US Patent:
20010034601, Oct 25, 2001
Inventors:
Kaoru Chujo - Sunnyvale CA, US
Toshiaki Nobumoto - Fukuoka, JP
Mitsuru Tsuboi - Kawasaki, JP
Naoji Fujino - Kawasaki, JP
Noboru Kobayashi - Kawasaki, JP
International Classification:
G10L015/20
Abstract:
On the basis of parameters representing background noise characteristics and parameters representing voice characteristics of a current frame, a voice activity detector identifies whether the current frame is a non-active voice segment of background noise only or an active voice segment in which background noise has been superimposed on voice. The voice activity detector updates the background-noise characteristic parameters in each frame, irrespective of whether requirements for updating the background-noise characteristic parameters have been satisfied, in an interval of time from start of a steady operation for detection of voice activity to identification of an active voice segment. Further, the voice activity detector relaxes the update requirements of the background-noise characteristic parameters based upon results of voice activity and voice non-activity detection and, when these requirements have been satisfied, updates the background-noise characteristic parameters. As a result, processing for updating the background-noise characteristics parameters will not stop, thereby allowing these parameters to reflect the latest background noise at all times. This makes it possible to identify an active voice segment and a non-active segment easily and precisely.