Method and system for speech enhancement using a remote microphone

• US 10,332,538 B1
• Filed: 08/17/2018
• Issued: 06/25/2019
• Est. Priority Date: 08/17/2018
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Dusan, Sorin, Biruski, Dubravko
• Primary Examiner(s): Tran, Thang V
• Application Number:
  US15/999,121
• Time in Patent Office: 312 Days
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: G10L 21/0232 Processing in the frequency domain
• CPC Class Codes: H04R 1/1016 Earpieces of the intra-aural type
• CPC Class Codes: H04R 1/1041 Mechanical or electronic switches, or control elements switches in general H01H
• CPC Class Codes: H04R 1/406 microphones
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 25/554 using a wireless connection, e.g. between microphone and amplifier or using Tcoils
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

A speech enhancement system for a remote microphone has a wireless receiver that receives a signal from a first microphone of a remote device. A delay buffer receives a second microphone signal from a second microphone and delays by an adjustable delay. The adjustable delay is based on a difference between a wireless delay and an acoustic delay. A noise suppressor produces an output audio signal for an earpiece speaker, based on the first microphone signal and the adjustable delayed second microphone signal. Other aspects are also described and claimed.

Claims

1. A speech enhancement system for a remote microphone, comprising:

a wireless receiver to receive a wireless signal from a remote device wherein the wireless signal contains a first microphone signal from a first microphone of the remote device;

a first delay buffer to receive a second microphone signal from a second microphone that is contained within a headset housing and to delay the second microphone signal by an adjustable delay, wherein the adjustable delay is based on a difference between a wireless delay and an acoustic delay; and

a noise suppressor to produce an output audio signal for driving an earpiece speaker in the headset housing, based on the first microphone signal and the adjustable delayed second microphone signal.

2. The speech enhancement system of claim 1, further comprising:

the noise suppressor configured to select the first microphone signal, a gain adjusted version of the adjustable delayed second microphone signal, or combine the first microphone signal and the gain adjusted version of the adjusted delayed second microphone signal, to produce the output audio signal.

3. The speech enhancement system of claim 1, further comprising:

the noise suppressor to perform two channel noise suppression based on the first microphone signal and the adjustable delayed second microphone signal.

4. The speech enhancement system of claim 1, further comprising:

a gain adjust to adjust a gain of the adjustable delayed second microphone signal for input to the noise suppressor; and

a gain estimator to set the gain of the gain adjust, to match a level of the adjustable delayed second microphone signal to a level of the first microphone signal when neither a distant talker nor a user is speaking.

5. The speech enhancement system of claim 1, further comprising:

a delay estimator to set the adjustable delay of the first delay buffer; and

a finger tap detector to enable the delay estimator.

6. The speech enhancement system of claim 1, further comprising:

a delay estimator to set the adjustable delay of the first delay buffer;

a first voice activity detector to detect voice activity on an accelerometer signal;

a second delay buffer to delay output of the first voice activity detector by a total delay;

a second voice activity detector to detect voice activity on the first microphone signal; and

the delay estimator to be triggered by a detection made by the second voice activity detector and not by the first voice activity detector, as delayed by the total delay through the second delay buffer.

7. The speech enhancement system of claim 1, further comprising:

a gain estimator to set a gain on the adjustable delayed second microphone signal;

a first voice activity detector to detect voice activity on an accelerometer signal;

a second delay buffer to delay output of the first voice activity detector by the adjustable delay;

a third voice activity detector to detect voice activity on the first microphone signal; and

the gain estimator to be triggered by a logical combination of the adjustable delayed output of the second delay buffer and output of the third voice activity detector.

8. The speech enhancement system of claim 1, wherein the wireless delay is a time interval between the remote microphone signal being produced in the remote device and being received in the headset housing after transmission over an RF communications link with the remote device.

9. The speech enhancement system of claim 1, wherein the acoustic delay is a time interval needed for sound, picked up in the remote microphone signal, to travel through an acoustic path from its sound source to the second microphone.

10. The speech enhancement system of claim 1, further comprising:

a headset housing in which the wireless receiver, the first delay buffer, the noise suppressor, and the earpiece speaker are integrated, wherein the remote device comprises a smart phone or other wireless device having the first microphone.

11. A method for speech enhancement in a listening system using a remote microphone, comprising:

receiving a first microphone signal from a first microphone in a remote device;

receiving into a first delay buffer a second microphone signal from a second microphone of a listening device;

delaying, through the first delay buffer, the second microphone signal by an adjustable delay, wherein the adjustable delay is based on a difference between a wireless delay and an acoustic delay; and

modifying the first microphone signal, the adjustable delayed second microphone signal, or both, through a noise suppressor to produce an output audio signal for driving an earpiece speaker of the listening device.

12. The method for speech enhancement of claim 11, further comprising:

in the noise suppressor, selecting the first microphone signal, a gain adjusted version of the adjustable delayed second microphone signal, or a combination of the first microphone signal and the gain adjusted version of the adjusted delayed second microphone signal, to produce the output audio signal.

13. The method for speech enhancement of claim 11, further comprising:

performing, in the noise suppressor, two channel noise suppression based on the first microphone signal and the adjustable delayed second microphone signal.

14. The method for speech enhancement of claim 11, further comprising:

setting a gain adjust to match a level of the adjustable delayed second microphone signal to a level of the first microphone signal when neither a distant talker nor a user of the listening device is speaking, for input to the noise suppressor.

15. The method for speech enhancement of claim 11, further comprising:

detecting a finger tap in the listening device; and

setting the adjustable delay of the first delay buffer, as enabled by the detected finger tap.

16. The method for speech enhancement of claim 11, further comprising:

triggering a process for setting the adjustable delay of the first delay buffer, based on i) detecting voice activity on the first microphone signal and ii) contemporaneously not detecting voice activity on an accelerometer signal delayed through a second delay buffer.

17. The method for speech enhancement of claim 11, further comprising:

triggering a gain estimator to set a gain on the adjustable delayed second microphone signal, based on a logical combination of a delayed output of detecting voice activity on an accelerometer signal and detecting voice activity on the first microphone signal.

18. The method for speech enhancement of claim 11, further comprising:

adjusting volume for the output audio signal.

19. The method for speech enhancement of claim 11, further comprising:

estimating the wireless delay; and

estimating the acoustic delay.

20. The method for speech enhancement of claim 11, wherein the listening device is a wireless headset in which the first delay buffer and the noise suppressor are integrated, the method further comprising:

driving the earpiece speaker of the wireless headset with the output audio signal.