Ultrasonic Doppler Sensor for Voice Activity Detection

    •  Kalgaonkar, K., Hu, R., Raj, B., "Ultrasonic Doppler Sensor for Voice Activity Detection", IEEE Signal Processing Letters, Vol. 14, No. 10, pp. 754-757, October 2007.
      BibTeX TR2007-106 PDF
      • @article{Kalgaonkar2007oct,
      • author = {Kalgaonkar, K. and Hu, R. and Raj, B.},
      • title = {Ultrasonic Doppler Sensor for Voice Activity Detection},
      • journal = {IEEE Signal Processing Letters},
      • year = 2007,
      • volume = 14,
      • number = 10,
      • pages = {754--757},
      • month = oct,
      • issn = {1558-2361},
      • url = {}
      • }
  • Research Area:

    Speech & Audio

TR Image
Audio signal, spectrogram of Doppler signal, spectrogram of demodulated Doppler signal and energy track overlaid with VAD output for talker facing the mic/Doppler receiver.

This paper describes a robust voice activity detector using an ultrasonic Doppler sonar device. An ultrasonic beam is incident on the talker's face. Facial movements result in Doppler frequency shifts in the reflected signal, that are sensed by an ultrasonic sensor. Speech-related facial movements result in identifiable patterns in the spectrum of the received signal, that can be used to identify speech activity. These sensors are not affected by even high levels of ambient audio noise. Unlike most other non-acoustic sensors, the device need not be taped to a talker. A simple yet robust method of extracting the voice activity information from the ultrasonic Doppler signal is developed and presented in this paper. The algorithm is seen to be very effective and robust to noise, and can be implemented in real time.


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