On/off head detection of personal acoustic device

Patent metadata

Field	Value
Publication number	US-9860626-B2
Application number	US-201615157807-A
Country	US
Kind code	B2
Filing date	May 18, 2016
Priority date	May 18, 2016
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

A method of controlling a personal acoustic device includes performing a first analysis of one or more of an inner signal output by an inner microphone and an outer signal output by an outer microphone disposed on the personal acoustic device to determine if a buffet event has occurred. A second analysis is performed on or both of the inner and outer signals to determine if a voice event of a user occurred. If a buffet event is determined to have occurred and a voice event is determined not to have occurred, a third analysis is performed on the inner and outer signals to determine an operating state of the personal acoustic device. If a change in the operating state is determined, an operation of the personal acoustic device may be initiated such as changing a power state, an ANR state or an audio output state of the device.

First claim

What is claimed is:

1. A method of controlling a personal acoustic device comprising:
performing a first analyzing of an inner signal output by an inner microphone disposed within a cavity of a casing of an earpiece of a personal acoustic device and an outer signal output by an outer microphone disposed on the personal acoustic device so as to be acoustically coupled to an environment external to the casing of the earpiece to determine if a buffet event has occurred;
performing a second analyzing of at least one of: the inner signal and the outer signal to determine if a voice event of a user of the personal acoustic device has occurred;
in response to determining that a buffet event has occurred and that a voice event of a user of the personal acoustic device has not occurred, performing a third analyzing of the inner signal and the outer signal; and
determining an operating state of the personal acoustic device based on the third analyzing of the inner signal and the outer signal, the operating state comprising a first state in which the earpiece is positioned in the vicinity of an ear and a second state in which the earpiece is absent from the vicinity of the ear.

2. The method of claim 1 further comprising initiating an operation at 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.

3. The method of claim 2 , 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.

4. The method of claim 1 wherein performing the third analyzing comprises performing a classification analysis to determine the operating state of the earpiece.

5. The method of claim 4 wherein the classification analysis comprises a dimensionality reduction analysis.

6. The method of claim 5 wherein the dimensionality reduction analysis comprises one of a principal component analysis, a linear discriminant analysis, a neural network analysis, a Fisher discriminant analysis and a quadratic discriminant analysis.

7. The method of claim 1 wherein performing the third analyzing comprises calculating a ratio of a frequency response of the outer signal to the inner signal over a plurality of frequency ranges.

8. The method of claim 7 wherein performing the third analyzing further comprises multiplying each ratio of frequency responses by a predetermined weight to produce a plurality of weighted ratios and summing the weighted ratios to produce a state value indicative of the operating state of the personal acoustic device.

9. The method of claim 8 wherein performing the third analyzing further comprises comparing the state value to a first predetermined threshold to determine if the personal acoustic device is in the first state or the second state.

10. The method of claim 9 wherein performing the third analyzing further comprises comparing the state value to a second predetermined threshold to determine if the personal acoustic device is in a third state in which the personal acoustic device is worn by the user and the earpiece is absent from the vicinity of the ear.

11. The method of claim 1 wherein the operating state further comprises a third state in which the personal acoustic device is worn by the user and the earpiece is absent from the vicinity of the ear.

12. The method of claim 1 wherein the first analyzing comprises comparing at least one of: a power spectral density of the inner signal in a first frequency range and a power spectral density of the outer signal in the first frequency range to a predetermined threshold.

13. The method of claim 12 wherein the first frequency range comprises frequencies below approximately 10 Hz.

14. The method of claim 1 wherein the second analyzing comprises comparing at least one of: an energy level of the inner signal in a first frequency range and an energy level of the outer signal in the first frequency range to a predetermined threshold.

15. The method of claim 14 , wherein the first frequency range comprises frequencies ranging from approximately 150 Hz to approximately 1.5 KHz.

16. A personal acoustic device comprising:
an earpiece having a casing;
an inner microphone disposed within a cavity of the casing and outputting an inner signal representative of sound detected by the inner microphone;
an outer microphone disposed on the casing so as to be acoustically coupled to an environment external to the casing and outputting an outer signal representative of sound detected by the outer microphone; and
a control circuit in communication with the inner microphone to receive the inner signal and in communication with the outer microphone to receive the outer signal, the control circuit configured to:
perform a first analysis of the inner signal and the outer signal to determine if a buffet event has occurred;
perform a second analysis of at least one of: the inner signal and the outer signal to determine if a voice event of a user of the personal acoustic device has occurred; and
in response to determining that a buffet event has a occurred and that a voice event of a user of the personal acoustic device has not occurred, perform a third analysis of the inner signal and the outer signal to determine an operating state of the personal acoustic device, the operating state comprising a first state in which the earpiece is positioned in the vicinity of an ear and a second state in which the earpiece is absent from the vicinity of the ear.

17. The personal acoustic device of claim 16 wherein the control circuit comprises a digital signal processor.

18. The personal acoustic device of claim 16 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 determining of the operating state of the earpiece indicates a change in the operating state of the earpiece.

19. The personal acoustic device of claim 18 wherein the control circuit is configured to reduce a power supplied by the power supply in response to a determination that the operating state of the personal acoustic device is the second state.

20. The personal acoustic device of claim 18 wherein the control circuit is configured to increase a power supplied by the power supply in response to a determination that the operating state of the personal acoustic device has changed from the second state to the first state.

21. The personal acoustic device of claim 16 wherein the inner microphone is a feedback microphone in an acoustic noise reduction circuit.

22. The personal acoustic device of claim 16 wherein the outer microphone is a feedforward microphone in an acoustic noise reduction circuit.

23. The personal acoustic device of claim 16 wherein the control circuit is disposed in the casing of the earpiece.

24. The personal acoustic device of claim 16 further comprising a housing that is separate from the earpiece and wherein the control circuit is disposed in the housing.

25. The personal acoustic device of claim 16 wherein the control circuit is configured to change an acoustic noise reduction operation in response to a determination that the operating sta

Assignees

• Bose Corp

Inventors

• Ergezer Mehmet
• Cattell Joseph H
• Orescanin Marko

Classifications

• H04R2460/01

  Hearing devices using active noise cancellation · CPC title

• H04R1/1041 Primary

  Mechanical or electronic switches, or control elements (switches in general H01H) · CPC title

• H04R1/1083 Primary

  Reduction of ambient noise (active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06) · CPC title