Method and device for acoustic management control of multiple microphones

• US 8,081,780 B2
• Filed: 05/05/2008
• Issued: 12/20/2011
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Staton Techiya, LLC
• Original Assignee: Personics Holdings, Inc.
• Inventors: Goldstein, Steven Wayne, Usher, John, Boillot, Marc Andre, McIntosh, Jason
• Primary Examiner(s): MENZ, DOUGLAS M
• Application Number:
  US12/115,349
• Publication Number:
  US 20090016541A1
• Time in Patent Office: 1,324 Days
• Field of Search: 381/119, 381/328, 381/56
• US Class Current: 381/119
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06
• 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 2460/01 Hearing devices using active noise cancellation
• CPC Class Codes: H04R 2460/07 Use of position data from wide-area or local-area positioning systems in hearing devices, e.g. program or information selection
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

An earpiece (100) and a method (640) for acoustic management of multiple microphones is provided. The method can include capturing an ambient acoustic signal from an Ambient Sound Microphone (ASM) to produce an electronic ambient signal, capturing in an ear canal an internal sound from an Ear Canal Microphone (ECM) to produce an electronic internal signal, measuring a background noise signal, and mixing the electronic ambient signal with the electronic internal signal in a ratio dependent on the background noise signal to produce a mixed signal. The mixing can adjust an internal gain of the electronic internal signal and an external gain of the electronic ambient signal based on the background noise characteristics. The mixing can account for an acoustic attenuation level and an audio content level of the earpiece. Other embodiments are provided.

Claims

1. A method for acoustic management control suitable for use in an earpiece, the method comprising the steps of:

capturing an ambient acoustic signal from at least one Ambient Sound Microphone (ASM) to produce an electronic ambient signal;

capturing in an ear canal an internal sound from at least one Ear Canal Microphone (ECM) to produce an electronic internal signal;

measuring a background noise signal from the electronic ambient signal or the electronic internal signal; and

mixing the electronic ambient signal with the electronic internal signal in a ratio dependent on the background noise signal to produce a mixed signal.

2. The method of claim 1, comprising

increasing an internal gain of the electronic internal signal as background noise levels increase, while

decreasing an external gain of the electronic ambient signal as the background noise levels increase.

3. The method of claim 1, comprising

decreasing an internal gain of the electronic internal signal as background noise levels decrease, while

increasing an external gain of the electronic ambient signal as the background noise levels decrease.

4. The method of claim 1, where the step of mixing includes filtering the electronic ambient signal and the electronic internal signal based on a characteristic of the background noise signal,

where the characteristic is a level of a background noise level, a spectral profile, or an envelope fluctuation.

5. The method of claim 4, wherein the filtering is performed by a High-Pass Filter for the electronic ambient signal and a Low-Pass Filter for the electronic internal signal.

6. The method of claim 4, where filter coefficients for a particular background noise level or a particular spectral profile are loaded from a memory containing pre-defined filter curves.

7. The method of claim 4, where filter coefficients are algorithmically determined for a particular background noise level or a particular spectral profile.

8. The method of claim 4, comprising

at low background noise levels, amplifying the electronic ambient signal from the ASM relative to the electronic internal signal from the ECM in producing the mixed signal,

at medium background noise levels, attenuating low frequencies in the electronic ambient signal and attenuating high frequencies in the electronic internal signal, and

at high background noise levels, amplifying the electronic internal signal from the ECM relative to the electronic ambient signal from the ASM in producing the mixed signal.

9. The method of claim 1, where the mixing is performed in accordance with the relation:

mixed signal=(1−

β

) *electronic ambient signal+(β

)*electronic internal signal, where (1−

β

) is an external gain, (β

) is an internal gain, and the mixing is performed with 0<

β

<

1.

10. The method of claim 1, further comprising

estimating a voice activity level from the electronic internal signal or the electronic ambient signal;

and

scaling the electronic internal signal and the electronic ambient signal in accordance with the voice activity level.

