Systems, methods, apparatus, and computer-readable media for multi-microphone location-selective processing

• US 9,025,782 B2
• Filed: 07/25/2011
• Issued: 05/05/2015
• Est. Priority Date: 07/26/2010
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Visser, Erik, Liu, Ian Ernan
• Primary Examiner(s): Saunders, Jr., Joseph
• Application Number:
  US13/190,162
• Publication Number:
  US 20120020485A1
• Time in Patent Office: 1,380 Days
• Field of Search: 381/23.1
• US Class Current: 381/57
• CPC Class Codes: G10L 2021/02166 Microphone arrays; Beamforming
• CPC Class Codes: H04R 2201/107 Monophonic and stereophonic headphones with microphone for two-way hands free communication
• CPC Class Codes: H04R 2410/05 Noise reduction with a separate noise microphone
• CPC Class Codes: H04R 2430/20 Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic H04R2203/12 takes precedence
• CPC Class Codes: H04R 2430/21 Direction finding using differential microphone array [DMA]
• CPC Class Codes: H04R 25/407 Circuits for combining signals of a plurality of transducers
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10

Abstract

A multi-microphone system performs location-selective processing of an acoustic signal, wherein source location is indicated by directions of arrival relative to microphone pairs at opposite sides of a midsagittal plane of a user'"'"'s head.

Claims

1. A method of audio signal processing, said method comprising:

calculating a first direction indication of a direction of arrival, relative to a first pair of microphones, of a first sound component received by the first pair of microphones;

calculating a second direction indication of a direction of arrival, relative to a second pair of microphones that is separate from the first pair, of a second sound component received by the second pair of microphones, wherein the first and second pair of microphones are worn by a user; and

using the first and second direction indications to control a gain of an audio signal to produce an output signal,

wherein the microphones of the first pair are located at a first side of the midsagittal plane of a head of the user,

wherein the microphones of the second pair are located at a second side of the midsagittal plane that is opposite to the first side, and

wherein controlling the gain comprises determining whether both of the first direction indication and the second direction indication indicate directions of arrival that intersect the midsagittal plane.

2. The method of claim 1, wherein the audio signal includes audio-frequency energy from a signal produced by at least one microphone among the first and second pairs.

3. The method of claim 1, wherein the audio signal includes audio-frequency energy from a signal produced by a voice microphone, and

wherein the voice microphone is located in a coronal plane of the head of the user that is closer to a central exit point of a voice of the user than at least one microphone of each of the first and second microphone pairs.

4. The method of claim 1, wherein said method comprises, based on audio-frequency energy of the output signal, calculating a plurality of linear prediction coding filter coefficients.

5. The method of claim 1, wherein said calculating the first direction indication includes calculating, for each among a plurality of different frequency components of a multichannel signal that is based on signals produced by the first pair of microphones, a difference between a phase of the frequency component in a first channel of the multichannel signal and a phase of the frequency component in a second channel of the multichannel signal.

6. The method of claim 1, wherein the locations of the microphones of the first pair are along a first axis, and

wherein the locations of the microphones of the second pair are along a second axis, and

wherein each among the first and second axes is not more than forty-five degrees from parallel to a line that is orthogonal to the midsagittal plane.

7. The method of claim 6, wherein each among the first and second axes is not more than thirty degrees from parallel to a line that is orthogonal to the midsagittal plane.

8. The method of claim 6, wherein each among the first and second axes is not more than twenty degrees from parallel to a line that is orthogonal to the midsagittal plane.

9. The method of claim 1, wherein said controlling the gain comprises attenuating the audio signal unless both of the first direction indication and the second direction indication indicate directions of arrival that intersect the midsagittal plane.

10. The method of claim 1, wherein said controlling the gain comprises attenuating the audio signal in response to at least one among the first and second direction indications indicating a corresponding direction of arrival that is away from the midsagittal plane.

11. The method of claim 10, wherein said method comprises attenuating a second audio signal in response to both of the first direction indication and the second direction indication indicating a corresponding direction of arrival that intersects the midsagittal plane, and

wherein the second audio signal includes audio-frequency energy from a signal produced by at least one microphone among the first and second pairs.

12. The method of claim 1, wherein said controlling the gain comprises attenuating the audio signal in response to both of the first direction indication and the second direction indication indicating a corresponding direction of arrival that intersects the midsagittal plane.

13. The method of claim 12, wherein said method comprises:

mixing a signal that is based on the output signal with a reproduced audio signal to produce a mixed signal, and

driving a loudspeaker that is worn at an ear of the user and is directed at a corresponding eardrum of the user to produce an acoustic signal that is based on the mixed signal.

