一种新阈值函数的小波包语音增强算法

针对传统软、硬阈值函数去噪方法增强的语音存在失真的问题,提出一种新阈值函数的小波包语音增强算法,同时给出了新阈值函数和新的Bark尺度小波包分解结构。新阈值函数在小波包系数绝对值大于给定阈值的区间内,灵活地结合了软、硬阈值函数;在小波包系数绝对值小于给定阈值的区间内,用一种非线性函数代替传统阈值函数中的简单置零,实现了阈值函数的平缓过渡;新的60个频带Bark尺度小波包分解结构能更好地模拟人耳的听觉感知特性。仿真实验结果表明,在高斯白噪声和有色噪声背景下,与传统软、硬阈值函数去噪方法相比,新算法有效提高了增强语音信噪比和分段信噪比,减少了语音失真,具有更好的去噪效果。

New threshold function of wavelet packet speech enhancement algorithm

Aiming at enhanced speech by using the traditional soft and hard threshold functions methods had the problem of distortion, this paper proposed a new threshold function of wavelet packet speech enhancement algorithm, and put forward the new threshold function and the new Bark scale wavelet packet decomposition structure. The new threshold function flexibly combined the soft and hard threshold functions when wavelet packet coefficients were greater than the given threshold. When wavelet packet coefficients were less than the given threshold, it used a nonlinear function to instead of setting wavelet packet coefficients to zero simply in the traditional threshold function, and it achieved the smooth transition of the threshold function. The new 60 sub-bands Bark scale wavelet packet decomposition structure could achieve better simulation of the human ear auditory perception characteristics. Simulation experimental results show that comparing with traditional threshold function methods, the new proposed algorithm improves the SNR and SSNR of the enhanced speech significantly and reduces the speech distortion in white Gaussian noise and colored noise background, and has better denoising effect.