Impact of the reconstruction method on the point spread function in electrical tomography

Abstract

The point spread function, the response of an imaging system to a point object, allows a comparison of the performance of different imaging systems. In this work the influence of the reconstruction algorithm and the regularisation method on the point spread function distribution of an electrical capacitance tomography (ECT) system is investigated. The reconstruction methods under study are a non-iterative back-projection method and, as iterative nonlinear alternative, a regularised spatial permittivity reconstruction based on a least squares functional. The influence of the Laplace-type generalised Tikhonov and minimum mean variation regularisation approaches is addressed. The results give an indication of the spatial resolution and small inclusion detection capabilities of the reconstruction approaches. The influence of the nonlinearity of the problem on larger object response functions is discussed. © Springer-Verlag 2007.