一种均匀激励磁场磁感应成像的改进反投影算法

doi:10.3969/j.issn.0258-8021. 2014. 03.08

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Abstract This paper describes an improved backprojection algorithm of magnetic induction tomography with uniform magnetic excitation. According to BiotSavart law and the distribution of the sensitivity, a new algorithm with mixed weight was proposed to correct backprojection algorithm. Considering the sensitivity of zero point as the dividing point, this algorithm used different weighting coefficients which were separated by the dividing point. According to the simulation experiment of sensitivity distribution, when the distance r from detection coil to the meshing element of imaging area was 006 m, the sensitivity value was zreo, and the position of this meshing element was marked P₀. When the distance r from detection coil to meshing element was less than 0.06 m, the weighted coefficient was r²; otherwise, the weighting coefficients were the square of the distance r₀ from the detection coil to P₀ point. The experimental results of different positions of foreign body showed that the back projection algorithm with mixed weight well reflected the size of the target object. When the foreign object was located in the center and 0.015 m offcenter, the algorithm accurately reflected the position. However, when foreign object were 0.03 m off center, the location from the reconstructed image was more offcenter than that of the actual model. The experimental results of different size of foreign body revealed that the reconstructed image of smaller diameter of the foreign object could accurately reflect the size of the foreign object, while that of larger diameter could not. The improved back projection algorithm can eliminate a wide range of smearing image errors caused by the conventional backprojection algorithm to a certain extent, and can also locate the foreign object more accurately. Therefore, the proposed algorithm is of significance in the study of magnetic induction image.

Key words： magnetic induction tomography back projection algorithm Helmholtz coil

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	LIU Li¹LI Qian²HE Wei^2*XU Zheng²

Cite this article:

LIU Li¹LI Qian²HE Wei^2*XU Zheng². An Improved BackProjection Algorithm of Magnetic Induction Tomography with Uniform Magnetic Excitation[J]. journal1, 2014, 33(3): 313-319.

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http://cjbme.csbme.org/EN/10.3969/j.issn.0258-8021. 2014. 03.08 OR http://cjbme.csbme.org/EN/Y2014/V33/I3/313

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