Environmental noise suppression method
A voice pick-up arrangement ( 500 ) provides improved voice performance in a wireless headset ( 12 ) exposed to loud environmental noise. A air microphone ( 220 ) and a vibration sensor ( 230 ) are used for sound pickup. An adaptive filter ( 450 ) may be used to subtract the noise from the vibration sensor output in a subtractor ( 460 ), thus producing a clear voice signal. A noise level may be monitored and be used for determining whether the adaptive filter is used or for determining the coefficients of the adaptive filter ( 450 ). A beam-forming array may be used to suppress a voice component of the picked-up air microphone audio signal.
1 . A method for reducing noise in voice pickup in headsets, wherein the method comprises steps of:
generating a first audio signal by picking up sounds using one or more vibration sensors;
generating a second audio signal by picking up sounds using one or more air microphones;
adaptive filtering the second audio signal using an adaptive filter;
monitoring a noise level in the first audio signal and/or the second audio signal;
configuring the adaptive filter based on the monitored noise level;
generating a third audio signal by combining the first audio signal and the second audio signal; and
generating an output audio signal by combining the first, second, and third audio signals as a weighted sum, wherein weight factors are applied to the first, second, and third audio signals before summing.
2 . The method of claim 1 , wherein the step of generating the third audio signal comprises subtracting the second audio signal from the first audio signal to obtain a subtracted output audio signal, the subtracted output audio signal being the third audio signal.
3 . The method of claim 2 , wherein subtracting the second audio signal from the first audio signal comprises adaptively filtering the second audio signal before subtracting.
4 . The method of claim 3 , wherein configuring the adaptive filter further comprises configuring the adaptive filter based on the subtracted output audio signal.
5 . The method according to claim 1 , wherein the monitoring step uses spectral analysis for determining the measured noise level.
6 . The method according to claim 1 , wherein the step of generating the output audio signal includes using voice detection.
7 . The method according to claim 1 , wherein the method further comprises a step of:
applying a beam-forming array comprising at least two air microphones configured to suppress a voice component in the second audio signal.
8 . The method according to claim 1 , wherein the method further comprises a step of wirelessly sending the first audio signal to a wireless headset.
9 . The method of claim 1 , wherein the method further comprises:
determining the weight factors depending on the monitored noise level.
10 . A headset comprising:
one or more vibration sensors arranged to pick up sounds to generate a first audio signal;
one or more air microphones arranged to pick up sounds to generate a second audio signal;
an adaptive filter arranged to adaptively filter the second audio signal;
a noise level sensor arranged to obtain a noise level signal;
a microprocessor configured to generate a third audio signal by combing the first and second audio signals and to generate an output audio signal by combining the first, second, and third audio signals as a weighted sum, wherein weight factors are applied to the first, second, and third audio signals before summing,
wherein the microprocessor is further configured to configure the adaptive filter based on the noise level signal.
11 . The headset of claim 10 , wherein the headset is a wireless headset.
12 . The headset of claim 10 , wherein the microprocessor is arranged as a subtractor for subtracting the second audio signal from the first audio signal to obtain a subtracted output audio signal, the subtracted output audio signal being the third audio signal.
13 . The headset of claim 12 , wherein the adaptive filter is further arranged to adaptively filter the second audio signal fed to the subtractor, and wherein the adaptive filter is based on the subtracted output audio signal.
14 . The headset of claim 12 , wherein the microprocessor is arranged to combine the subtracted output audio signal with the first audio signal and/or second audio signal dependent on the noise level signal.
15 . The headset of claim 10 , wherein the headset further comprises a beam-forming array comprising at least two air microphones configured to suppress a voice component in the second audio signal.
16 . The headset of claim 13 , wherein the headset further comprises a noise level sensor arranged to obtain a noise level signal, and-wherein the adaptive filter adapts its coefficients dependent on the noise level signal.
17 . The headset of claim 12 , wherein the headset comprises a radio transceiver for wireless communication of the subtracted output audio signal to an external device.
18 . The headset of claim 17 , wherein the radio transceiver is based on Bluetooth®.