Study Of Finite Element Method In Electromagnetic Tomography

Electromagnetic tomography(MIT)is a kind of electrical tomography(ET),MIT technology is similar to other ET technology operation method,and according to the impedance detection technology improvements to repair the capacitance tomography and resistance tomography Defects.MIT technology uses Faraday's law of electromagnetic induction,for magnetic materials,according to the characteristics of magnetic dipole,measured in different projection direction of the detection value,so as to reproduce the internal distribution of the object space,so that the measured sensitive field distribution to achieve visualization.MIT technology is divided into positive problem and inverse problem research,the main research content of this paper:1.Constructs the physical model of MIT technology,describes the working principle of the system,and deduces the mathematical model of electromagnetic induction imaging based on Maxwell's equations.2.Through analyzing and analyzing various methods of MIT mathematical model: linear approximation method,analysis method and finite element method,the finite element method is used to analyze the characteristics of MIT system.This paper summarizes the characteristics of different finite element method: the triangular element has a good shape,the algorithm is simple,the boundary of the unit is adaptable and flexible,and can be applied to various discrete irregular regions,and the rectangular unit is suitable for the discrete rectangular area,Compared to the accuracy of the unit is lower than the quadrilateral element.Therefore,according to the shape and calculation requirements of the MIT object space,the triangle part of the target field is divided into triangles and quadrilateral finite element method.The finite element analysis results and the sensitivity of the object space are given.3.The image reconstruction is carried out by the regularization method,the Landweber iterative method and the conjugate gradient algorithm.The image reconstruction is carried out by the iterative method,and the reconstructed image is evaluated by the image quality index.The conclusion is that the triangular-quadrilateral finite element The method of mapping conforms to the characteristics of MIT space,and the sensitivity chart conforms to the law of electromagnetic field.The iterative reconstruction algorithm based on finite element method reconstructs image quality.