Patent Document ID: 8938389
Application ID: 13139909
Patent Flag: 1

Claim One:
1. A voice activity detector comprising: frame extracting unit which extracts frames from an inputted sound signal; feature quantity calculating unit which calculates multiple feature quantities of each of the extracted frames; feature quantity integrating unit which calculates an integrated feature quantity as integration of the multiple feature quantities by weighting the multiple feature quantities; and judgment unit which judges whether each of the frames is an active voice frame or a non-active voice frame by comparing the integrated feature quantity with a threshold value, wherein: the frame extracting unit extracts frames from sample data as voice data in which whether each frame is an active voice frame or a non-active voice frame is already known, and the feature quantity calculating unit calculates the multiple feature quantities of each of the frames extracted from the sample data, and the feature quantity integrating unit calculates the integrated feature quantity of the multiple feature quantities, and the judgment unit judges whether each of the frames extracted from the sample data is an active voice frame or a non-active voice frame by comparing the integrated feature quantity with the threshold value, and the voice activity detector further comprises: false rejection feature quantity calculating unit which calculates feature quantity regarding false rejected frames, and false acceptance feature quantity calculating unit which calculates feature quantity regarding false accepted frames; and weight updating unit which updates weights used by the feature quantity integrating unit for the weighting of the multiple feature quantities so that the rate between the false rejection feature quantity calculating unit and the false acceptance feature quantity calculating unit approaches a prescribed value.