A Hybrid Iterative Algorithm for Electrical Capacitance Tomography

Tomasz Dyakowski1,2, Marcin Rutkowski2, Dariusz Sakson2

1Department of Chemical Engineering, UMIST, U.K.

2Computer Engineering Department, Technical University of Lodz, Lodz, Poland

ABSTRACT

This paper presents a novel two-step procedure for solving an inverse problem for electrical capacitance tomography. In the first step the dielectric permittivity distribution is calculated in nodal points of a coarse grid. The number of these points is smaller than the number of capacitance measurements (e.g. 64 for 66 measurements). A Modified Kaczmarz’s method is applied to solve this over determined problem. In the second step the results from the first are approximated in the nodal points of a finer grid. These are applied as a first guess for solving the under-determined problem by applying the SIRT algorithm.

The main advantage of the proposed algorithm is the higher image quality obtained for a smaller number of iterations. The effect of dielectric permittivity values on the reconstruction errors is also discussed.

Keywords Electrical capacitance tomography, reconstruction algorithm