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Ultrasonic echo canceler-based technique to detect participant presence at a video conference endpoint

  • US 9,319,633 B1
  • Filed: 03/19/2015
  • Issued: 04/19/2016
  • Est. Priority Date: 03/19/2015
  • Status: Active Grant
First Claim
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1. A method comprising:

  • transmitting an ultrasonic signal into a spatial region;

    transducing ultrasonic sound, including an echo of the transmitted ultrasonic signal, received from the spatial region at a microphone into a received ultrasonic signal;

    transforming the ultrasonic signal and the received ultrasonic signal into respective time-frequency domains that cover respective ultrasound frequency ranges;

    computing an error signal, representative of an estimate of an echo-free received ultrasonic signal, based on the transformed ultrasonic signal and the transformed received ultrasonic signal;

    computing power estimates of the error signal over time; and

    detecting a change in people presence in the spatial region over time based on a change in the power estimates of the error signal over time.

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