基于改进的小波阈值函数语音增强方法

Improved Speech Enhancement Method Based on Wavelet Threshold Function

传统的小波阈值去噪方法会造成有用语音信号的损失,信噪比改善情况不理想.通过分析小波去噪原理,提出了一种改进的小波阈值函数语音增强方法.该方法结合小波软、硬阈值函数去噪的优点,克服了硬阈值函数的不连续及软阈值函数存在偏差的缺点.该方法首先对清浊音信号进行判断,接着采用变化的阈值对清浊音信号的小波系数进行不同的阈值处理.仿真实验结果表明,改进的方法非常适用于强噪声背景下的语音增强,无论在保留含噪语音信号中的清音信息,还是在信噪比改善指标上均优于传统的软阈值法、谱减法和听觉感知小波变换法.

The traditional wavelet threshold denoising method can cause the loss of useful speech signal, and the improvement of signal to noise ratio is not ideal. By analyzing the principle of wavelet denoising, an improved speech enhancement method of wavelet threshold function is proposed. The method combining the advantages of wavelet denoising for soft and hard threshold function, which can overcome disadvantage of discontinuous and bias for hard threshold function and soft threshold function respectively. The method makes judgment for voiced signal in the first place, then uses changed threshold to the wavelet coefficients of voiced and unvoiced signal in processing. The simulation experimental results show that the improved method is very suitable for speech enhancement under strong noise background, no matter keeping the voiced speech information in the noise speech signal or improving signal-to-noise ratio index, the improved method is better than traditional soft threshold method, the spectrum subtraction and the wavelet transform of auditory sensation.