Patent ID: 8370140
Filing Date: 2013-02-05
Classification: G10L,H04R

Abstract:
1. A method of de-noising a noisy sound signal picked up by a plurality of microphones of a multi-microphone audio device operating in noisy surroundings, in particular a “hands-free” telephone device for a motor vehicle, the noisy sound signal comprising a useful speech component coming from a directional speech source and an unwanted noise component, the noise component itself including a non-steady lateral noise component that is directional, the method comprising, in the frequency domain for a plurality of frequency bands defined for successive time frames of the signal, the following signal processing steps: a) combining a plurality of signals picked up by the corresponding plurality of microphones to form a noisy combined signal; b) from the noisy combined signal, estimating a pseudo-steady noise component contained in said noisy combined signal; c) from the pseudo-steady noise component estimated in step b) and from the noisy combined signal, calculating a probability of transients being present in the noisy combined signal; d) from the plurality of signals picked up by the corresponding plurality of microphones and from the probability of transients being present as calculated in step c), estimating a main arrival direction of transients; e) from the main arrival direction of transients as estimated in step d), calculating a probability of speech being present on the basis of a three-dimensional spatial criterion suitable for distinguished amongst the transients between useful speech and lateral noise, comprising the following successive substeps: f) from the probability of speech being present as calculated in step e), and from the noisy combined signal, selectively reducing noise by applying variable gain specific to each frequency band and to each time frame.