AUDIO EQUIPMENT INCLUDING MEANS FOR DE-NOISING A SPEECH SIGNAL BY FRACTIONAL DELAY FILTERING, IN PARTICULAR FOR A "HANDS-FREE" TELEPHONY SYSTEM
First Claim
1. Audio equipment, comprising:
- a set of two microphone sensors suitable for picking up the speech of the user of the equipment and for delivering respective noisy speech signals;
sampling means for sampling the speech signals delivered by the microphone sensors; and
de-noising means for de-noising a speech signal, the de-noising means receiving as input the samples of the speech signals delivered by the two microphone sensors and delivering as output a de-noised speech signal representative of the speech uttered by the user of the equipment;
wherein;
the de-noising means are non-frequency noise reduction means comprising an adaptive filter combiner for combining the signals delivered by the two microphone sensors, operating by iterative searching seeking to cancel the noise picked up by one of the microphone sensors on the basis of a noise reference given by the signal delivered by the other microphone sensor;
the adaptive filter is a fractional delay filter suitable for modeling a delay shorter than the sampling period of the sampling means;
the equipment further includes voice activity detector means suitable for delivering a signal representative of the presence or the absence of speech from the user of the equipment; and
the adaptive filter also receives as input the speech present or absent signal so as to act selectively;
i) either to perform an adaptive search for filter parameters in the absence of speech;
ii) or else to “
freeze”
those parameters of the filter in the presence of speech.
2 Assignments
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Accused Products
Abstract
The equipment comprises two microphones, sampling means, and de-noising means. The de-noising means are non-frequency noise reduction means comprising a combiner having an adaptive filter performing an iterative search seeking to cancel the noise picked up by one of the microphones on the basis of a noise reference given by the other microphone sensor. The adaptive filter is a fractional delay filter modeling a delay that is shorter than the sampling period. The equipment also has voice activity detector means delivering a signal representative of the presence or the absence of speech from the user of the equipment. The adaptive filter receives this signal as input so as to enable it to act selectively: i) either to perform an adaptive search for the parameters of the filter in the absence of speech; ii) or else to “freeze” those parameters of the filter in the presence of speech.
54 Citations
8 Claims
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1. Audio equipment, comprising:
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a set of two microphone sensors suitable for picking up the speech of the user of the equipment and for delivering respective noisy speech signals; sampling means for sampling the speech signals delivered by the microphone sensors; and de-noising means for de-noising a speech signal, the de-noising means receiving as input the samples of the speech signals delivered by the two microphone sensors and delivering as output a de-noised speech signal representative of the speech uttered by the user of the equipment; wherein; the de-noising means are non-frequency noise reduction means comprising an adaptive filter combiner for combining the signals delivered by the two microphone sensors, operating by iterative searching seeking to cancel the noise picked up by one of the microphone sensors on the basis of a noise reference given by the signal delivered by the other microphone sensor; the adaptive filter is a fractional delay filter suitable for modeling a delay shorter than the sampling period of the sampling means; the equipment further includes voice activity detector means suitable for delivering a signal representative of the presence or the absence of speech from the user of the equipment; and the adaptive filter also receives as input the speech present or absent signal so as to act selectively;
i) either to perform an adaptive search for filter parameters in the absence of speech;
ii) or else to “
freeze”
those parameters of the filter in the presence of speech. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification