Histogram based pre-pruning scheme for active HMMS

摘要

Embodiments of the present invention include an acoustic processing device, a method for acoustic signal processing, and a speech recognition system. The speech processing device can include a processing unit, a histogram pruning unit, and a pre-pruning unit. The processing unit is configured to calculate one or more Hidden Markov Model (HMM) pruning thresholds. The histogram pruning unit is configured to prune one or more HMM states to generate one or more active HMM states. The pruning is based on the one or more pruning thresholds. The pre-pruning unit is configured to prune the one or more active HMM states based on an adjustable pre-pruning threshold. Further, the adjustable pre-pruning threshold is based on the one or more pruning thresholds.

主权项

1. An acoustic processing, device comprising:
an interface for receiving acoustic features obtained from an input analog signal representing an incoming voice signal; a processing unit configured to calculate one or more current Hidden Markov Model (HMM) pruning thresholds; a histogram pruning unit configured to prune one or more current HMM states based on the one or more pruning thresholds to generate one or more active HMM states; a pre-pruning unit configured to prune the one or more active HMM states based on an adjustable pre-pruning threshold to generate active HMM states output of the pre-pruning unit, wherein the adjustable pre-pruning threshold is based on one or more prior pruning thresholds, and wherein the active HMM states output of the pre-pruning unit each indicate a phoneme of the incoming voice signal and are each associated with a HMM state score; and a senone scoring unit configured to provide a senone score to the pre-pruning unit, wherein the pre-pruning unit modifies the adjustable pre-pruning threshold based on the senone score wherein the pre-pruning follows the histogram pruning for a current frame the incoming voice signal and precedes the histogram pruning for a next frame, and wherein the interface transfers the phonemes and their associated HMM state scores to a further speech recognition stage and the further speech recognition stage generates recognized speech corresponding to the incoming voice signal.