer and configured to cluster the triphones using a state-tying technique, the triphone retrainer configured to retrain the triphones again using the target database.

Abstract: A system for, and method of, combined state- and phone-level pronunciation adaptation. One embodiment of the system includes: (1) a state-level pronunciation variation analyzer configured to use an alignment process to compare base forms of words with alternate pronunciations and generate a confusion matrix, (2) a state-level pronunciation adapter associated with the state-level pronunciation variation analyzer and configured to employ the confusion matrix to generate, in plural states, sets of Gaussian mixture components corresponding to alternative pronunciation realizations and enlarge the sets by tying the Gaussian mixture components across the states based on distances among the Gaussian mixture components and (3) a phone-level pronunciation adapter associated with the state-level pronunciation adapter and configured to employ phone-level re-write rules to generate multiple pronunciation entries. The phone-level pronunciation adapter may be embodied in multiple stages.

Abstract: A system for, and method of, noisy automatic speech recognition employing joint compensation of additive and convolutive distortions and a digital signal processor incorporating the system or the method. In one embodiment, the system includes: (1) an additive distortion factor estimator configured to estimate an additive distortion factor, (2) an acoustic model compensator coupled to the additive distortion factor estimator and configured to use estimates of a convolutive distortion factor and the additive distortion factor to compensate acoustic models and recognize a current utterance, (3) an utterance aligner coupled to the acoustic model compensator and configured to align the current utterance using recognition output and (4) a convolutive distortion factor estimator coupled to the utterance aligner and configured to estimate an updated convolutive distortion factor based on the current utterance using differential terms but disregarding log-spectral domain variance terms.

Abstract: A system for, and method of, creating generalized tied-mixture hidden Markov models (HMMs) for noisy automatic speech recognition. In one embodiment, the system includes: (1) an HMM estimator and state tyer configured to perform HMM parameter estimation and state-tying with respect to word transcriptions and a pronunciation dictionary to yield continuous-density HMMs and (2) a mixture tyer associated with the HMM estimator and state tyer and configured to tie Gaussian mixture components across states of the continuous-density HMMs and a phone confusion matrix thereby to yield the generalized tied-mixture HMMs.

Abstract: A system for, and method of, noisy automatic speech recognition (ASR) and a digital signal processor (DSP) incorporating the system or the method.

Abstract: A system for, and method of, noisy automatic speech recognition employing joint compensation of additive and convolutive distortions and a digital signal processor incorporating the system or the method. In one embodiment, the system includes: (1) an additive distortion factor estimator configured to estimate an additive distortion factor, (2) an acoustic model compensator coupled to the additive distortion factor estimator and configured to use estimates of a convolutive distortion factor and the additive distortion factor to compensate acoustic models and recognize a current utterance, (3) an utterance aligner coupled to the acoustic model compensator and configured to align the current utterance using recognition output and (4) a convolutive distortion factor estimator coupled to the utterance aligner and configured to estimate an updated convolutive distortion factor based on the current utterance using first-order differential terms but disregarding log-spectral domain variance terms.