Spectral subtraction noise suppression method
AssigneeTelefonaktiebolaget LM Ericsson
InventorPeter Handel
Life of this patent
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Abstract
A spectral subtraction noise suppression method in a frame based digital communication system is described. Each frame includes a predetermined number N of audio samples, thereby giving each frame N degrees of freedom. The method is performed by a spectral subtraction function H(w) which is based on an estimate of the power spectral density of background noise of non-speech frames and an estimate .PHI..sub.x (w) of the power spectral density of speech frames. Each speech frame is approximated by a parametric model that reduces the number of degrees of freedom to less than N. The estimate .PHI..sub.x (w) of the power spectral density of each speech frame is estimated from the approximative parametric model.
Claims10
A spectral subtraction noise suppression method in a frame based digital communication system, each frame including a predetermined number N of audio samples, thereby giving each frame N degrees of freedom, wherein a spectral subtraction function H(.omega.) is based on an estimate .PHI..sub.v (.omega.) of a power spectral density of background noise of non-speech frames and an estimate .PHI..sub.x (.omega.) of a power spectral density of speech frames comprising the steps of:
- approximating each speech frame by a parametric model that reduces the number of degrees of freedom to less than N;
- estimating said estimate .PHI..sub.x (.omega.) of the power spectral density of each speech frame by a parametric power spectrum estimation method based on the approximative parametric model;
- and
- estimating said estimate .PHI..sub.v (.omega.) of the power spectral density of each non-speech frame by a non-parametric power spectrum estimation method.
Dependencies are inferred from the claim text.