基于小波收缩的改进阈值脑电信号去噪方法研究  

Research on improved threshold EEG signal denoising method based on wavelet contraction

作　　者：楚瑞博 王剑[1,2] 张迁[1] 陈欢欢 CHU Ruibo;WANG Jian;ZHANG Qian;CHEN Huanhuan(School of Information Engineering and Automation,Kunming University of Science and Technology,Kunming 650504,China;Key Laboratory of Artificial Intelligence in Yunnan Province,Kunming University of Science and Technology,Kunming 650504,China)

机构地区：[1]昆明理工大学信息工程与自动化学院,云南昆明650504 [2]昆明理工大学云南省人工智能重点实验室,云南昆明650504

出　　处：《现代电子技术》2023年第11期76-80,共5页Modern Electronics Technique

基　　金：云南省重大科技专项计划资助项目(202102AA100021)。

摘　　要：脑电(EEG)信号是脑神经细胞的电生理活动在大脑皮层的反应,但采集到的脑电信号一般都含有大量噪声信号。为了有效去除噪声信号并保留有用信息,在经过研究分析后提出一种基于小波收缩的改进阈值去除脑电信号噪声的方法,改进的阈值可以随着分解层数的变化而变化,在实际中可灵活应用。首先利用小波变换对脑电信号进行分解,得到多层的高频系数和低频系数;然后根据分解层次的不同,对小波系数进行自适应的阈值处理;将缩放后的小波系数重构,得到去噪声后的脑电信号。以信噪比(SNR)、均方根误差(RMSE)作为去噪效果的定量指标,通过实验对比了改进阈值法和软硬阈值法以及自适应阈值法,实验结果表明基于小波收缩改进的阈值法去噪效果优于其他三种阈值法。Electroencephalographic(EEG)signals are the responses of electrophysiological activities of brain nerve cells in the cerebral cortex,but the acquired EEG signals generally contain a large amount of noisy signals.In order to effectively remove the noisy signal and retain the useful information,a wavelet contraction based method to remove the noise of EEG signal by improved threshold is proposed after research and analysis.The improved threshold can be changed with the change of the number of decomposition layers,which can be applied flexibly in practice.The wavelet transform is used to decompose the EEG signal to obtain the high⁃frequency coefficients and low⁃frequency coefficients of multiple layers,and then the adaptive threshold processing of the wavelet coefficients is performed according to the different decomposition levels.The contracted wavelet coefficients are reconstructed to obtain the de⁃noised EEG signal.The signal⁃to⁃noise ratio(SNR)and root mean square error(RMSE)are taken as quantitative indexes of the denoising effect,and the improved thresholding method was compared with the soft and hard thresholding method and the adaptive thresholding method in experiments.The experimental results show that the denoising effect of the improved thresholding method based on wavelet contraction is better than that of the other three thresholding methods.

关 键 词：小波阈值去噪 脑电信号去噪 小波收缩 阈值改进 脑电信号分解 去噪指标 

分 类 号：TN911.7-34[电子电信—通信与信息系统]