Interval Simulated Annealing applied to Electrical Impedance Tomography image reconstruction with fast objective function evaluation

Abstract

The Electrical Impedance Tomography (EIT) reconstruction problem can be solved as an optimization problem in which the discrepancy between a simulated impedance domain and the observed one is minimized. This optimization problem can be solved by a combination of Simulated Annealing (SA) for optimization and the Finite Element Method (FEM) for simulating the impedance domain. A new objective function based on the total least squares error minimization is proposed. This objective function is ill-conditioned with dense meshes. Two possibilities to overcome ill-conditioning are considered: combination with another objective function (Euclidean distance) and inclusion of a regularization term. To speed up the algorithm, results from previous iterations are used to improve the present iteration convergence, and a preconditioner is proposed. This new reconstruction approach is evaluated with experimental data and compared with previous approaches.