On/off head detection of personal acoustic device using an earpiece microphone

• US 10,080,092 B2
• Filed: 10/31/2017
• Issued: 09/18/2018
• Est. Priority Date: 11/03/2016
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Shetye, Mihir D., Oommen, Binu K., McElhone, Dale
• Primary Examiner(s): Anwah, Olisa
• Application Number:
  US15/798,564
• Publication Number:
  US 20180124532A1
• Time in Patent Office: 322 Days
• CPC Class Codes: H04R 1/1041 Mechanical or electronic switches, or control elements switches in general H01H
• 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 1/1091 Details not provided for in groups H04R1/1008 - H04R1/1083
• 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 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10

Abstract

A method of controlling a personal acoustic device includes generating a first electrical signal responsive to an acoustic signal incident at a microphone disposed at a location on an earpiece of the personal acoustic device such that the microphone is acoustically coupled to an environment external to the earpiece. A characteristic of a transfer function based on the first electrical signal and a second electrical signal provided to a speaker in the earpiece is determined. An operating state of the personal acoustic device is determined form the characteristic of the transfer function. The operating state include a state in which the earpiece is positioned in the vicinity of an ear of a user and a second state in which the earpiece is absent from the vicinity of the ear of the user.

Claims

1. A method of controlling a personal acoustic device comprising:

generating a first electrical signal responsive to an acoustic signal incident at a microphone disposed at a location on an earpiece of the personal acoustic device such that the microphone is acoustically coupled to an environment external to the earpiece;

determining a characteristic of a transfer function based on the first electrical signal and a second electrical signal provided to a speaker in the earpiece; and

determining an operating state of the personal acoustic device based on the characteristic of the transfer function, the operating state comprising at least a first state in which the earpiece is positioned in the vicinity of an ear of a user and a second state in which the earpiece is absent from the vicinity of the ear.

2. The method of claim 1 wherein the characteristic of the transfer function is a magnitude of the transfer function at one or more predetermined frequencies.

3. The method of claim 1 wherein the characteristic of the transfer function is a power spectrum over a predefined frequency range.

4. The method of claim 1 wherein the characteristic of the transfer function is a phase of the transfer function at a predetermined frequency.

5. The method of claim 2 wherein the predetermined frequency is about 1.5 KHz.

6. The method of claim 1 wherein the second electrical signal comprises a tone.

7. The method of claim 6 wherein the tone is less than 20 Hz.

8. The method of claim 6 wherein the tone is in a frequency range from about 5 Hz to about 300 Hz.

9. The method of claim 6 wherein the tone is in a frequency range from about 300 Hz to about 1 KHz.

10. The method of claim 4 wherein the second electrical signal comprises a tone at about 1.5 KHz.

11. The method of claim 1 wherein the second electrical signal comprises an audio content signal.

12. The method of claim 1 further comprising generating the second electrical signal.

13. The method of claim 1 wherein the steps of generating the first electrical signal and determining the characteristic of the transfer function are performed for each earpiece in a pair of earpieces, and wherein the step of determining the operating state of the personal acoustic device further includes comparing the characteristic of the transfer functions of the earpieces.

14. The method of claim 1 further comprising initiating an operation of the personal acoustic device or a device in communication with the personal acoustic device when the determining of the operating state of the personal acoustic device indicates a change in the operating state.

15. The method of claim 14 wherein initiating the operation comprises at least one of:

changing a power state, changing an active noise reduction state and changing an audio output state of the personal acoustic device or a device in communication with the personal acoustic device.

16. The method of claim 1 wherein the earpiece is one of an in-ear headphone, an on-ear headphone or an around-ear headphone.

17. A personal acoustic device comprising:

an earpiece having a microphone and configured for attachment to a head of a user or an ear of the user, the microphone disposed at a location on the earpiece such that the microphone is acoustically coupled to an environment external to the earpiece, the microphone configured to generate a first electrical signal responsive to an acoustic signal incident at the microphone, the earpiece having a speaker configured to generate an audio signal in response to a second electrical signal; and

a control circuit in communication with the microphone to receive the first electrical signal and in communication with the speaker for providing the second electrical signal, the control circuit configured to;

determine a characteristic of a transfer function based on the first electrical signal and the second electrical signal; and

determine an operating state of the personal acoustic device based on the characteristic of the transfer function, the operating state comprising at least a first state in which the earpiece is positioned in the vicinity of the ear and a second state in which the earpiece absent from the vicinity of the ear.

18. The personal acoustic device of claim 17 wherein the control circuit comprises a digital signal processor.

19. The personal acoustic device of claim 17 further comprising a power source in communication with the control circuit and wherein the control circuit is further configured to change a power state of the personal acoustic device when the operating state of the earpiece is determined to have changed.

20. The personal acoustic device of claim 17 further comprising a device in communication with the control circuit and wherein the control circuit is configured to control an operation of the device in response to a determination that the operating state of the earpiece is determined to have changed.