Patent ID: 9224393
Filing Date: 2015-12-29
Classification: G10L,H04M,H04R

Abstract:
1. A method for audio signal processing, the method comprising: in one or more frequency subbands, receiving M communication signals in time frames and comprising a target signal and a noise signal, where M≧2; in each subband, processing the M subband communication signals with a set of beamformer coefficients to obtain a beamformer output signal; in each subband, processing the M subband communication signals in N linearly independent target-cancelling beamformers, where 1≦N<M, to obtain N target-cancelled signals wherein the target signal is suppressed relative to the noise signal; processing the communication signals with a target absence detector to obtain a target absence signal; in each subband, estimating a covariance matrix of order N of the target-cancelled signals as an average, where individual time frames are weighted as a function of the target absence signal; in each subband, estimating an inverse target-cancelled covariance matrix of order N; in each subband, determining a real-valued scaling factor in dependence of the inverse target-cancelled covariance matrix and the N target-cancelled signals; in each subband, determining an initial estimate of the noise power in the beamformer output signal as an average, where individual time frames are weighted using said function of the target absence signal; in each subband, multiplying the initial noise estimate with the scaling factor to obtain a refined estimate of the noise power in the beamformer output signal.