Wearable audio device with head on/off state detection

• US 10,462,551 B1
• Filed: 12/06/2018
• Issued: 10/29/2019
• Est. Priority Date: 12/06/2018
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Kemmerer, Jeremy, Barnes, Christopher A.
• Primary Examiner(s): Sniezek, Andrew L
• Application Number:
  US16/212,040
• Time in Patent Office: 327 Days
• CPC Class Codes: G06F 3/165 Management of the audio stream, e.g. setting of volume, audio stream path
• 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 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 2460/01 Hearing devices using active noise cancellation
• CPC Class Codes: H04R 2460/03 Aspects of the reduction of energy consumption in hearing devices
• CPC Class Codes: H04R 29/001 for loudspeakers H04R29/007 takes precedence
• CPC Class Codes: H04R 5/02 Spatial or constructional arrangements of loudspeakers

Abstract

Various implementations include wearable audio devices and related methods for controlling such devices. Some approaches include: detecting a change from an on-head state to an off-head state with a first sensor system; calibrating a second, distinct sensor system after detecting the change from the on-head state to the off-head state; detecting a change from the off-head state to the on-head state using the calibrated second sensor system; and adjusting an operating state of at least one function of the wearable audio device in response to detecting the change from the on-head state to the off-head state or detecting the change from the off-head state to the on-head state.

Claims

1. A wearable audio device comprising:

an acoustic transducer for providing audio playback of an audio signal to a user;

an internal microphone acoustically coupled to an ear canal of a user, wherein the internal microphone generates an electrical signal responsive to an acoustic signal incident at the internal microphone;

a proximity sensor; and

a control circuit coupled with the acoustic transducer, the internal microphone and the proximity sensor, the control circuit configured to;

determine a magnitude of an acoustic transfer function based on the electrical signal and the audio signal at one or more predetermined frequencies to detect a change in the wearable audio device from an on-head state to an off-head state;

calibrate the proximity sensor after detecting the change from the on-head state to the off-head state;

detect a change in the wearable audio device from the off-head state to the on-head state using the calibrated proximity sensor; and

adjust at least one function of the wearable audio device in response to detecting the change from the on-head state to the off-head state or detecting the change from the off-head state to the on-head state.

2. The wearable audio device of claim 1, wherein the control circuit is configured to determine the magnitude of the acoustic transfer function during the audio playback to the user.

3. The wearable audio device of claim 1, further comprising an external microphone acoustically coupled to an environment external to the wearable audio device, wherein the external microphone generates an electrical signal responsive to an acoustic signal incident at the external microphone.

4. The wearable audio device of claim 1, wherein the control circuit is further configured to:

measure a first transfer function based upon the audio signal played back at the transducer and a control signal sent to the transducer for initiating the audio playback;

measure a second transfer function based upon the audio signal played back at the transducer and the electrical signal generated by the internal microphone; and

based on a comparison between the first transfer function and the second transfer function, detect a change in the wearable audio device from an on-head state to an off-head state.

5. The wearable audio device of claim 4, wherein the control circuit is configured to measure the first transfer function and the second transfer function for each of a left side of the wearable audio device and a right side of the wearable audio device, wherein the change from the on-head state to the off-head state is detected only when both the left side and the right side transfer functions are in agreement.

6. The wearable audio device of claim 1, wherein the proximity sensor comprises a capacitive proximity sensor or an infra-red (IR) sensor, and wherein the proximity sensor detects proximity to a head of the user to indicate the change from the off-head state to the on-head state.

7. The wearable audio device of claim 1, wherein the acoustic transducer is configured to continuously provide the audio playback while the wearable audio device is in the on-head state, wherein the audio playback comprises at least one of:

an audible feed or an interrogation signal.

8. The wearable audio device of claim 1, wherein the control circuit is further configured to pause the audio playback in response to detecting the change from the on-head state to the off-head state.

9. The wearable audio device of claim 1, wherein the predetermined frequencies are below 400 Hz.

10. The wearable audio device of claim 1, wherein the control circuit is further configured to:

resume the audio playback in response to the calibrated proximity sensor detecting the change from the off-head state to the on-head state; and

re-calibrate the proximity sensor to the off-head state each time the change from the on-head state to the off-head state is detected.

11. The wearable audio device of claim 1, wherein the control circuit comprises an active noise reduction (ANR) circuit for generating a feedback noise cancellation signal based on the electrical signal for output by the acoustic transducer.

12. The wearable audio device of claim 1, wherein the at least one function comprises an audio playback function, a power function, a capacitive touch interface function, an active noise reduction (ANR) function, a controllable noise cancellation (CNC) function or a shutdown timer function.

