Binaural beamforming microphone array

Patent metadata

Field	Value
Publication number	US-11546691-B2
Application number	US-202017273237-A
Country	US
Kind code	B2
Filing date	Jun 4, 2020
Priority date	Jun 4, 2020
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

A binaural beamformer comprising two beamforming filters may be communicatively coupled to a microphone array to generates two beamforming outputs, one for the left ear and the other for the right ear. The beamforming filters may be configured in such a way that they are orthogonal to each other to make white noise components in the binaural outputs substantially uncorrelated and desired signal components in the binaural outputs highly correlated. As a result, the human auditory system may better separate the desired signal from white noise and intelligibility of the desired signal may be improved.

First claim

The invention claimed is:

1. A method implemented by a processing device communicatively coupled to a microphone array comprising a number M of microphones, where M is greater than one, the method comprising:
receiving, from the microphone array, an audio input signal comprising a source audio signal and a noise signal;
filtering, by the processing device executing a first beamformer filter associated with the microphone array, the audio input signal to generate a first audio output signal designated for a first aural receiver, the first audio output signal comprising a first audio signal component corresponding to the source audio signal and a first noise component corresponding to the noise signal;
filtering, by the processing device executing a second beamformer filter associated with the microphone array, the audio input signal to generate a second audio output signal designated for a second aural receiver, the second audio output comprising a second audio signal component corresponding to the source audio and a second noise component corresponding to the noise signal, wherein the filtering performed through the second beamformer filter is substantially orthogonal to the filtering performed through the first beamformer filter, resulting in that the first noise component is substantially uncorrelated with the second noise components; and
providing the first audio output signal through a first signal link to the first aural receiver and the second audio output signal through a second signal link to the second aural receiver, wherein the first signal link is separate from the second signal link.

2. The method of claim 1 , wherein the first and second audio signal components are substantially in phase with each other and wherein the first and second noise components have a random phase relationship with each other.

3. The method of claim 1 , wherein an interaural coherence value between the first and second noise components has a value substantially equal to zero.

4. The method of claim 1 , wherein an interaural coherence value between the first and second audio signal components is substantially equal to one.

5. The method of claim 1 , wherein the first audio signal component is substantially correlated with the second audio signal component.

6. The method of claim 1 , wherein an inner product of a first vector value representing the first beamformer filter and a second vector value representing the second beamformer filter is substantially equal zero.

7. The method of claim 1 , wherein providing the first audio output signal to the first aural receiver and the second audio output signal to the second aural receiver comprises simultaneously providing the first audio output signal to the first aural receiver and the second audio output signal to the second aural receiver.

8. The method of claim 1 , wherein the first aural receiver is configured to the provide the first audio output to the left ear of a user and the second aural receiver is configured to provide the second audio output to the right ear of the user.

9. The method of claim 1 , further comprising applying beamforming to the source audio signal to create a beampattern that is substantially frequency-invariant.

10. The method of claim 1 , wherein the filtering performed through at least one of the first beamformer filter or the second beamformer filter maximizes a directivity factor associated with the microphone array under a distortionless constraint.

11. A microphone array system, comprising:
a data store; and
a processing device, communicatively coupled to the data store and to a number M of microphones of a microphone array, where M is greater than one, to:
receive, from the microphone array, an audio input signal comprising a source audio signal and a noise signal;
filter, by executing a first beamformer filter associated with the microphone array, the audio input signal to generate a first audio output signal designated for a first aural receiver, the first audio output comprising a first audio signal component corresponding to the source audio signal and a first noise component corresponding to the noise signal;
filter, by executing a second beamformer filter associated with the microphone array, the audio input signal to generate a second audio output designated for a second aural receiver, the second audio output signal comprising a second audio signal component corresponding to the source audio and a second noise component corresponding to the noise signal, wherein the filtering performed through the second beamformer filter is substantially orthogonal to the filtering performed through the first beamformer filter, resulting in that the first noise component is substantially uncorrelated with the second noise components; and
provide the first audio output signal through a first signal link to the first aural receiver and the second audio output signal through a second signal link to the second aural receiver, wherein the first signal link is separate from the second signal link.

12. The microphone array system of claim 11 , wherein the first and second audio signal components are substantially in phase with each other and wherein the first and second noise components have a random phase relationship with each other.

13. The microphone array system of claim 11 , wherein an interaural coherence value between the first and second noise components has a value substantially equal to zero.

14. The microphone array system of claim 11 , wherein an interaural coherence value between the first and second audio signal components is substantially equal to one.

15. The microphone array system of claim 11 , wherein the first audio signal component is substantially correlated with the second audio signal component.

16. The microphone array system of claim 11 , wherein an inner product of a first vector value representing the first beamformer filter and a second vector value representing the second beamformer filter is substantially equal zero.

17. The microphone array system of claim 11 , wherein to provide the first audio output signal to the first aural receiver and the second audio output signal to the second aural receiver, the processing device is to simultaneously provide the first audio output signal to the first aural receiver and the second audio output signal to the second aural receiver.

18. The microphone array system of claim 11 , wherein the first aural receiver is configured to the provide the first audio output to the left ear of a user and the second aural receiver is configured to provide the second audio output to the right ear of the user.

19. The microphone array system of claim 11 , wherein the processing device is further configured to apply beamforming to the source audio signal to create a beampattern that is substantially frequency-invariant.

20. The microphone array system of claim 11 , wherein at least one of the first beamformer filter or the second beamformer filter executed by the processing device maximizes a directivity factor associated with the microphone array under a distortionless constraint.

21. A non-transitory machine-readable storage medium storing instructions which, when executed, cause a processing device to:
receive, from a microphone array of M microphones, an audio input signal comprising a source audio signal and a noise signal, where M is greater than one;
filter, by executing a first beamformer filter associated with the microphone array, the audio input signal to generate a first audio output

Assignees

• Univ Northwestern Polytechnical

Inventors

• Chen Jingdong
• Wang Yuzhu
• Jin Jilu
• Huang Gongping
• Benesty Jacob

Classifications

• G10K11/17881

  the reference signal being an acoustic signal, e.g. recorded with a microphone · CPC title

• H04R5/027

  Spatial or constructional arrangements of microphones, e.g. in dummy heads · CPC title

• H04R3/12

  for distributing signals to two or more loudspeakers {(specially adapted for hearing aids H04R25/407)} · CPC title

• G10L21/0208

  Noise filtering · CPC title

• G10L2021/02166

  Microphone arrays; Beamforming · CPC title