Methods, apparatuses and computer program products for facilitating directional audio capture with multiple microphones

• US 9,955,263 B2
• Filed: 12/01/2015
• Issued: 04/24/2018
• Est. Priority Date: 10/15/2012
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Technologies Oy (Nokia Corporation)
• Inventors: Huttunen, Anu Hannele, Makinen, Jorma Juhani
• Primary Examiner(s): Gauthier, Gerald
• Application Number:
  US14/956,005
• Publication Number:
  US 20160088392A1
• Time in Patent Office: 875 Days
• Field of Search: 340 1334, 340902, 348 1408, 4555756, 600 25, 702190, 37940602, 379454, 381 26, 381 711, 381 7111, 381 86, 381 92, 381 941, 381 943, 381 949, 381300, 381313
• CPC Class Codes: H04R 1/265 of microphones
• CPC Class Codes: H04R 1/326 for microphones H04R1/34 and H04R1/40 take precedence
• CPC Class Codes: H04R 2201/405 Non-uniform arrays of transducers or a plurality of uniform arrays with different transducer spacing
• CPC Class Codes: H04R 2203/12 Beamforming aspects for stereophonic sound reproduction with loudspeaker arrays
• CPC Class Codes: H04R 2430/03 Synergistic effects of band splitting and sub-band processing
• 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 5/027 Spatial or constructional arrangements of microphones, e.g. in dummy heads

Abstract

An apparatus for providing directional audio capture may include a processor and memory storing executable computer program code that cause the apparatus to at least perform operations including assigning at least one beam direction, among a plurality of beam directions, in which to direct directionality of an output signal of one or more microphones. The computer program code may further cause the apparatus to divide microphone signals of the microphones into selected frequency subbands wherein an analysis performed. The computer program code may further cause the apparatus to select at least one set of microphones of the apparatus for selected frequency subbands. The computer program code may further cause the apparatus to optimize the assigned at least one beam direction by adjusting a beamformer parameter(s) based on the selected set of microphones and at least one of the selected frequency subbands. Corresponding methods and computer program products are also provided.

Claims

1. An apparatus comprising:

a directional audio capture module; and

a plurality of microphones positioned at predetermined locations of the apparatus;

the directional audio capture module is configured to;

assign at least one beam direction, among a plurality of beam directions, in which to direct directionality of an output signal of one or more of the microphones;

select a first set of microphones comprising at least two microphones, of the plurality of microphones, for a first frequency band;

select a second set of microphones comprising at least two microphones, of the plurality of microphones, for a second frequency band; and

optimize the output signal for the assigned at least one beam direction by adjusting at least one beamformer parameter based on the selected first and second sets of microphones, wherein respective sets of microphone signals for the first and second frequency bands are processed by the adjusted at least one beamformer parameter to optimize the output signal for the assigned at least one beam direction.

2. The apparatus of claim 1, wherein the directional audio capture module is further configured to:

select the first set of microphones and the second set of microphones based in part on a distance between the microphones of the first set and the microphones of the second set.

3. The apparatus of claim 1, wherein:

at least a subset of the plurality of microphones support one or more of a plurality of applications comprising stereo recording, directional mono recording, surround sound recording, directional stereo recording, telephony processing or speech recognition processing.

4. The apparatus of claim 1, wherein the directional audio capture module is further configured to:

select an alternative set of microphones, of the plurality of microphones, to replace at least one of the first set of microphones or the second set of microphones in an instance in which interference is detected affecting the first frequency band or the second frequency band.

5. The apparatus of claim 1, wherein the directional audio capture module is further configured to:

detect that at least one of the first frequency band or the second frequency band comprises a low frequency band in response to detecting that a respective frequency is below a frequency threshold.

6. The apparatus of claim 1, wherein the directional audio capture module is further configured to:

detect that at least one of the first frequency band or the second frequency band comprises a high frequency band in response to detecting that a respective frequency is greater than or equal to a frequency threshold.

7. The apparatus of claim 1, wherein:

at least one of the first set of microphones or the second set of microphones are utilized for a plurality of frequency bands.

8. The apparatus of claim 1, further comprising at least one processor wherein:

the at least one processor or the directional audio capture module is further configured to;

optimize each beam direction, of the plurality of beam directions, and each frequency band, among a plurality of frequency bands, independently.

9. The apparatus of claim 1, wherein:

the at least one beamformer parameter comprises one or more beamformer filter coefficients.

10. The apparatus of claim 1, wherein the directional audio capture module is further configured to:

select the first set of microphones by selecting the first set of microphones comprising a large mutual distance, that exceeds a threshold distance, between the microphones of the first set for the first frequency band, comprising a low frequency band that is below a frequency threshold.

11. The apparatus of claim 10, wherein the directional audio capture module is further configured to:

select the second set of microphones by selecting the second set of microphones comprising a small mutual distance, that is below the threshold distance, between the microphones of the second set for the second frequency band, comprising a high frequency band that is greater than or equal to the frequency threshold.

12. The apparatus of claim 11, wherein:

the threshold distance comprises a distance of ten centimeters.

13. The apparatus of claim 11, wherein:

the microphones of the first set, comprising the large mutual distance between the microphones of the first set, provide a higher level of directionality for audio recordings than the microphones of the second set, comprising the small mutual distance between the microphones of the second set.

14. The apparatus of claim 11, wherein the directional audio capture module is further configured to:

utilize the microphones of the first set in the low frequency band and the microphones of the second set in the high frequency band to support a hands-free telephony application or another audio processing application.

15. The apparatus of claim 14, wherein the directional audio capture module is further configured to:

block low frequency disturbance in a null direction of the output signal for the assigned at least one beam direction.

16. A method comprising:

assigning, via a directional audio capture module of an apparatus, at least one beam direction, among a plurality of beam directions, in which to direct directionality of an output signal of one or more microphones of a plurality of microphones positioned at predetermined locations of the apparatus;

selecting, via the directional audio capture module, a first set of microphones comprising at least two microphones, of the plurality of microphones, for a first frequency band;

selecting, via the directional audio capture module, a second set of microphones comprising at least two microphones, of the plurality of microphones, for a second frequency band; and

optimizing, via the directional audio capture module, the assigned at least one beam direction by adjusting at least one beamformer parameter based on the selected first and second sets of microphones, wherein respective sets of microphone signals for the first and second frequency bands are processed by the adjusted at least one beamformer parameter to optimize the output signal for the assigned at least one beam direction.

17. The method of claim 16, further comprising:

selecting, via the directional audio capture module, the first set of microphones and the second set of microphones based in part on a distance between the microphones of the first set and the microphones of the second set.

18. The method of claim 16, further comprising:

supporting, via at least a subset of the plurality of microphones, one or more of a plurality of applications comprising stereo recording, directional mono recording, surround sound recording, directional stereo recording, telephony processing or speech recognition processing.

19. The method of claim 16, further comprising:

selecting, via the directional audio capture module, an alternative set of microphones, of the plurality of microphones, to replace at least one of the first set of microphones or the second set of microphones in an instance in which interference is detected affecting the first frequency band or the second frequency band.

20. The method of claim 16, further comprising:

detecting, via the directional audio capture module, that at least one of the first frequency band or the second frequency band comprises a low frequency band in response to detecting that a respective frequency is below a frequency threshold.

21. The method of claim 16, further comprising:

detecting, via the directional audio capture module, that at least one of the first frequency band or the second frequency band comprises a high frequency band in response to detecting that a respective frequency is greater than or equal to a frequency threshold.

22. The method of claim 16, wherein:

at least one of the first set of microphones or the second set of microphones are utilized for a plurality of frequency bands.

23. The method of claim 16, further comprising:

optimizing, via a processor of the apparatus or the directional audio capture module, each beam direction, of the plurality of beam directions, and each frequency band, among a plurality of frequency bands, independently.

24. The method of claim 16, wherein:

the at least one beamformer parameter comprises one or more beamformer filter coefficients.

25. The method of claim 16, wherein:

selecting the first set of microphones further comprises selecting the first set of microphones comprising a large mutual distance, that exceeds a threshold distance, between the microphones of the first set for the first frequency band, comprising a low frequency band that is below a frequency threshold.

26. The method of claim 25, wherein:

selecting the second set of microphones further comprises selecting the second set of microphones comprising a small mutual distance, that is below the threshold distance, between the microphones of the second set for the second frequency band, comprising a high frequency band that is greater than or equal to the frequency threshold.

27. The method of claim 26, wherein:

the threshold distance comprises a distance of ten centimeters.

28. The method of claim 26, wherein:

the microphones of the first set, comprising the large mutual distance between the microphones of the first set, provide a higher level of directionality for audio recordings than the microphones of the second set, comprising the small mutual distance between the microphones of the second set.

29. The method of claim 26, further comprising:

utilizing the microphones of the first set in the low frequency band and the microphones of the second set in the high frequency band to support a hands-free telephony application or another audio processing application.

30. The method of claim 29, further comprising:

blocking low frequency disturbance in a null direction of the output signal for the assigned at least one beam direction.

31. A computer program product comprising at least one non-transitory computer-readable storage medium having computer-executable program code instructions stored therein, the computer-executable program code instructions comprising:

program code instructions configured to assign at least one beam direction, among a plurality of beam directions, in which to direct directionality of an output signal of one or more microphones of a plurality of microphones positioned at predetermined locations of an apparatus;

program code instructions configured to select a first set of microphones comprising at least two microphones, of the plurality of microphones, for a first frequency band;

program code instructions configured to select a second set of microphones comprising at least two microphones, of the plurality of microphones, for a second frequency band; and

program code instructions configured to optimize the output signal for the assigned at least one beam direction by adjusting at least one beamformer parameter based on the selected first and second sets of microphones, wherein respective sets of microphone signals for the first and second frequency bands are processed by the adjusted at least one beamformer parameter to optimize the output signal for the assigned at least one beam direction.

32. The computer program product of claim 31, further comprising:

program code instructions configured to select the first set of microphones and the second set of microphones based in part on a distance between the microphones of the first set and the microphones of the second set.

33. The computer program product of claim 31, further comprising:

program code instructions configured to support, via at least a subset of the plurality of microphones, one or more of a plurality of applications comprising stereo recording, directional mono recording, surround sound recording, directional stereo recording, telephony processing or speech recognition processing.

34. The computer program product of claim 31, further comprising:

program code instructions configured to select an alternative set of microphones, of the plurality of microphones, to replace at least one of the first set of microphones or the second set of microphones in an instance in which interference is detected affecting the first frequency band or the second frequency band.

35. The computer program product of claim 31, wherein:

the at least one beamformer parameter comprises one or more beamformer filter coefficients.

36. The computer program product of claim 31, wherein:

select the first set of microphones further comprises selecting the first set of microphones comprising a large mutual distance, that exceeds a threshold distance, between the microphones of the first set for the first frequency band, comprising a low frequency band that is below a frequency threshold.

37. The computer program product of claim 36, wherein:

select the second set of microphones further comprises selecting the second set of microphones comprising a small mutual distance, that is below the threshold distance, between the microphones of the second set for the second frequency band, comprising a high frequency band that is greater than or equal to the frequency threshold.

38. The computer program product of claim 37, wherein:

the threshold distance comprises a distance of ten centimeters.

39. The computer program product of claim 37, wherein:

the microphones of the first set, comprising the large mutual distance between the microphones of the first set, provide a higher level of directionality for audio recordings than the microphones of the second set, comprising the small mutual distance between the microphones of the second set.

40. The computer program product of claim 37, further comprising:

program code instructions configured to utilize the microphones of the first set in the low frequency band and the microphones of the second set in the high frequency band to support a hands-free telephony application or another audio processing application.

41. The computer program product of claim 40, further comprising:

program code instructions configured to block low frequency disturbance in a null direction of the output signal for the assigned at least one beam direction.