Patent ID: 6370505
Filing Date: 2002-04-09
Classification: G10L

Abstract:
A method of processing speech, the method comprising:receiving the speech and determining therefrom an input speech vector (or) representing a sample of the speech to be processed; and, determining the likelihoods of a number of possible output states (j) corresponding to the input speech vector (or), wherein each output state (j) is represented by a number of state mixture components (m), each state mixture component being a probability distribution function approximated by a weighted sum of a number of predetermined generic components (x), the approximation including the step of determining a weighting parameter (wjmx) for each generic component (x) for each state mixture component (m), the method of determining the output state (j) likelihoods comprising the steps of: 1) generating a correspondence probability signal representing a correspondence probability (Prx), wherein the correspondence probability (Prx) is the probability of each respective generic component (x) corresponding to the input speech vector (or); 2) generating a threshold signal, representing a threshold value Tmix; 3) selecting a number of output states (Nj); 4) determining, for each state mixture component (m) of each selected output state (j), whether a weighted probability (gjmr) given by the scalar product of the weighting parameters (wjmx) and the respective correspondence probabilities (Prx), exceeds the threshold value Tmix; and, 5) generating a set of output signals representing state likelihoods (bj) for each selected output state (j) by evaluating the likelihoods of all the state mixture components (m) of the respective selected output state (j) which have a weighted probability (gjmr) exceeding the threshold Tmix.