Prior-online iteration for image reconstruction with electrical capacitance tomography

Electrical capacitance tomography (ECT) has been developed for imaging dielectric material distributions. While iterative image reconstruction algorithms may produce high-quality images, they are regarded as being time-consuming and currently can only be used offline. This paper describes a new image reconstruction algorithm for ECT. First, a coefficient matrix is generated through an offline iteration process. The matrix is then used for online image reconstruction in the same way as a sensitivity map is used in the popular linear back-projection (LBP) algorithm. This new algorithm can produce similar quality images to the Landweber iteration algorithm, but at the same speed as the LBP. An optimal step-length has been incorporated into the new algorithm for improved convergence. The algorithm has been evaluated by both simulation and experiment.