14. The method of claim 1, wherein said method includes driving a loudspeaker that is worn at an ear of the user and is directed at a corresponding eardrum of the user to produce an acoustic signal that is based on the output signal.

15. The method of claim 1, wherein the first pair is separated from the second pair by at least ten centimeters.

16. An apparatus for audio signal processing, said apparatus comprising:

means for calculating a first direction indication of a direction of arrival, relative to a first pair of microphones, of a first sound component received by the first pair of microphones;

means for calculating a second direction indication of a direction of arrival, relative to a second pair of microphones that is separate from the first pair, of a second sound component received by the second pair of microphones, wherein the first and second pair of microphones are worn by a user; and

means for controlling a gain of an audio signal using the first and second direction indications to produce an output signal,

wherein the microphones of the first pair are located at a first side of the midsagittal plane of a head of the user,

wherein the microphones of the second pair are located at a second side of the midsagittal plane that is opposite to the first side, and

wherein the means for controlling the gain comprise means for determining whether both of the first direction indication and the second direction indication indicated directions of arrival that intersect the midsagittal plane.

17. The apparatus of claim 16, wherein the audio signal includes audio-frequency energy from a signal produced by at least one microphone among the first and second pairs.

18. The apparatus of claim 16, wherein the audio signal includes audio-frequency energy from a signal produced by a voice microphone, and

wherein the voice microphone is located in a coronal plane of the head of the user that is closer to a central exit point of a voice of the user than at least one microphone of each of the first and second microphone pairs.

19. The apparatus of claim 16, wherein said apparatus comprises means for calculating a plurality of linear prediction coding filter coefficients, based on audio-frequency energy of the output signal.

20. The apparatus of claim 16, wherein said means for calculating the first direction indication includes means for calculating, for each among a plurality of different frequency components of a multichannel signal that is based on signals produced by the first pair of microphones, a difference between a phase of the frequency component in a first channel of the multichannel signal and a phase of the frequency component in a second channel of the multichannel signal.

21. The apparatus of claim 16, wherein the locations of the microphones of the first pair are along a first axis, and

wherein the locations of the microphones of the second pair are along a second axis, and

wherein each among the first and second axes is not more than forty-five degrees from parallel to a line that is orthogonal to the midsagittal plane.

22. The apparatus of claim 21, wherein each among the first and second axes is not more than thirty degrees from parallel to a line that is orthogonal to the midsagittal plane.

23. The apparatus of claim 21, wherein each among the first and second axes is not more than twenty degrees from parallel to a line that is orthogonal to the midsagittal plane.

24. The apparatus of claim 16, wherein said means for controlling the gain comprises means for attenuating the audio signal unless both of the first direction indication and the second direction indication indicate directions of arrival that intersect the midsagittal plane.

25. The apparatus of claim 16, wherein said means for controlling the gain comprises means for attenuating the audio signal in response to at least one among the first and second direction indications indicating a corresponding direction of arrival that is away from the midsagittal plane.

26. The apparatus of claim 25, wherein said apparatus comprises means for attenuating a second audio signal in response to both of the first direction indication and the second direction indication indicating a corresponding direction of arrival that intersects the midsagittal plane, and

wherein the second audio signal includes audio-frequency energy from a signal produced by at least one microphone among the first and second pairs.

27. The apparatus of claim 16, wherein said means for controlling the gain comprises means for attenuating the audio signal in response to both of the first direction indication and the second direction indication indicating a corresponding direction of arrival that intersects the midsagittal plane.

28. The apparatus of claim 27, wherein said apparatus comprises:

means for mixing a signal that is based on the output signal with a reproduced audio signal to produce a mixed signal, and

means for driving a loudspeaker that is worn at an ear of the user and is directed at a corresponding eardrum of the user to produce an acoustic signal that is based on the mixed signal.

29. The apparatus of claim 16, wherein said apparatus includes means for driving a loudspeaker that is worn at an ear of the user and is directed at a corresponding eardrum of the user to produce an acoustic signal that is based on the output signal.

30. The apparatus of claim 16, wherein the first pair is separated from the second pair by at least ten centimeters.

31. An apparatus for audio signal processing, said apparatus comprising:

a first pair of microphones configured to be located, during a use of the apparatus, at a first side of a midsagittal plane of a head of a user;

a second pair of microphones that is separate from the first pair and is configured to be located, during the use of the apparatus, at a second side of the midsagittal plane that is opposite to the first side;

a first direction indication calculator configured to calculate a first indication of a direction of arrival, relative to the first pair of microphones, of a first sound component received by the first pair of microphones;

a second direction indication calculator configured to calculate a second indication of a direction of arrival, relative to the second pair of microphones, of a second sound component received by the second pair of microphones, wherein the first and second pair of microphones are worn by the user; and

a gain control module configured to control a gain of an audio signal using the first and second direction indications to produce an output signal,

wherein the gain control module is further configured to determine whether both of the first direction indication and the second direction indication indicate directions of arrival that intersect the midsagittal plane.

32. The apparatus of claim 31, wherein the audio signal includes audio-frequency energy from a signal produced by at least one microphone among the first and second pairs.

33. The apparatus of claim 31, wherein the audio signal includes audio-frequency energy from a signal produced by a voice microphone, and

wherein the voice microphone is located in a coronal plane of the head of the user that is closer to a central exit point of a voice of the user than at least one microphone of each of the first and second microphone pairs.

34. The apparatus of claim 31, wherein said apparatus comprises an analysis module configured to calculate a plurality of linear prediction coding filter coefficients, based on audio-frequency energy of the output signal.

35. The apparatus of claim 31, wherein said first direction indication calculator is configured to calculate, for each among a plurality of different frequency components of a multichannel signal that is based on signals produced by the first pair of microphones, a difference between a phase of the frequency component in a first channel of the multichannel signal and a phase of the frequency component in a second channel of the multichannel signal.

36. The apparatus of claim 31, wherein the locations of the microphones of the first pair are along a first axis, and

wherein the locations of the microphones of the second pair are along a second axis, and

wherein each among the first and second axes is not more than forty-five degrees from parallel to a line that is orthogonal to the midsagittal plane.

37. The apparatus of claim 36, wherein each among the first and second axes is not more than thirty degrees from parallel to a line that is orthogonal to the midsagittal plane.

38. The apparatus of claim 36, wherein each among the first and second axes is not more than twenty degrees from parallel to a line that is orthogonal to the midsagittal plane.

39. The apparatus of claim 31, wherein said gain control module is configured to attenuate the audio signal unless both of the first direction indication and the second direction indication indicate directions of arrival that intersect the midsagittal plane.

40. The apparatus of claim 31, wherein said gain control module is configured to attenuate the audio signal in response to at least one among the first and second direction indications indicating a corresponding direction of arrival that is away from the midsagittal plane.

41. The apparatus of claim 40, wherein said apparatus comprises a second gain control module configured to attenuate a second audio signal in response to both of the first direction indication and the second direction indication indicating a corresponding direction of arrival that intersects the midsagittal plane, and

wherein the second audio signal includes audio-frequency energy from a signal produced by at least one microphone among the first and second pairs.

42. The apparatus of claim 31, wherein said gain control module is configured to attenuate the audio signal in response to both of the first direction indication and the second direction indication indicating a corresponding direction of arrival that intersects the midsagittal plane.

43. The apparatus of claim 42, wherein said apparatus comprises:

a mixer configured to mix a signal that is based on the output signal with a reproduced audio signal to produce a mixed signal, and

an audio output stage configured to drive a loudspeaker that is worn at an ear of the user and is directed at a corresponding eardrum of the user to produce an acoustic signal that is based on the mixed signal.

44. The apparatus of claim 31, wherein said apparatus includes an audio output stage configured to drive a loudspeaker that is worn at an ear of the user and is directed at a corresponding eardrum of the user to produce an acoustic signal that is based on the output signal.

45. The apparatus of claim 31, wherein the first pair is separated from the second pair by at least ten centimeters.

46. A non-transitory computer-readable storage medium having tangible features that when read by a machine cause the machine to:

calculate a first direction indication of a direction of arrival, relative to a first pair of microphones, of a first sound component received by the first pair of microphones;

calculate a second direction indication of a direction of arrival, relative to a second pair of microphones that is separate from the first pair, of a second sound component received by the second pair of microphones, wherein the first and second pair of microphones are worn by a user; and

control a gain of an audio signal, using the first and second direction indications, to produce an output signal,

wherein the microphones of the first pair are located at a first side of the midsagittal plane of a head of the user,

wherein the microphones of the second pair are located at a second side of the midsagittal plane that is opposite to the first side, and

wherein controlling the gain comprises determining whether both of the first direction indication and the second direction indication indicate directions of arrival that intersect the midsagittal plain.