| 摘要 |
On the basis of parameters representing background noise characteristics and parameters representing voice characteristics of a current frame, a voice activity detector 42 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 42 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.
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