Patent ID: 8145488
Filing Date: 2012-03-27
Classification: G10L

Abstract:
1. A speech recognition system, comprising: a speech recognition module for using variable-parameter hidden Markov models (VPHMMs) to recognize speech based on extracted speech features and at least one environmental conditioning parameter; and a store in computer memory for storing at least one shared set of parameters that represents a class of piecewise functions for use by the VPHMMs, each of the VPHMMs using a plurality of mixture components L in modeling state observations, and a particular mixture component l of the plurality of mixture components L having at least one mixture component parameter that varies as a function of said at least one environmental conditioning parameter, as approximated by using a piecewise function that includes a plurality of connected segments, the particular mixture component l having a mean parameter μ and a variance parameter Σ that are functions of said at least one environmental conditioning parameter ζ, as represented by: where i identifies a state, d identifies a dimension, ζ refers to said at least one environmental conditioning parameter, r refers to utterance, t refers to frame, ξ refers to a spline function which serves as the piecewise function, μ the particular mixture component l making reference to said at least one shared set of parameters in the store to constitute the piecewise function.