Image reconstruction enhancement for electrical capacitance tomography using an improved sensitivity map

Abstract

Electrical Capacitance Tomography (ECT) is a viable application for measuring multi-phase flow. The quality of the reconstructed images is a significant factor for ECT practical application. ECT images are reconstructed by using the data from the sensitivity map to reconstruct an image of the region of interest. The resolution of the reconstructed image is strongly influenced by the sensitivity map computation. This paper focuses on the image reconstruction based on three types of sensitivity maps with changes made to the boundary condition on the finite element method software, specifically the boundary setting for the gap between the electrodes. The boundary settings are (1) ground (2) floating potential and (3) electrical insulator setting. A twelve-copper based ECT system is used to obtain the sensor measurement. From the modelling, the tendency of the electrical potential and electrical fields are presented. The sensitivity maps resulting from all boundary conditions tests are generated using MATLAB. Based on the image reconstructions, the boundary setting for gaps between electrodes of electrical floating potential and electrical insulator are able to produce image reconstruction of multiphase flow. Electrical insulator setting for the gap between electrodes is generally better than floating potential setting because, in addition to producing a reconstruction image of multiphase flow, it also eliminates high potential profiles at the edge of the electrodes.