Patent ID: 8010355
Filing Date: 2011-08-30
Classification: G10L

Abstract:
1. A method of reducing noise in a speech signal comprising: converting the speech signal to the frequency domain using a fast fourier transform (FFT); creating a subset of selected spectral subbands; computing, in each subband, the estimated clean speech signal power using a first order autoregressive estimator, the estimated noise power, and the estimated noise speech power; computing a first ratio between the estimated clean speech signal power and the sum of the noise speech power and the clean speech signal power; computing a second ratio between the noise speech power and the estimated noise power; computing the product of the first and second ratios; applying said product as an input to a lookup table to determine the appropriate gain for each subband; interpolating the gains to match the number of FFT points; applying the interpolated gains as filter coefficients to the converted speech signal; and performing an inverse FFT to recover a time domain output signal.