Method of denoising an audio signal
First Claim
1. A method of processing an audio signal for denoising a noisy signal that comprises a speech component in combination with a noise component, the noise component itself comprising a transient noise component and a pseudo-steady noise component, the method being characterized in that it is a method of analyzing time coherence of the sampled noisy signal comprising the steps of:
- a) determining a reference signal by applying processing (10, 18) to the noisy signal suitable for attenuating the speech components more strongly than the noise components in said noisy signal, said processing comprising;
a1) applying an adaptive linear prediction algorithm operating on a linear combination of earlier samples of the noisy signal; and
a2) determining said reference signal by taking the difference, with compensation for phase offset, between the noisy signal and the signal delivered by the linear prediction algorithm;
b) determining (24) an a priori probability of speech being present/absent on the basis of the respective energy levels in the spectral domain of the noisy signal and of the reference signal; and
c) using said a priori probability of the absence of speech to estimate a noise spectrum and deriving (26) from the noisy signal a denoised estimate of the speech signal.
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Abstract
This method is a method of analyzing time coherence in the noisy signal and comprises the steps consisting in: a) determining a reference signal from the noisy signal by applying treatment (10, 18) to the noisy signal that is suitable for attenuating speech components more strongly than the noise component, in particular by means of an adaptive recursive predictive algorithm of the LMS type; b) determining (24) a probability of speech being present/absent on the basis of the respective energy levels in the spectral domain of the noisy signal and of the reference signal; and c) deriving (26) a denoised estimate of the speech signal from the noise signal as a function of the probability of the speech being present/absent as determined in this way.
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Citations
8 Claims
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1. A method of processing an audio signal for denoising a noisy signal that comprises a speech component in combination with a noise component, the noise component itself comprising a transient noise component and a pseudo-steady noise component,
the method being characterized in that it is a method of analyzing time coherence of the sampled noisy signal comprising the steps of: -
a) determining a reference signal by applying processing (10, 18) to the noisy signal suitable for attenuating the speech components more strongly than the noise components in said noisy signal, said processing comprising;
a1) applying an adaptive linear prediction algorithm operating on a linear combination of earlier samples of the noisy signal; and
a2) determining said reference signal by taking the difference, with compensation for phase offset, between the noisy signal and the signal delivered by the linear prediction algorithm;
b) determining (24) an a priori probability of speech being present/absent on the basis of the respective energy levels in the spectral domain of the noisy signal and of the reference signal; and
c) using said a priori probability of the absence of speech to estimate a noise spectrum and deriving (26) from the noisy signal a denoised estimate of the speech signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification