SPEECH PROCESSING METHOD FOR SPEECH ENHANCEMENT IN HIGHLY NONSTATIONARY NOISE ENVIRONMENTS

摘要

A voice processing method for improving sound quality in a highly non-stationary noise environment is provided to adaptively estimate noise by using a size SNR(Signal-to-Noise Ratio) and a determining rule for discriminating whether a current sub-band is close to a voice or noise. A uniform wavelet packet-converted signal is generated with respect to a single interval of a voice signal with noise. An upper relative ratio, a lower relative ratio and a distribution ratio are obtained from a frame of the converted signal. An identifier of a determining rule is calculated by using the three types of ratios. It is successively discriminated whether a sub-band of a frame includes only noise or both noise and a voice by comparing the calculated identifier of the determining rule and a threshold value, a size SNR indicating an amount of noise existing in the sub-band, and noise is estimated by using the size of coefficient of the uniform wavelet packet existing in the sub-band and the size SNR. The estimated noise is subtracted from the voice with a noise to obtain an improved voice signal.