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Abstract Magnetic induction tomography is an imaging technology, which is to obtain the conductivity distribution by detecting the data on the boundary of the imaging area based on the eddy current principle. Back-projection algorithm is usually used for image reconstruction in the tomography imaging; however the positioning accuracy is decreased due to the nonlinear magnetic field distribution in the imaging area. In this paper, the relationship between magnetic field distribution and the phase difference in the detection coils has been studied, and a back-projection algorithm fit for the magnetic induction tomography was designed, which based on the theory that the phase difference can be described as the projection of the conductivity distribution along the magnetic field lines. The back-projection path was determined by the magnetic field lines in the imaging area, which solved the inaccuracy location problem. The reconstruction results showed that the minimum position error was 1 mm within the 200 mm imaging area, this value has been increased by 2-26 mm compared with the straight back-projection algorithm, and the visual quality also has greatly improved, which provided an effective reconstruction algorithm for the magnetic induction tomography.
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