Adaptive noise cancelling for conferencing communication systems
A communication system with a noise cancellation (NC) assembly providing adaptive or dynamic noise cancellation. The NC assembly includes a localizer module determining, during a communication session (active speaking or during idle times), a location of the active talker. The NC assembly includes a beam generator forming a beam in the determined direction of the active talker to enhance the active talker speech. Once the NC assembly has determined the position of the active talker, the NC assembly assigns a microphone of the microphone array or generated beam in that active direction to be the “active signal” source. The NC assembly assigns a second microphone or beam to be the noise source for NC purposes, and this source may be selected to be in acoustic shadow of the first microphone used as the active signal source or may be the farthest away in its position from the active talker's position.
1. An electronic communication system with adaptive noise cancellation, comprising:
an array of microphones at a plurality of positions in a space for receiving a speech signal from one or more audio sources in the space and a noise signal from the space; and
a noise cancellation (NC) assembly comprising a processor executing code or instructions to provide functions of a localizer module and an NC processing module;
wherein the localizer module processes the speech signal from the one or more audio sources to determine a direction of an active talker,
wherein the NC processing module uses a first one of the microphones based on the direction of the active talker as an active talker source and a second one of the microphones, differing from the first one, based on the direction of the active talker as a noise source, and
wherein the NC processing module processes the output of the first and second microphones to generate an audio signal with noise cancellation,
wherein the first one of the microphones is selected to be in a direction matching the direction of the active talker or to be closest in relative position in the array of the microphones to a position of the active talker and wherein the second one of the microphones is selected is selected to be in an acoustical shadow of the first one of the active talker.
2. The electronic communication system of claim 1 , wherein a position of the active talker relative to the array of microphones varies during a communication session.
3. The electronic communication system of claim 2 , wherein, during the communication session, the localizer module second processes the speech signal from the one or more audio sources to determine a second direction for the active talker or a second active talker and wherein, in response, the NC processing module uses a third one of the microphones based on the second direction as the active talker source and a fourth one of the microphones, differing from the third one, based on the second direction.
4. The electronic communication system of claim 1 , wherein the second one of the microphones is selected to be in a direction opposite the direction of the active talker or to be farthest from the first one of the microphones in the array of the microphones.
5. The electronic communication system of claim 1 , wherein the array of microphones includes at least one microphone in a mobile communication device communicatively linked to the NC processing module and wherein a position of the at least one microphone in the mobile communication device is communicated to the NC processing module.
6. The electronic communication system of claim 5 , wherein the NC processing module uses the at least one microphone in the mobile communication device as the noise source when the position of the at least one microphone in the mobile communication device indicates the at least one microphone in the mobile communication device is furthest away from a position of the first one of the microphones being used as the active talker source.
7. The electronic communication system of claim 1 , wherein the NC assembly further comprises a beam generator module operating to build a beam using the direction of the active talker and wherein the NC processing module uses output of the beam generator module along with the output of the noise source to provide the audio signal with noise cancellation.
8. The electronic communication system of claim 7 , wherein the second one of the microphones is selected to have a direction or position in the array that is opposite a direction of the beam.
9. A method of providing adaptive noise cancellation in a communication system, comprising:
operating a plurality of microphones to provide input audio signals;
with a localizer, processing the input audio signals to determine a direction to an active talker relative to the plurality of microphones;
selecting one of the plurality of microphones to be a noise source, wherein the selected one of the plurality of microphones has a direction that is opposite the direction to the active talker or has a position that is furthest among the plurality of microphone away from the active talker;
performing noise cancellation on the input audio signals using output of the noise source; and
selecting one of the plurality of microphones to be an active talker source that matches the direction to the active talker or that has a position that is closest among the plurality of microphone to the active talker, wherein the performing the noise cancellation includes using a signal from the active source along with the output of the noise source.
10. The method of claim 9 , further comprising, with a beamformer, forming a beam by processing the input audio signals from the plurality of microphones, wherein the performing the noise cancellation includes using an output signal from the beamformer along with the output of the noise source.
11. The method of claim 9 , wherein the plurality of microphones includes a microphone of a mobile communication device and wherein the selecting of one of the plurality of microphones to be the noise source includes choosing the microphone of the mobile communication device when it is determined to have a position that is furthest among the plurality of microphone away from the active talker.
12. The method of claim 9 , further comprising repeating the processing, selecting, and performing steps to identify a second direction to the active talker, to select a second one of the plurality of microphones for use as a second noise source based on the second direction to the active talker, and to perform the noise cancellation using an output of the second noise source.
13. An electronic communication system with adaptive noise cancellation, comprising:
an array of microphones;
a localizer module configured to: (a) first, process output signals from the microphones to determine a first direction of an audio source, and fb second, process output signals from the microphones to determine a second direction of the audio source, and
an noise cancellation (NC) processing module configured to: (a) first, select (i) a first one of the microphones based on the first direction of the audio source as a first active source, and (ii) a second one of the microphones as a first noise source that picks up a least amount of energy from the first active source, and (b) second, select (i) a third one of the microphones based on the second direction of the audio source as a second active source, and (ii) a fourth one of the microphones as a second noise source that picks up a least amount of energy from the second active source,
wherein the NC processing module first processes signals of the first active source and the first noise source to generate a first audio signal with noise cancellation and second processes signals of the second active source and the second noise source to generate a second audio signal with noise cancellation, and
wherein the second one of the microphones is selected to be in an acoustical shadow of the first one of the microphones and the fourth one of the microphones is selected to be in an acoustical shadow of the third one of the microphones.
14. The electronic communication system of claim 13 , wherein the array of microphones includes at least one microphone in a mobile communication device communicatively linked to the NC processing module and wherein a position of the at least one microphone in the mobile communication device is communicated to the NC processing module.
15. The electronic communication system of claim 14 , wherein the NC processing module uses the at least one microphone in the mobile communication device as the first or second noise source when the position of the at least one microphone in the mobile communication device indicates the at least one microphone in the mobile communication device is furthest away from a position of the first or third one of the microphones being used as the first or second active source, respectively.
16. The electronic communication system of claim 13 , further comprising a beamformer building a beam using outputs of the microphones and wherein the NC processing module uses first and second output signals of the beam generator module along with the signals of the first and second noise source, respectively, to provide the first and second audio signals with noise cancellation.
17. The electronic communication system of claim 16 , wherein the second one of the microphones is selected to have a direction or position in the array that is opposite a direction of the beam.