Comparisons of three modelling methods for the forward problem in three-dimensional electrical capacitance tomography

Image reconstruction of electrical capacitance tomography (ECT) belongs to solving an inverse problem. The first step to solve the inverse problem is to establish a forward problem model which determines the capacitance values for known permittivity distribution. There are three main methods for ECT forward problem modelling. The first is based on the sensitivity definition. The second is based on the multiple linear regression (MLR) method. And the third is based on the electric field strength (EFS). In this study, comparisons of these three modelling methods for the forward problem in three-dimensional ECT are given in terms of modelling error, computational time and reconstruction quality. Comparison results show that the MLR method generates smallest modelling error and better reconstruction quality, especially for the very complex geometry with objects in the shape of letters H and U. However, the EFS method is significantly better than the other two methods in computational time.