Imagereconstruction approaches for Philips magnetic induction tomograph

Abstract

Magnetic induction tomography (MIT) is a technique for imaging internal conductivity distribution of an object. In MIT current-carrying coils are used to induce eddy currents in the object. The secondary magnetic field due to the eddy currents is sensed with other coils. From these measurements an image can be reconstructed. The image reconstruction is a nonlinear, three-dimensional, ill-posed inverse problem which necessitates a solution of the time harmonic Maxwell's equations as well as some regularization due to the ill-posedness. In this paper we introduce approaches for reconstructing MIT images developed for a Philips 16 channel MIT system. We consider low conductivity applications, conductivity less than 10 Sm-1, and we use frequency of 10 MHz. The Maxwell's equation in frequency domain for the electric field is solved with finite element method using edge elements and regularized inversion techniques are used in solving the inverse problem. Both difference and static image reconstruction approaches are considered. Results from simulations and real measurements collected with the Philips 16 channel MIT system are shown. © Springer-Verlag 2007.