Head wearable acoustic system with noise canceling microphone geometry apparatuses and methods

• US 10,306,389 B2
• Filed: 10/18/2015
• Issued: 05/28/2019
• Est. Priority Date: 03/13/2013
• Status: Active Grant

• Current Assignee: Solos Technology Limited
• Original Assignee: Kopin Corporation
• Inventors: Fan, Dashen, Chen, Xi, Bao, Hua, Davis, Eric Frederic
• Primary Examiner(s): Fischer, Mark
• Application Number:
  US14/886,077
• Publication Number:
  US 20160112817A1
• Time in Patent Office: 1,318 Days
• CPC Class Codes: G10L 2021/02165 Two microphones, one receiving mainly the noise signal and the other one mainly the speech signal
• CPC Class Codes: G10L 2021/02166 Microphone arrays; Beamforming
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10
• CPC Class Codes: H04R 1/028 associated with devices performing functions other than acoustics, e.g. electric candles
• CPC Class Codes: H04R 1/326 for microphones H04R1/34 and H04R1/40 take precedence
• CPC Class Codes: H04R 2203/12 Beamforming aspects for stereophonic sound reproduction with loudspeaker arrays
• CPC Class Codes: H04R 2410/01 Noise reduction using microphones having different directional characteristics
• CPC Class Codes: H04R 29/004 for microphones H04R29/007 takes precedence
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

Systems and methods are described to extract desired audio from an apparatus that is worn on a user'"'"'s head. The apparatus includes a head wearable device. A first microphone is positioned on the head wearable device to receive a voice signal from the user A first signal from the first microphone is input as a main channel to a noise cancellation unit. A second microphone is coupled to the head wearable device. A first acoustic distance between the first microphone and the user'"'"'s mouth is less than a second acoustic distance between the second microphone and the user'"'"'s mouth when the head wearable device is on the user'"'"'s head. A second signal from the second microphone is input as a reference channel to the noise cancellation unit. A first signal-to-noise ratio of the first signal is larger than a second signal-to-noise ratio of the second signal.

Claims

1. An apparatus to be worn on a user'"'"'s head, comprising:

a head wearable device, the head wearable device is configured to be worn on the user'"'"'s head;

a first microphone, the first microphone is coupled to the head wearable device, and is positioned on the head wearable device to receive a voice signal from the user when the head wearable device is on the user'"'"'s head, a first signal from the first microphone is to be input as a main channel to a two-stage noise cancellation unit; and

a second microphone, the second microphone is coupled to the head wearable device, a first acoustic distance between the first microphone and the user'"'"'s mouth is less than a second acoustic distance between the second microphone and the user'"'"'s mouth when the head wearable device is on the user'"'"'s head, a second signal from the second microphone is to be input as a reference channel to the two-stage noise cancellation unit, wherein a first signal-to-noise ratio of the first signal from the first microphone is larger than a second signal-to-noise ratio of the second signal from the second microphone, and the two-stage noise cancellation unit is configured to reduce noise from any arrival angle of desired audio, where the arrival angle is relative to an axis passing through the first microphone and the second microphone.

2. The apparatus of claim 1, further comprising:

a wireless communication system, the wireless communication system is coupled to the head wearable device and is electrically coupled to the first microphone and to the second microphone.

3. The apparatus of claim 2, wherein the wireless communication system is compatible with a BLUETOOTH®

communication protocol.

4. The apparatus of claim 1, further comprising:

an adaptive noise cancellation unit, the adaptive noise cancellation unit to receive the first signal from the first microphone and the second signal from the second microphone, the adaptive noise cancellation unit reduces undesired audio from the main channel;

a single channel noise cancellation unit, an output signal from the adaptive noise cancellation unit is input to the single channel noise cancellation unit, the single channel noise cancellation unit reduces undesired audio from the output signal to provide mostly desired audio; and

a filter control, the filter control to create a control signal from a normalized main signal, the apparatus normalizes the first signal by the second signal to create the normalized main signal, the control signal is electrically coupled to the adaptive noise cancellation unit and the single channel noise cancellation unit to control filtering in the adaptive noise cancellation unit and to control filtering in the single channel noise cancellation unit.

5. The apparatus of claim 4, further comprising:

a beamformer, the beamformer is configured to receive the first signal from the first microphone and the second signal from the second microphone and to provide a main signal on the main channel and at least one reference signal on at least one reference channel to the adaptive noise cancellation unit and to the filter control.

