Muting a sound source with an array of microphones

Patent metadata

Field	Value
Publication number	US-9451360-B2
Application number	US-201414154975-A
Country	US
Kind code	B2
Filing date	Jan 14, 2014
Priority date	Jan 14, 2014
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A processing system can include tracking microphone array(s), audio-tracking circuitry configured to detect a location of audio sources from audio signals from the array(s), and processing circuitry. The processing circuitry can be configured to: identify a first microphone that has a strongest signal strength; estimate a location of an active speaker based on at least an output of the audio-tracking circuitry; determine whether a second microphone for the active speaker is affected by an acoustic obstacle based on the location of the active speaker and a location of the first microphone that has the strongest signal strength; estimate attenuation for microphones based on a comparison of actual signal strengths of the microphones with estimated signal strengths of the microphones that are estimated based on microphone signals of the second microphone for the active speaker; and modify the attenuation based on an estimated location of the acoustic obstacle.

First claim

The invention claimed is:

1. A processor, comprising circuitry configured to:
identify a first microphone, from a plurality of microphones, that has a strongest signal strength;
estimate a location of an active speaker;
determine whether a second microphone, of the plurality of microphones, for the active speaker is affected by an acoustic obstacle based on the location of the active speaker and a location of the first microphone that has the strongest signal strength;
estimate attenuation for the first microphone based on a comparison of actual signal strength of the second microphone with estimated signal strength of the second microphone, wherein the estimated signal strength is estimated based on microphone signals of the second microphone for the active speaker; and
modify the attenuation based on an estimated location of the acoustic obstacle.

2. The processor according to claim 1 , wherein the circuitry is further configured to:
identify a microphone, from the microphones, that has a strongest signal strength at a high frequency; and
estimate the location of the acoustic obstacle based on a comparison of signal strengths of the microphones at the high frequency with a high-frequency reference calibration of the microphones with an active speaker at the high frequency.

3. The processor according to claim 2 , wherein the circuitry is configured to estimate the estimated signal strengths based on the microphone signals at a full-range of frequencies of the second microphone for the active speaker and a full-range reference calibration of the microphones with an active speaker at the full-range of frequencies.

4. The processor according to claim 3 , wherein the full-range reference calibration is a relative signal level matrix (RSLM) that stores relative signal levels of the microphones with an active speaker at the full-range of frequencies.

5. The processor according to claim 4 , wherein the circuitry is configured to generate the RSLM by measuring relative signal strengths of the microphones at the full-range of frequencies with one or more known active speakers without obstacles and store the RSLM in a memory.

6. The processor according to claim 5 , wherein the relative signal levels of the microphones of the RSLM are based on microphone distances and are estimated by the circuitry statistically according to acoustic characteristics of an environment that includes the microphones and only one active speaker.

7. The processor according to claim 2 , wherein the high-frequency reference calibration of the microphones with an active speaker is a relative signal level matrix—high frequency (RSLM-H) that stores relative signal levels of the microphones with an active speaker at the high frequency.

8. The processor according to claim 7 , wherein the relative signal levels of the microphones of the RSLM-H are estimated by the circuitry statistically according to acoustic characteristics of an environment that includes the microphones and only one active speaker.

9. The processor according to claim 7 , wherein the circuitry is configured to generate the RSLM-H by measuring relative signal strengths of the microphones at the high frequency with one or more known active speakers without obstacles and store the RSLM-H in a memory.

10. The processor according to claim 2 , wherein the high frequency is about 2 kHz or higher.

11. The processor according to claim 1 , wherein the circuitry is further configured to determine whether the active speaker is in a muted zone, and estimate the attenuation based on whether the active speaker is in the muted zone.

12. The processor according to claim 1 , wherein the circuitry is further configured to apply the modified attenuation to microphone signals of one or more of the microphones in one or more unmuted zones.

13. The processor according to claim 12 , wherein the circuitry is further configured to package audio signals based on the microphone signals after the modified attenuation has been applied and transmit the packaged audio signals to a remote device.

14. The processor according to claim 1 , wherein the circuitry is further configured to:
package audio signals based on microphone signals of one or more of the microphones in one or more unmuted zones,
separately package attenuation data with data corresponding to the modified attenuation, and
transmit the packaged audio signals and the separately packaged attenuation data to a remote device.

15. The processor according to claim 1 , wherein the circuitry is further configured to:
receive images from one or more cameras;
identify the acoustic obstacle in the images; and
generate the estimated location of the acoustic obstacle from the images.

16. A telepresence processing system, comprising:
one or more tracking microphone arrays,
audio-tracking circuitry configured to detect a location of audio sources from audio signals from the one or more tracking microphone arrays, and
processing circuitry configured to:
identify a first microphone, from a plurality of microphones, that has a strongest signal strength;
estimate a location of an active speaker based on at least an output of the audio-tracking circuitry;
determine whether a second microphone, of the plurality of microphones, for the active speaker is affected by an acoustic obstacle based on the location of the active speaker and a location of the first microphone that has the strongest signal strength;
estimate attenuation for the first microphone based on a comparison of actual signal strength of the second microphone with estimated signal strength of the second microphone, wherein the estimated signal strength is estimated based on microphone signals of the second microphone for the active speaker; and
modify the attenuation based on an estimated location of the acoustic obstacle.

17. The processing system according to claim 16 , further comprising:
a network transmitter, wherein
the processing circuitry is configured to apply the modified attenuation to microphone signals of one or more of the microphones in one or more unmuted zones, and package audio signals based on the microphone signals after the modified attenuation has been applied, and
the network transmitter is configured to transmit the packaged audio signals to a remote device.

18. The processing system according to claim 16 , further comprising:
one or more cameras to capture video of at least the active speaker, wherein
the processing circuitry is configured to package video signals based on an output of the one or more cameras, and
the network transmitter is configured to transmit the packaged video signals with the packaged audio signals to a remote device.

19. A method, comprising:
identifying, by circuitry, a first microphone, from a plurality of microphones, that has a strongest signal strength;
estimating, by circuitry, a location of an active speaker;
determining, by circuitry, whether a second microphone, of the plurality of microphones, for the active speaker is affected by an acoustic obstacle based on the location of the active speaker and a location of the first microphone that has the strongest signal strength;
estimating, by circuitry, attenuation for the first microphone based on a comparison of actual signal strength of the second microphone with estimated signal strength of the second microphone, wherein the estimated signal strength is estimated based on microphone signals of the second microphone for the active speaker; and
modifying, by circuitry, the attenuation based

Assignees

• Cisco Tech Inc

Inventors

• Bao Feng
• Kunapuli Subrahmanyam
• Yang Fei
• Sundsbarm Tor

Classifications

• H04R3/005 Primary

  for combining the signals of two or more microphones (specially adapted for hearing aids H04R25/407) · CPC title

• H04M3/568

  audio processing specific to telephonic conferencing, e.g. spatial distribution, mixing of participants (echo suppression in two-way loud-speaking telephone systems H04M9/02; sound field processing per se H04S7/30) · CPC title

• H04N7/15

  Conference systems · CPC title

• H04M2203/509

  Microphone arrays · CPC title