| US 7,372,770 B2 | ||
| Ultrasonic Doppler sensor for speech-based user interface | ||
| Bhiksha Ramakrishnan, Watertown, Mass. (US); and Kaustubh Kalgaonkar, Atlanta, Ga. (US) | ||
| Assigned to Mitsubishi Electric Research Laboratories, Inc., Cambridge, Mass. (US) | ||
| Filed on Sep. 12, 2006, as Appl. No. 11/519,372. | ||
| Prior Publication US 2008/0071532 A1, Mar. 20, 2008 | ||
| Int. Cl. G01S 15/02 (2006.01) | ||
| U.S. Cl. 367—96 | 20 Claims |
| 1. A method for detecting speech activity, comprising:
directing an ultrasonic signal at a face of a speaker over time;
acquiring a Doppler signal of the ultrasonic signal after reflection by the face;
measuring an energy in the Doppler signal over time; and
comparing the energy over time to a predetermined threshold to detect speech activity of the speaker.
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