Electrical Impedance Tomography Based on Direct Search Method

Solution to impedance distribution in electrical impedance tomography (EIT) is an ill-posed nonlinear inverse problem. It is especially difficult to reconstruct an EIT image in the center area of a measured object. Tikhonov regularization with some prior information is a sound regularization method for static electrical impedance tomography under the condition that some true impedance distribution information is known a priori. This paper presents a direct search method (DSM) as pretreatment of image reconstruction through which one not only can construct a regularization matrix which may locate in areas of impedance change, but also can obtain an initial impedance distribution more similar to the true impedance distribution, as well as better current modes which can better distinguish the initial distribution and the true distribution. Simulation results indicate that, by using DSM, resolution in the center area of the measured object can be improved significantly.