Dynamic Electrical Impedance Tomography with Internal Electrodes

내부 전극을 이용한 동적 전기 임피던스 단층촬영법

  • Kang, Suk-In (Departmenht of Electrical & Electronic Engineering, Cheju National University) ;
  • Kim, Kyung-Youn (Departmenht of Electrical & Electronic Engineering, Cheju National University)
  • 강숙인 (제주대학교 전기전자공학부) ;
  • 김경연 (제주대학교 전기전자공학부)
  • Published : 2001.12.01

Abstract

Electrical impedance tomography(EIT) is a relatively new imaging modality in which the internal impedivity distribution is reconstructed based on the known sets of injected currents and measured voltages on the surface of the object. We describe a dynamic EIT imaging technique for the case where the resistivity distribution inside the object changes rapidly within the time taken to acquire a full set of independent measurement data. In doing so, the inverse problem is treated as the state estimation problem and the unknown state (resistivity) is estimated with the aid of extended Kalman filter in a minimum mean square error sense. In particular, additional electrodes are attached to the known internal structure of the object to enhance the reconstruction performance and modified Tikhonov regularization technique is employed to mitigate the ill-posedness of the inverse problem. Computer simulations are provided to illustrate the reconstruction performance of the proposed algorithm.

전기 임피던스 단층촬영법은 물체 표면의 전극을 통하여 전류를 주입하고 유기된 전압을 측정한 후, 물체 단면의 저항을 분포를 복원하는 기법이다. 본 논문에서는, 대상물체의 저항을 값의 분포가 급변하는 상황에 대한 동적 전기저항 단층활영법을 제안하였다. 특히, 복원 성능을 개선하기 위하여 물체 내부의 구조를 전극으로 사용하였으며, 비 선형 역문제를 상태 추정문제로 설정하여 확장 칼만필터를 이용하여 상태변수(저항율)를 추정하였다. 또한 역문제의 부정치성을 완화시키기 위하여 수정된 Tikhonov 조정기법을 비용함수에 도입하였다. 제안된 알고리즘의 성능을 분석하기 위해 컴퓨터 시뮬레이션을 수행했으며, 기존의 방법들에 비해 개선된 결과를 얻었다.

Keywords

References

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