Voice detection apparatus

Abstract

A voice detection apparatus comprises a signal power calculation part (11) for calculating a signal power of an input voice signal for each frame of the input voice signal, a zero crossing counting part (12) for counting a number of polarity inversions of the input voice signal for each frame of the input voice signal, an adaptive prediction filter part (14) for obtaining a prediction error signal of the input voice signal based on the input voice signal, an error signal power calculation part (15) for calculating a signal power of the prediction error signal which is received from the adaptive prediction filter part, a power comparing part (16) for comparing the signal powers of the input voice signal and the prediction error signal and for obtaining a power ratio between the two signal powers, and a discriminating part (13) for discriminating voiced and silent intervals of the input voice signal based on the signal power calculated in the signal power calculation part, the number of polarity inversions counted in the zero crossing counting part and the power ratio obtained in the power comparing part. The discriminating part discriminates the voiced and silent intervals of the input voice signal based on the number of polarity inversions. On the other hand, the discriminating part compares an absolute value of a difference of power ratios between frames with a first threshold value and discriminates whether a present frame is a voiced interval or a silent interval depending on whether a previous frame is a voiced interval or a silent interval when the signal power of the input voice signal is less than a second threshold value.