Patent ID: 8615393
Filing Date: 2013-12-24
Classification: G10L

Abstract:
1. A computer implemented method of generating a noise suppression component with a computer having a processor, the method comprising: accessing, with the processor, a noise suppression rule including a plurality of parameters for altering a speech signal to suppress noise in the speech signal, the plurality of parameters including a voice activity parameter, a noise model builder parameter, and a suppression gain module parameter, the voice activity parameter being utilized to assign probabilities to portions of the speech signal that constitute speech, the noise model builder parameter being utilized to build a probability model of the noise in the speech signal, and the suppression gain module parameter being utilized to determine an amount of gain to apply to the signal; modeling the speech signal and the noise as independent random variables with each of the random variables having an associated variance; applying, with the processor, a maximum mutual information function to the voice activity parameter, the noise model builder parameter, and the suppression gain module parameter to determine a sum of log conditional probabilities based on how accurately a speech recognition output from a speech recognition system represents the speech in the speech signal, the maximum mutual information function including a ratio of the variance of the speech signal to the variance of the noise; adjusting, with the processor, the voice activity parameter, the noise model builder parameter, and the suppression gain module parameter of the noise suppression rule to increase the sum of log conditional probabilities; iteratively repeating the applying and the adjusting to determine a final set of parameters of the noise suppression rule, each iteration utilizing the adjusted parameters obtained from the previous iteration as a starting basis for the current iteration; and providing, with the processor, an adjusted noise suppression rule, as a function of the final set of parameters, to the noise suppression component for use in suppressing noise in a signal subject to speech recognition to thereby increase the recognition accuracy rate of the speech recognition system.