Calculation of 3D Sensitivity Matrix for Electromagnetic Tomography System Using Boundary Elements and the Perturbative Approach

doi:10.1007/s12204-014-1503-9

Journal of shanghai Jiaotong University (Science) ›› 2014, Vol. 19 ›› Issue (3): 302-307.doi: 10.1007/s12204-014-1503-9

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Calculation of 3D Sensitivity Matrix for Electromagnetic Tomography System Using Boundary Elements and the Perturbative Approach

HE Min1 (何敏), ZHAO Qian2 (赵倩), YIN Wu-liang3* (尹武良)

(1. Department of Electrical Engineering, Shanghai Maritime University, Shanghai 201306, China; 2. School of Automation, Tianjin University, Tianjin 300072, China; 3. School of Electrical and Electronic Engineering, The University of Manchester, Manchester, M13 9PL, UK)
(1. Department of Electrical Engineering, Shanghai Maritime University, Shanghai 201306, China; 2. School of Automation, Tianjin University, Tianjin 300072, China; 3. School of Electrical and Electronic Engineering, The University of Manchester, Manchester, M13 9PL, UK)

Online:2014-06-30 Published:2014-07-15
Contact: YIN Wu-liang(尹武良) E-mail:wuliang.yin@manchester.ac.uk

Abstract

Abstract: Electromagnetic tomography (EMT) is a non-invasive imaging technique capable of mapping the conductivity and permeability of an object. In EMT, eddy currents are induced in the object by the activation coils, and the receiving coils can measure the EMT voltages. When the activation frequency is significantly large, we can treat the metallic targets as electrically perfect conductors (EPCs). In this situation, a thin skin approximation is reasonable and this type of scattering problem can be effectively treated by the boundary element method (BEM) formulated through integration equations. In this study, we compute three-dimensional (3D) sensitivity matrix between the sensors due to an EPC perturbation. Efficiency improvement is achieved through the utility of scalar magnetic potential. Two EPC objects, one sphere and one cube shaped, are simulated. The results agree well with the H dot H formula. Overall, we conclude that BEM can be used to calculate the 3D sensitivity matrix of an EMT system efficiently. This method is a general one for any shaped objects while the H dot H solution is only capable of producing the response for a small ball.

Key words: electromagnetic tomography (EMT)| electrically perfect conductor (EPC)| boundary element method (BEM)| sensitivity map

摘要： Electromagnetic tomography (EMT) is a non-invasive imaging technique capable of mapping the conductivity and permeability of an object. In EMT, eddy currents are induced in the object by the activation coils, and the receiving coils can measure the EMT voltages. When the activation frequency is significantly large, we can treat the metallic targets as electrically perfect conductors (EPCs). In this situation, a thin skin approximation is reasonable and this type of scattering problem can be effectively treated by the boundary element method (BEM) formulated through integration equations. In this study, we compute three-dimensional (3D) sensitivity matrix between the sensors due to an EPC perturbation. Efficiency improvement is achieved through the utility of scalar magnetic potential. Two EPC objects, one sphere and one cube shaped, are simulated. The results agree well with the H dot H formula. Overall, we conclude that BEM can be used to calculate the 3D sensitivity matrix of an EMT system efficiently. This method is a general one for any shaped objects while the H dot H solution is only capable of producing the response for a small ball.

关键词: electromagnetic tomography (EMT)| electrically perfect conductor (EPC)| boundary element method (BEM)| sensitivity map

CLC Number:

TP 202

HE Min1 (何敏), ZHAO Qian2 (赵倩), YIN Wu-liang3*(尹武良). Calculation of 3D Sensitivity Matrix for Electromagnetic Tomography System Using Boundary Elements and the Perturbative Approach[J]. Journal of shanghai Jiaotong University (Science), 2014, 19(3): 302-307.

References

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Calculation of 3D Sensitivity Matrix for Electromagnetic Tomography System Using Boundary Elements and the Perturbative Approach

Calculation of 3D Sensitivity Matrix for Electromagnetic Tomography System Using Boundary Elements and the Perturbative Approach

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