METHOD FOR OPTIMIZED FILTRATION OF NON-STATIONARY NOISES CAPTURED BY A MULTI-MICROPHONE AUDIO DEVICE, IN PARTICULAR A 'HANDS-FREE' TELEPHONE DEVICE FOR A MOTOR VEHICLE

摘要

The method comprises in the frequency domain the following steps: a) calculating (18) a first noise reference by spatial coherence analysis of the signals received; b) calculating (20) a second noise reference by analyzing the directions of incidence of the received signals; c) estimating (24) a principal direction of incidence (θ (k, l)) of the captured signals; d) selecting (22) as a referent noise signal (Ref (k, l)) from one or the other of the noise references as a function of the estimated main direction; e) combining (28) the captured signals into a noisy combined signal (X (k, l)); f) calculating (26) an absence of speech probability (q (k, l)) in the noisy combined signal, from respective spectral energy levels of the noisy combined signal (X (k, l)) and the reference noise signal (Ref (k, l)); and g) selectively reducing noise (34) by applying a variable gain specific to each frequency band and each time frame.