6. The apparatus of claim 4, wherein the head wearable device is selected from the group consisting of eye glasses, goggles, a visor, a helmet, and a user defined head wearable device.

7. The apparatus of claim 4, wherein at least one of the adaptive noise cancellation unit, the single channel noise cancellation unit, and the filter control are part of an integrated circuit and the integrated circuit is coupled to the head wearable device.

8. The apparatus of claim 4, wherein the adaptive noise cancellation unit, the single channel noise cancellation unit, and the filter control are part of an integrated circuit and the integrated circuit is coupled to the head wearable device.

9. The apparatus of claim 1, wherein the first microphone and the second microphone have substantially omni-directional response patterns.

10. The apparatus of claim 9, wherein a first location for the first microphone and a second location for the second microphone provide a signal-to-noise ratio difference.

11. The apparatus of claim 10, wherein the signal-to-noise ratio difference is established during design of the apparatus from a value of a curve selected from the group consisting of FIG. 3C, FIG. 4C, FIG. 5C, and a user defined curve.

12. The apparatus of claim 1, wherein the first microphone has a first response pattern and a first response pattern main sensitivity axis and the second microphone has a second response pattern and a second response pattern main sensitivity axis, the second response pattern is different from the first response pattern and the second response pattern main sensitivity axis is misaligned with a direction of desired audio, wherein a signal-to-noise ratio difference between the first microphone and the second microphone is enhanced by the misalignment.

13. The apparatus of claim 12, wherein the first response pattern is selected from the group consisting of omni-directional, cardioid, bidirectional, super cardioid, hyper cardioid, and user defined, and the second response pattern is selected from the group consisting of omni-directional, cardioid, bidirectional, super cardioid, hyper cardioid, and user defined.

14. The apparatus of claim 12, further comprising:

an adaptive noise cancellation unit, the adaptive noise cancellation unit to receive the first signal from the first microphone and the second signal from the second microphone, the adaptive noise cancellation unit to reduce undesired audio from the main channel;

a single channel noise cancellation unit, an output signal from the adaptive noise cancellation unit is input to the single channel noise cancellation unit, the single channel noise cancellation unit reduces undesired audio from the output signal to provide mostly desired audio; and

a filter control, the filter control to create a control signal from a normalized main signal, the apparatus normalizes the first signal by the second signal to create the normalized main signal, the control signal is electrically coupled to the adaptive noise cancellation unit and the single channel noise cancellation unit to control filtering in the adaptive noise cancellation unit and to control filtering in the single channel noise cancellation unit.

15. The apparatus of claim 12, wherein the second microphone is positioned on the head wearable device at substantially any location.

16. The apparatus of claim 15, wherein the first microphone and the second microphone are substantially co-located.

17. The apparatus of claim 1, further comprising:

a beamformer, the beamformer is configured to receive the first signal and the second signal and to output a main signal on a main channel and at least one reference signal on at least one reference channel.

18. The apparatus of claim 17, further comprising:

a third microphone, the third microphone is input into the beamformer, the beamformer configured to output a main signal and two reference signals.

19. An apparatus to be worn on a user'"'"'s head, comprising:

a head wearable device, the head wearable device is configured to be worn on the user'"'"'s head;

a first microphone, the first microphone has a first response pattern and the first response pattern has a first major response axis, the first microphone is coupled to the head wearable device, the first microphone is positioned on the head wearable device to receive a voice signal from the user;

a second microphone, the second microphone is coupled to the head wearable device, the second microphone and the first microphone are separated by a distance on the head wearable device such that a first acoustic distance between the first microphone and the user'"'"'s mouth is less than a second acoustic distance between the second microphone and the user'"'"'s mouth when the head wearable device is on the user'"'"'s head;

a beamformer, the beamformer is configured to receive input signals from at least the first microphone and the second microphone and to provide a main signal on a main channel and at least one reference signal on at least one reference channel;

an adaptive noise cancellation unit, the adaptive noise cancellation unit is coupled to receive the main signal and the at least one reference signal from the beamformer, the adaptive noise cancellation unit to reduce a first amount of undesired audio from the main signal to form a filtered output signal;

a filter control, the filter control is coupled to the beamformer, the filter control to create a control signal from the main signal and the at least one reference signal to control reduction of undesired audio; and

a single channel noise reduction unit, the single channel noise reduction unit is coupled to receive the filtered output signal and is coupled to the filter control, the single channel noise reduction unit reduces a second amount of undesired audio from the filtered output signal to provide mostly desired audio in the main signal.

