Patent ID: 8280731

Claim:
A method for enhancing speech components of an audio signal composed of speech and noise components, comprising transforming the audio signal from the time domain to a plurality of subbands in the frequency domain, wherein each of said plurality of subbands is presumed to have a speech component and a noise component, said noise component having an amplitude and a variance at time index m, wherein said amplitude of the noise component is estimated by exploiting statistical differences that distinguish between the speech component and the noise component, processing each of said plurality of subbands, said processing including applying a gain factor, wherein said gain factor is derived at least in part from an estimation of said variance in noise components, wherein the estimation comprises at each time index m, updating said estimation of variance in noise components of the subband signal from an average of past estimates of the amplitude of noise components in the subband signal, and wherein said past estimates of the amplitude of noise components in the subband signal having values greater than a threshold are excluded from or underweighted in said weighted average, and transforming the processed subband signal from the frequency domain to the time domain to provide an audio signal in which speech components are enhanced.