11. The method of claim 10, wherein the mixing is performed by

applying a first gain (G1) to the electronic ambient signal, and

applying a second gain (G2) to the electronic internal signal, where the first gain and the second gain are a function of a background noise level (BNL) and the voice activity level (VAL), according to the relation:

G1=ƒ

(BNL)+ƒ

(VAL) and G2=ƒ

(BNL)+ƒ

(VAL).

12. The method of claim 10, where the step of measuring the background noise signal includes

accounting for an acoustic attenuation level of the earpiece, and

accounting for an audio content level reproduced by an Ear Canal Receiver (ECR) that delivers acoustic audio content to the earpiece.

13. A method for acoustic management control suitable for use in an earpiece, the method comprising the steps of:

capturing an ambient acoustic signal from at least one Ambient Sound Microphone (ASM) to produce an electronic ambient signal;

capturing in an ear canal an internal sound from at least one Ear Canal Microphone (ECM) to produce an electronic internal signal;

detecting a spoken voice signal generated by a wearer of the earpiece from the electronic ambient signal or the electronic internal signal;

measuring a background noise level from the electronic ambient signal or the electronic internal signal when the spoken voice signal is not detected; and

mixing the electronic ambient signal with the electronic internal signal as a function of the background noise level to produce a mixed signal.

14. The method of claim 13, comprising

delivering audio content to the ear canal by way of an Ear Canal Receiver (ECR);

and

adjusting the mixing based on a level of the audio content, the background noise level, and an acoustic attenuation level of the earpiece.

15. The method of claim 14, wherein the audio content is at least one among a phone call, a voice message, a music signal, and the spoken voice signal.

16. The method of claim 13, comprising

suppressing in the mixed signal an echo of the spoken voice signal generated by the wearer of the earpiece, and

producing a modified electronic internal signal containing primarily the spoken voice signal.

17. The method of claim 16, wherein the suppressing is performed by way of a normalized least mean squares algorithm.

18. The method of claim 13, comprising

generating a voice activity level of the spoken voice signal, and

mixing the electronic ambient signal with the electronic internal signal as a function of the voice activity level and the background noise level.

19. An earpiece for acoustic management control, comprising:

an Ambient Sound Microphone (ASM) configured to capture ambient sound and produce an electronic ambient signal;

an Ear Canal Receiver (ECR) to deliver audio content to an ear canal to produce an acoustic audio content;

an Ear Canal Microphone (ECM) configured to capture internal sound in the ear canal and produce an electronic internal signal; and

a processor operatively coupled to the ASM, the ECM and the ECR where the processor is configured to

measure a background noise signal from the electronic ambient signal or the electronic internal signal; and

mix the electronic ambient signal with the electronic internal signal in a ratio dependent on the background noise signal to produce a mixed signal.

20. The earpiece of claim 19, wherein the processor filters the electronic ambient signal and the electronic internal signal based on a characteristic of the background noise signal using filter coefficients stored in a memory or generated algorithmically.

21. The earpiece of claim 20, further comprising a transceiver operatively coupled to the processor to transmit the mixed signal to a communication device, where the processor also plays the mixed signal back to the ECR for loopback listening.

22. The earpiece of claim 20, further comprising an echo suppressor operatively coupled to the processor to suppress an echo of a spoken voice generated by a wearer of the earpiece when speaking.

23. The earpiece of claim 22, further comprising a voice activity detector operatively coupled to the echo suppressor to detect the spoken voice generated by the wearer in the presence of the background noise signal.

24. The earpiece of claim 22, where the processor generates a voice activity level for the spoken voice and applies gains to the electronic ambient signal and the electronic internal signal as a function of a background noise level and the voice activity level.

25. The earpiece of claim 23, further comprising a control unit operatively coupled to the voice activity detector to freeze weights of a Least Mean Squares (LMS) system in the echo suppressor during the speaking of the spoken voice.