Headphone off-ear detection
First Claim
1. A signal processor for headphone off-ear detection, the signal processor comprising:
- an audio output to transmit an audio signal toward a headphone speaker in a headphone cup;
a feedback (FB) microphone input to receive a FB signal from a FB microphone in the headphone cup; and
an off-ear detection (OED) signal processor configured to;
determine an audio frequency response of the FB signal over an OED frame as a received frequency response,determine an audio frequency response of the audio signal times an off-ear transfer function between the headphone speaker and the FB microphone as an ideal off-ear response,generate a difference metric comparing the received frequency response to the ideal off-ear frequency response, andemploy the difference metric to detect when the headphone cup is disengaged from an ear.
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Accused Products
Abstract
Disclosed is a signal processor for headphone off-ear detection. The signal processor includes an audio output to transmit an audio signal toward a headphone speaker in a headphone cup. The signal processor also includes a feedback (FB) microphone input to receive a FB signal from a FB microphone in the headphone cup. The signal processor also includes an off-ear detection (OED) signal processor to determine an audio frequency response of the FB signal over an OED frame as a received frequency response. The OED processor also determines an audio frequency response of the audio signal times an off-ear transfer function between the headphone speaker and the FB microphone as an ideal off-ear response. A difference metric si generated comparing the received frequency response to the ideal off-ear frequency response. The difference metric is employed to detect when the headphone cup is disengaged from an ear.
18 Citations
20 Claims
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1. A signal processor for headphone off-ear detection, the signal processor comprising:
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an audio output to transmit an audio signal toward a headphone speaker in a headphone cup; a feedback (FB) microphone input to receive a FB signal from a FB microphone in the headphone cup; and an off-ear detection (OED) signal processor configured to; determine an audio frequency response of the FB signal over an OED frame as a received frequency response, determine an audio frequency response of the audio signal times an off-ear transfer function between the headphone speaker and the FB microphone as an ideal off-ear response, generate a difference metric comparing the received frequency response to the ideal off-ear frequency response, and employ the difference metric to detect when the headphone cup is disengaged from an ear. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method comprising:
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employing a tone generator to generate an off-ear detection (OED) tone at a specified frequency bin; injecting the OED tone into an audio signal forwarded to a headphone speaker; detecting a noise floor from a feedforward (FF) microphone signal; adjusting a volume of the OED tone based on a volume of the noise floor; generating a difference metric by comparing a Feedback (FB) signal from a FB microphone to the audio signal; and employing the difference metric to detect when the headphone cup is disengaged from an ear. - View Dependent Claims (17, 18, 19, 20)
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Specification