20. The apparatus of claim 19, wherein a first location for the first microphone and a second location for the second microphone provide a signal-to-noise ratio difference between the first microphone and second microphone.

21. The apparatus of claim 20, wherein the signal-to-noise ratio difference is established during design of the apparatus from a value of a curve selected from the group consisting of FIG. 3C, FIG. 4C, FIG. 5C, and a user defined curve.

22. An apparatus to be worn on a users head, comprising:

a head wearable device, the head wearable device having a first microphone and a second microphone;

a data processing system, the data processing system is configured to process acoustic signals, wherein the acoustic signals from the first microphone and the second microphone, are input to the data processing system and the data processing system is contained within the head wearable device; and

a computer readable medium containing executable computer program instructions, which when executed by the data processing system, cause the data processing system to perform a method comprising;

receiving a main signal and a reference signal;

producing a filter control signal from the main signal and the reference signal, wherein the apparatus normalizes the main signal by the reference signal during the producing;

applying a first stage of filtering with the main signal and the reference signal input to a multi-channel filter to reduce a first amount of undesired audio from the main signal, wherein the filter control signal is provided to the first stage of filtering and is used by the first stage of filtering to separate desired audio from undesired audio during the applying; and

applying a second stage of filtering to an output of the first stage to further reduce undesired audio from the main signal, the filter control signal is provided to the second stage of filtering and is used by the second stage of filtering to separate desired audio from undesired audio in the second stage, the second stage outputs a main signal which is mostly desired audio.

23. The apparatus of claim 22, wherein in the method performed by the data processing system, the applying the first stage further comprising:

controlling adaptation of the multi-channel filter with the filter control signal, wherein the filter control signal utilizes a combination of the main signal and the reference signal.

24. The apparatus of claim 22, wherein in the method performed by the data processing system, the method further comprising:

beamforming with signals from a number of microphone channels to create the main signal and the reference signal.

25. The apparatus of claim 24, wherein the first microphone is positioned on the head wearable device to receive a voice signal from the user and the second microphone is positioned on the head wearable device at substantially any location.

26. The apparatus of claim 24, wherein the second microphone and the first microphone are separated by a distance on the head wearable device such that a first acoustic distance between the first microphone and the users mouth is less than a second acoustic distance between the second microphone and the user'"'"'s mouth.

27. The apparatus of claim 22, wherein a second microphone has a second response pattern and a second response pattern main sensitivity axis, a first microphone has a first response pattern and a first response pattern main sensitivity axis and the second response pattern is different from the first response pattern and the second response pattern main sensitivity axis is misaligned with a direction of desired audio, wherein a signal-to-noise ratio difference between the first microphone and the second microphone is enhanced by the misalignment.

28. The apparatus of claim 27, wherein the first response pattern is omni-directional and the second response pattern is cardioid.

29. The apparatus of claim 27, wherein the first response pattern is selected from the group consisting of omni-directional, cardioid, bidirectional, super cardioid, hyper cardioid, and user defined, and the second response pattern is selected from the group consisting of omni-directional, cardioid, bidirectional, super cardioid, hyper cardioid, and user defined.

30. A method, comprising:

locating a main microphone channel at a first location on a head wearable device, the main microphone channel has a first signal-to-noise ratio when the head wearable device is worn on a user'"'"'s head and desired audio is received on the main microphone channel and the desired audio originated from the users mouth;

locating a reference microphone channel at a second location on the head wearable device, the reference microphone channel has a second signal-to-noise ratio when desired audio is received on the reference microphone channel and the desired audio received on the reference microphone channel originated from the user'"'"'s mouth; and

providing a signal-to-noise ratio difference between the main microphone channel and the reference microphone channel to a first stage of a two-stage linear noise cancellation system when acoustic signals are received by the main microphone channel and the reference microphone channel, wherein the two-stage linear noise cancellation system is coupled to the head wearable device.

31. The method of claim 30, further comprising:

using a normalized main microphone channel signal to control the noise cancellation system, wherein the normalized main microphone channel signal is obtained by normalizing the main microphone channel signal by the reference microphone channel signal.

32. The method of claim 30, wherein at least one of a main microphone and a reference microphone has a directivity pattern different from omni-directional.

33. The method of claim 30, further comprising:

beamforming to provide the main microphone channel and the reference microphone channel, wherein the beamforming contributes to a signal-to-noise ratio difference between the main microphone channel and the reference microphone channel.

34. The method of claim 30, wherein the main microphone channel and the reference microphone channel are substantially co-located.

