Research On The Algorithm Of Vector Electromagnetic Computed Tomography

With the rapid development of online detection technology, EMT has gained great achievements by domestic and international research. Due to the EMT system is a real-time measurement which has some traits of non-touching, non-intrusive and non-destructive, EMT is widely used in the industrial process monitoring, geological exploration and other fields, which has tremendous value. However, due to the size of motivate/detecting coil and the nonlinear of magnetic field that coil collects, the sensitivity and spatial resolution of the existing EMT technology is relatively limited, which make EMT technology restricted in the detection of foreign object and human imaging area.In this dissertation, a new algorithm of vector electromagnetic tomography was formulated, which established a solid theoretical foundation for study EMT technology based on linear amorphous material. The vector electromagnetic tomography technology in this dissertation was used to rebuild three-dimensional magnetic field. Since this magnetic field is a vector, the dissertation divided it into a Z-direction component and a X-Y plane component to rebuild them respectively. Z-direction component is a scalar, the dissertation used wire cutting Z-direction magnetic field, generated the induced voltage as projection data, reconstructed Z-direction scalar field by filtered back-projection algorithm. X-Y plane component is a vector, the dissertation designed a two-dimensional vector field tomography algorithm based on the Helmholtz theorem, decomposing the tested vector field into solenoidal and irrotational components by Helmholtz theorem. Taking advantage of a sufficient number of vector projection data, the dissertation studied the algorithm of the reconstruction about the solenoidal component and achieved partial reconstruction of the vector field. Besides, the dissertation simulated the algorithm to rebuild the three-dimensional magnetic field which is generated by a finite steady current solenoid. The simulation realized the reconstruction of the Z-direction component and the solenoidal component of the X-Y plane component.