关键词: 语音增强, 维纳滤波, 先验信噪比, 直接判决

Abstract: An improved speech enhancement algorithm is proposed，which is based on a priori SNR estimation Wiener filtering.Firstly，the initial noise power spectrum NPS is estimated by computing the statistical average of the silent segments.Next，the power spectrum of the speech segments is estimated and the noise power spectrum is updated by smoothing the initial noise power spectrum and the noisy speech power spectrum NSPS.Lastly，the abrupt increases in noise level are taken into account and the power spectrum of the noise is adjusted adaptively according to the rate of the NSPS to NPS.The verification experiment between the proposed algorithm and other speech enhancement algorithm which based on short-time spectral estimation is implemented.The experiment result shows that the residual noise is reduced significantly and the speech distortion，and then the speech intelligibility are increased.

Key words: speech enhancement, Wiener filtering, a priori Signal to Noise Ratio（SNR）, decision directed