基于频率域小波去噪的大地电磁信号工频干扰处理  

Suppression of Power Line Interference on MT Signals Based on the Frequency Domain Wavelet Method

作　　者：蔡剑华[1] 李晋[2] 

机构地区：[1]湖南文理学院信息研究所 [2]湖南师范大学物理与信息科学学院

出　　处：《地质与勘探》2015年第2期353-359,共7页Geology and Exploration

基　　金：国家自然科学基金项目(41304098;41404111);湖南省自然科学基金项目(12JJ4034);湖南省教育厅青年项目(13B076);湖南省重点建设学科-光学基金;湖南省重点实验室"光电信息集成与光学制造技术";"湖南省光电信息技术校企联合人才培养基地"共同资助

摘　　要：大地电磁测深(Magnetotelluric,MT)在油气勘查中得到越来越多的应用,针对MT中日益严重的工频干扰,从频率域着手,结合小波阈值去噪方法,提出了基于频率域小波去噪的MT信号工频干扰处理方法。先对受噪的MT信号进行傅里叶变换,得到其实部和虚部,再用小波阈值去噪的方法对实部序列和虚部序列分别进行去噪处理,最后将去噪后的实部和虚部联合,进行反傅里叶变换得到去噪后的信号。给出了去噪方法的原理、步骤,并用仿真信号和实测大地电磁信号验证了其有效性。结果表明:频率域小波阈值去噪的大地电磁信号工频干扰处理方法是正确、有效的,能有效且自适应地压制大地电磁信号中的工频干扰,突出被工频干扰淹没了的有用信号的信息。The magnetotelluric( MT) method is widely applied in oil and gas exploration. While power line interference is an increasingly serious problem with the development of society. In the frequency domain,combined with the wavelet threshold method,an approach to restrain power line interference is proposed for MT signal processing. Firstly,the Fourier transform is applied to the noised MT signal and its real and imaginary parts can be obtained. Then,wavelet threshold method is used to de-noise for the imaginary and the real part sequences. Finally,the de-noised real and the de-noised imaginary are assembled,and the anti-Fourier transform is conducted and the de-noised signal is obtained. The principle and steps of de-noising methods are presented. The simulated signals and the measured MT data are processed to verify its validity. The results show that the proposed method is correct and effective. It can suppress the power line interference on MT signal effectively and adaptively,and the useful information is highlighted which is concealed by the power line interference.

关 键 词：频率域 小波阈值 大地电磁信号 去噪 

分 类 号：P631.325[天文地球—地质矿产勘探]