摘要
基于小波变换的门限去噪算法是去除数字信号中白噪声的有效算法。在实际应用中,这种非线性滤波方法有2个核心问题需要解决。一个是门限闽值的选取;另一个是信号分解层数的确定。该文通过数字仿真证明了确定合适的分解层数的重要性。分析了白噪声污染的有用信号的小波变换系数特点。提出了1种分解层数的自适应确定方法,并提出了1种基于3σ法则原理的各层小波空间中阈值的选取方法。仿真结果表明,该文方法具有较好的去噪效果,尤其适合于强噪声背景下弱信号的监测。该文方法明确提出了基于小波变换的门限去噪算法中分解层数和门限阈值2个重要参数的确定方法,增强了这种去噪算法在工程应用中的实用性。
Threshold de-noising method based on wavelet transform is an efficient method to reduce the white noise in the digital signal. There are two key problems that need to be solved in practice use of this non-linear filter method. One is the determination of the threshold; another is the determination of the decomposition order. The necessity of determining a proper decomposition order is proved through digital simulation. The characteristics of the wavelet coefficients of useful signal polluted by white noise are analyzed. A new method is proposed to determine the decomposition order adaptively, and then a novel method based on the 3σ rule is brought forward to determine the threshold of each order of wavelet space. Simulation results show that the method proposed in this paper has good performance. It is especially suitable for the detection of faint signal under strong noise background. The methods of determining the two important parameters are proposed explicitly in this paper, and this will improve the practicability of threshold de-noising method based on wavelet transform in project use.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2004年第2期118-122,共5页
Proceedings of the CSEE
