基于提升小波变换的心音去噪新方法

A new method of heart sound denoising based on lifting wavelet transform

针对传统的小波阈值函数去噪无法有效滤除信号中的特定噪声,结合软、硬阈值函数的优点,提出了一种基于提升小波新阈值函数算法对心音信号进行去噪.首先利用提升小波变换对心音信号进行分解;然后利用新阈值函数更新其小波系数进行重构;最后与提升小波软、硬阈值函数去噪后的心音进行了希尔伯特包络提取验证其去噪效果.实验结果表明,提出的提升小波去噪新方法较软、硬阈值方法有更好的滤波效果,且提取的曲线包络更加清晰、平滑.

Aiming at the traditional wavelet threshold function denoising, it can not effectively filter out the specific noise in the signal. Combining the advantages of soft and hard threshold functions, a new threshold function algorithm based on lifting wavelet is proposed to denoise the heart sound signal. Firstly, the heartbeat signal is decomposed by lifting wavelet transform;then the wavelet coefficients are updated by the new threshold function for reconstruction;finally, the Hilbert envelope extraction is performed to improve the denoising effect of the heart sounds after denoising the wavelet soft and hard threshold functions.The experimental results show that the proposed method for improving wavelet denoising has better filtering effect than the soft and hard threshold method, and the extracted curve envelope is more clear and smooth.