ULTRASONIC ECHO CANCELER-BASED TECHNIQUE TO DETECT PARTICIPANT PRESENCE AT A VIDEO CONFERENCE ENDPOINT

A loudspeaker transmits an ultrasonic signal into a spatial region. A microphone transduces ultrasonic sound, including an echo of the transmitted ultrasonic signal, received from the spatial region into a received ultrasonic signal. A controller transforms the ultrasonic signal and the received ult...

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Bibliographische Detailangaben
Hauptverfasser:	BURENIUS, Lennart, BIRKENES, Oystein, TANGELAND, Kristian
Format:	Patent
Sprache:	eng ; fre ; ger
Schlagworte:	ANALOGOUS ARRANGEMENTS USING OTHER WAVES DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES ELECTRIC COMMUNICATION TECHNIQUE ELECTRICITY LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES MEASURING PHYSICS PICTORIAL COMMUNICATION, e.g. TELEVISION RADIO DIRECTION-FINDING RADIO NAVIGATION TESTING
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Beschreibung
Zusammenfassung:	A loudspeaker transmits an ultrasonic signal into a spatial region. A microphone transduces ultrasonic sound, including an echo of the transmitted ultrasonic signal, received from the spatial region into a received ultrasonic signal. A controller transforms the ultrasonic signal and the received ultrasonic signal into respective time-frequency domains that cover respective ultrasound frequency ranges. The controller computes 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. The controller computes power estimates of the error signal over time, and detects a change in people presence in the spatial region based on a change in the power estimates of the error signal over time.