摘要
在水域电法勘探中,由于工频噪声及其谐波干扰导致无法达到满意的勘探效果,在信号强度较弱时,噪声信号甚至会淹没有效信号。面对工频噪声干扰严重的问题,结合工频噪声的特性,本文基于谐波滤波器及小波方法提出了一种抑制水域勘探过程中50 Hz交流电耦合噪声的电法测量数据处理方法。首先,基于窄带带通滤波器及高斯窗函数设计一款梳状滤波器,利用全通滤波器减去得到的梳状滤波器来获得中心频率可调的谐波滤波器,通过设置中心频率为50 Hz来抑制工频噪声及其谐波的干扰,通过对比测试选取最优高斯窗函数参数;然后,在小波去噪中,通过对比分析选取了Symlets小波基为小波变换的基函数;最后,基于LabVIEW设计了一个水域电法模拟勘探平台进行数据采集,用于验证所提出的方法。经过噪声实验分析,结果验证了谐波滤波器及小波去噪对工频干扰及其谐波分量的抑制效果,比较噪声信号和去噪信号,相对于原始信号,异常最大时的采集信号的信噪比从25.5149提高到了33.5871,而无异常情况下信噪比从23.7827提高到了30.3652,验证了该方法在水域电法勘探中的有效性,具有深入研究的价值。
In water area electrical exploration,due to power frequency noise and its harmonic interference,unsatisfactory exploration results often occur.When the signal strength is weak,the noise signal may even flood the effective signal.To solve this serious problem of power frequency noise interference,integrating the characteristics of power frequency noise,this paper proposes a data processing method of electrical measurement to suppress 50 Hz alternating current coupling noise in the process of water exploration,combining harmonic filter and wavelet method.Firstly,a comb filter is designed based on narrowband band-pass filter and Gaussian-window function.The comb filter obtained by subtracting the all pass filter is used to obtain a harmonic filter with adjustable design center frequency.The center frequency is set to 50 Hz to suppress the interference of 50 Hz power frequency noise and its harmonics,and the optimal Gaussian window function parameters are selected by comparative testing.Then,in wavelet denoising,the Symlets wavelet basis is selected as the basis function of wavelet transform through comparative analysis;and wavelet transform is used to improve the signal-to-noise ratio of the electrical signal of the measurement target.At the same time,a water area electrical simulation exploration platform is designed based on LabVIEW to collect data to verify the proposed method.Through noise experiment analysis,the results verify the suppression effect of harmonic filter and wavelet de-noising on power frequency interference and its harmonic components.Compared with the original signal,the signal-to-noise ratio of the collected signal with the maximum abnormality is increased from 25.5149 to 33.5871 when the noise signal and the denoised signal are compared,while the signal-to-noise ratio is increased from 23.7827 to 30.3652 when there is no abnormality,which verifies the effectiveness of this method in the electrical exploration of water areas.
作者
丁丹
吴双
昌彦君
吕淑娟
张伟
Ding Dan;Wu Shuang;Chang Yanjun;LüShujuan;Zhang Wei(321 Geological Team,Anhui Bureau of Geology and Mineral Resources,Tongling Anhui 244033,China;School of Geophysics and Geomatics,China University of Geosciences,Wuhan Hubei 430074,China;Division of Civil Engineering,Guizhou Vocational and Technical College of Water Resources and Hydropower,Qingzhen Guizhou 551416,China;Wuhan Geo-Detection and Technology Co.,Ltd.,Wuhan Hubei 430011,China)
出处
《工程地球物理学报》
2023年第6期817-824,共8页
Chinese Journal of Engineering Geophysics
基金
安徽省重点项目(编号:2020-Z-3-29)
贵州省水利科技项目(编号:KT202221)。
关键词
谐波滤波器
小波去噪
水域电法
harmonic filter
wavelet denoising
water area electrical method
