Magnetotelluric Data Processing Based On Local Mean Decomposition And Wavelet Threshold Denoising

Magnetotelluric sounding method is using the principle of electromagnetic induction to detect the distribution features of the underground rock and mineral,however, in the process of long-term practical electromagnetic exploration discovery,wild earth electromagnetic signal usually being affected by many kinds of noises,seriously affect the reliability of the distribution structure of the electrical explanation.In view of the complex noise ore concentration area,this paper combined the adaptability of the local mean decomposition and the multi-resolution of wavelet analysis,and propose the method that based on local mean decomposition of wavelet threshold earth electromagnetic noise suppression.First of all, get some noise signal local mean decomposition factorial(Production Functiion, PF)component function;then, based on all orders of component selection and analysis,select the processed PF component and select the appropriate wavelet threshold denoising to processing;at last, reconstruct the magnetotelluric useful signal.Simulate the noise of the measured data of typical model simulation through the computer,using the proposed algorithm in this paper,select different wavelet functions, the number of decomposition layers, and threshold value method to deal with the noise of its respectively,results show that different threshold will get different denoising effect,and keep the high frequency(PF1) component information cases will get better denoising effect.Then applied the method to the ore concentration area measured magnetotelluric data,to further verify the feasibility of thismethod,the experimental results show that,the method proposed in this paper can extract the contour characteristics of large scale interference,apparent resistivity and phase curves have obviously improved in low frequency band,deposits in the proximal interference has been effectively suppressed. The proposed method provides a new solution for the future research of magnetotelluric sounding in the areas in strong cultural interference areas, and it will have a good application value.