35. An apparatus to be worn on a user'"'"'s head, comprising:

a head wearable device, the head wearable device is configured to be worn on the user'"'"'s head;

a first microphone, the first microphone is coupled to the head wearable device, and is positioned on the head wearable device to receive a voice signal from the user when the head wearable device is on the user'"'"'s head, a first signal from the first microphone is to be input as a main channel to a noise cancellation unit;

a second microphone, the second microphone is coupled to the head wearable device, a first acoustic distance between the first microphone and the user'"'"'s mouth is less than a second acoustic distance between the second microphone and the user'"'"'s mouth when the head wearable device is on the user'"'"'s head, a second signal from the second microphone is to be input as a reference channel to the noise cancellation unit, wherein a first signal-to-noise ratio of the first signal from the first microphone is larger than a second signal-to-noise ratio of the second signal from the second microphone;

an adaptive noise cancellation unit, the adaptive noise cancellation unit to receive the first signal from the first microphone and the second signal from the second microphone, the adaptive noise cancellation unit reduces undesired audio from the main channel;

a single channel noise cancellation unit, an output signal from the adaptive noise cancellation unit is input to the single channel noise cancellation unit, the single channel noise cancellation unit reduces undesired audio from the output signal to provide mostly desired audio; and

a filter control, the filter control to create a control signal from a normalized main signal, the apparatus normalizes the first signal by the second signal to create the normalized main signal, the control signal is electrically coupled to the adaptive noise cancellation unit and the single channel noise cancellation unit to control filtering in the adaptive noise cancellation unit and to control filtering in the single channel noise cancellation unit.

36. The apparatus of claim 35, further comprising:

a beamformer, the beamformer is configured to receive the first signal from the first microphone and the second signal from the second microphone and to provide a main signal on the main channel and at least one reference signal on at least one reference channel to the adaptive noise cancellation unit and to the filter control.

37. The apparatus of claim 35, wherein the head wearable device is selected from the group consisting of eye glasses, goggles, a visor, a helmet, and a user defined head wearable device.

38. The apparatus of claim 35, wherein at least one of the adaptive noise cancellation unit, the single channel noise cancellation unit, and the filter control are part of an integrated circuit and the integrated circuit is coupled to the head wearable device.

39. The apparatus of claim 35, wherein the adaptive noise cancellation unit, the single channel noise cancellation unit, and the filter control are part of an integrated circuit and the integrated circuit is coupled to the head wearable device.

40. A method, comprising:

locating a main microphone channel at a first location on a head wearable device, the main Microphone channel has a first signal-to-noise ratio when the head wearable device is worn on a user'"'"'s head and desired audio is received on the main microphone channel and the desired audio originated from the user'"'"'s mouth;

locating a reference microphone channel at a second location on the head wearable device, the reference microphone channel has a second signal-to-noise ratio when desired audio is received on the reference microphone channel and the desired audio received on the reference microphone channel originated from the user'"'"'s mouth;

providing a signal-to-noise ratio difference between the main microphone channel and the reference microphone channel to a first stage of a two-stage noise cancellation system when acoustic signals are received by the main microphone channel and the reference microphone channel, wherein the noise cancellation system is coupled to the head wearable device; and

using a normalized main microphone channel signal to control the noise cancellation system, wherein the normalized main microphone channel signal is obtained by normalizing the main microphone channel signal by the reference microphone channel signal.

41. An apparatus to be worn on a user'"'"'s head, comprising:

a head wearable device, the head wearable device is configured to be worn on the users head;

a first microphone, the first microphone is coupled to the head wearable device, and is positioned on the head wearable device to receive a voice signal from the user when the head wearable device is on the user'"'"'s head, a first signal from the first microphone is to be input as a main channel to a two-stage noise cancellation unit; and

a second microphone, the second microphone is coupled to the head wearable device, a first acoustic distance between the first microphone and the user'"'"'s mouth is substantially equivalent to a second acoustic distance between the second microphone and the user'"'"'s mouth when the head wearable device is on the user'"'"'s head, a first response pattern of the first microphone is different from a second response pattern of the second microphone, a second signal from the second microphone is to be input as a reference channel to the two-stage noise cancellation unit, wherein a first signal-to-noise ratio of the first signal from the first microphone is larger than a second signal-to-noise ratio of the second signal from the second microphone, and the two-stage noise cancellation unit is configured to reduce noise from any arrival angle of desired audio, where the arrival angle is relative to an axis passing through the first microphone and the second microphone.

42. The apparatus of claim 41, wherein the first response pattern is omni-directional and the second response pattern is cardioid.