13. The wearable audio device of claim 1, further comprising a sensor system coupled with the control circuit for continuously operating during the on-head state, wherein the control circuit is further configured to:

receive an indicator of an off-head detection event from the sensor system; and

only in response to receiving the indicator of the off-head detection event, confirm the off-head detection event by using the control circuit to determine a magnitude of an acoustic transfer function based on the electrical signal and the audio signal at one or more predetermined frequencies to detect a change from the on-head state to the off-head state.

14. The wearable audio device of claim 1, further comprising a sensor system coupled with the control circuit, wherein the control circuit is further configured to:

detect the change in the wearable audio device from the on-head state to the off-head state from the determined magnitude of the acoustic transfer function; and

confirm the off-head state using the sensor system.

15. A computer-implemented method of detecting a state of a wearable audio device on a user, the method comprising:

detecting a change from an on-head state to an off-head state with a first sensor system, wherein the first sensor system comprises an internal microphone acoustically coupled to an ear canal of a user, wherein the internal microphone generates an electrical signal responsive to an acoustical signal incident at the internal microphone, the detecting of the change from the on-head state to the off-head state comprising determining a magnitude of an acoustic transfer function based on the electrical signal and the acoustical signal at one or more predetermined frequencies;

calibrating a second, distinct sensor system after detecting the change from the on-head state to the off-head state;

detecting a change from the off-head state to the on-head state using the calibrated second sensor system, wherein the second sensor system comprises a proximity sensor; and

adjusting an operating state of at least one function of the wearable audio device in response to detecting the change from the on-head state to the off-head state or detecting the change from the off-head state to the on-head state.

16. The computer-implemented method of claim 15, further comprising, using an active noise reduction (ANR) circuit to generate a feedback noise cancellation signal based on the electrical signal, for output by an acoustic transducer.

17. The computer-implemented method of claim 15, further comprising:

receiving an indicator of an off-head detection event from an additional sensor system; and

initiating the first sensor system to detect a change from the on-head state to the off-head state in response to the indicator of the off-head detection event from the additional sensor system.

18. The computer-implemented method of claim 15, further comprising:

continuously providing audio playback to the user while the wearable audio device is in the on-head state, wherein the audio playback comprises an audible feed or an interrogation signal detectable by the first sensor system; and

pausing the audio playback in response to the first sensor system detecting the change from the on-head state to the off-head state.

19. The computer-implemented method of claim 15, further comprising:

resuming the audio playback in response to the calibrated second sensor system detecting the change from the off-head state to the on-head state; and

re-calibrating the second sensor system to the off-head state each time the change from the on-head state to the off-head state is detected.

20. The computer-implemented method of claim 15, wherein the wearable audio device further comprises an external microphone acoustically coupled to an environment external to the wearable audio device, wherein the external microphone generates an electrical signal responsive to an acoustic signal incident at the external microphone.

21. The computer-implemented method of claim 20, further comprising:

measure a first transfer function based upon the audio signal played back at the transducer and a control signal sent to the transducer for initiating the audio playback;

measure a second transfer function based upon the audio signal played back at the transducer and the electrical signal generated by the internal microphone; and

based on a comparison between the first transfer function and the second transfer function, detecting a change in the wearable audio device from an on-head state to an off-head state.

22. The computer-implemented method of claim 21, further comprising measuring the first transfer function and the second transfer function for each of a left side of the wearable audio device and a right side of the wearable audio device, wherein the change from the on-head state to the off-head state is detected only when both the left side and the right side transfer functions are in agreement.

23. A wearable audio device comprising:

an acoustic transducer for providing audio playback of an acoustical signal to a user;

an internal microphone acoustically coupled to an ear canal of a user, wherein the internal microphone generates an electrical signal responsive to an acoustic signal incident at the internal microphone; and

a control circuit coupled with the acoustic transducer and the internal microphone, the control circuit configured to;

determine a magnitude of an acoustic transfer function based on the electrical signal and the acoustical signal at one or more predetermined frequencies to detect a change in the wearable audio device from an on-head state to an off-head state;

pause the audio signal when the change from the on-head state to the off-head state is detected;

output an interrogation signal or narrowband noise at the acoustic transducer while the audio signal is paused;

determine a magnitude of an acoustic transfer function based on the electrical signal and the interrogation signal or narrowband noise at one or more predetermined frequencies to detect a change in the wearable audio device from the off-head state to an on-head state; and

adjust at least one function of the wearable audio device in response to detecting the change from the on-head state to the off-head state or detecting the change from the off-head state to the on-head state.