自适应小波阈值语音增强新方法

针对单一小波闻值语音增强方法降低语音可懂度这一问题，提出一种基于自适应小波闻值的语音增强新方法．根据噪声帧频谱的平整度判断出噪声的类型，即是白噪声（合频响曲线比较平整的有色噪声）还是频响曲线不平整的有色噪声．由于不同类型的噪声具有不同性质的Lipschitz指数，对两种不同的噪声类型分别采用不同的自适应小波阚值对带噪语音信号进行增强处理．用计算机仿真和实际环境录制的语音数据对该方法的性能进行了测试，实验结果表明在两种实验数据情况下，该方法均具有较好的噪声抑制能力．

A new approach for adaptive wavelet threshold speech enhancement

To solve the problem of poor understandability of the speech signals processed by the fixed wavelet threshold,a new speech enhancement method of adaptive wavelet thresholds is presented.The types of additive noise are to be ascertained firstly according to the differences in the spectrum amplitude between white noise(including color noise with flatting spectrum amplitude) and color noise with varying spectrum amplitude.Since Lipschitz exponent varies with the types of noise and speech,different kinds of the adaptive threshold function of the wavelet transform are used to enhance the noisy speech signals according to the types of noise.The proposed scheme was evaluated on noisy speech signals simulated by computer and recorded in real environment separately.Experimental results show the effectiveness of the proposed method.