Inverse Radon Method Based on Electrical Field Lines for Dual-Modality Electrical Tomography

Abstract

Usually, the sensitivity matrix-based algorithms are used for image reconstruction in electrical tomography. These algorithms assume that the inverse problem is like that in the well-established medical CT and find successful applications. In the medical CT, rather than using the matrix-based algorithms, the inverse Radon transform and its derivatives dominate. However, these inverse transforms have not been introduced to electrical tomography due to a lack of the link between the parallel projections and electrical distributions. This article presents a map from electrical field lines to parallel lines in the inverse Radon transform and a novel image reconstruction algorithm by using the transform for dual-modality electrical tomography. The transform is realized through mapping the coordinates in electric field to the assumed parallel projections. The points of intersections between electrical field lines from different exciting electrodes are mapped to those of parallel lines from the related projections in a typical inverse Radon transform. Unlike the medical CT, different excitation schemes are related to distinct equivalent projections, and iterative scanning is used to apply all available projected data. Simulated and experimental data are implemented to validate the feasibility and effectiveness of the proposed algorithm, and performance comparisons are made with three algorithms, such as Calderon’s method, iterative method based on electrical field lines, and typical Landweber method. The proposed method yields good quality images in the least time and dynamic flames are monitored. Dual-modality images of material distributions are obtained to capture the ignition and blowout of the flame evolution in a Bunsen burner.