Audio processing device, receiver and filtering method for filtering a useful signal and restoring it in the presence of ambient noise
AssigneeKoninklijke Philips Electronics N.V.
InventorGilles Miet
Life of this patent
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Abstract
An audio processing device includes an analyzer and a filter. The analyzer extracts an envelope of a noise signal and derives therefrom noise envelope parameters. The filter has coefficients which vary in response to noise envelope parameters and filters a useful signal to form a filtered signal. The coefficients are varied so that the filter enhances frequency bands of the useful signal that correspond to frequency bands of the noise signal having a higher energy than a predetermined value.
Claims21
An audio processing device for filtering a useful signal, that has a spectral envelope situated in the voice band, and for restoring the useful signal in the presence of ambient noise, comprising means for tapping the ambient noise, spectral envelope extraction means for extracting envelope parameters of the ambient noise and digital filter means controlled by said envelope parameters for modifying the spectral envelope of the useful signal to be restored, said digital filter means comprising a digital filter having coefficients that can be parameterized, and co-operate with said envelope extraction means for parameterizing the digital filter using the envelope parameters.
A filtering method of filtering a useful signal, and restoring the useful signal in the presence of ambient noise, comprising the following steps:
- an acquisition and spectral analysis step of tapping the ambient noise, extracting an estimate of a spectral envelope therefrom and of deriving envelope parameters therefrom,
- a step of calculating a time average between the envelope parameters to obtain average parameters,
- a parameterizing step of parameterizing a digital filter using said average parameters, and
- a filtering step of filtering the useful signal using said digital filter.
An audio processing device comprising:
- an analyzer which extracts an envelope of a noise signal and derives noise envelope parameters;
- and
- a filter having coefficients which vary in response to said noise envelope parameters;
- said filter filtering a useful signal to form a filtered signal.
A method of filtering a useful signal comprising:
- extracting an envelope of a noise signal;
- deriving noise envelope parameters from said envelope;
- varying coefficients of a filter in response to said noise envelope parameters;
- and
- filtering said useful signal to form a filtered signal.
Dependencies are inferred from the claim text.