Optical tomography system using switch mode fan beam projection: modeling techniques

Abstract

This research concentrates on the implementation of 16 pairs of optical sensors in a process tomography system. The working principle is based on the switch and measure principle in electrical capacitance tomography (ECT), but uses fan beam shaped projection from light emitters. The fast settling time of optical sensors and wide coverage of an optical beam forms the interest to be implemented in a tomography system. At the initial stage, modeling has been carried out to predict the output from 16 pairs of optical sensors implemented with the switching principle. The 16 pairs of optical sensors consist of 16 3-mm PIN photo-diodes and 16 3-mm LEDs. The idea is applied with the assumption that the emission angle of the source is large enough to illuminate all the receivers and the emission power is uniform along the projection. The linear back projection algorithm is used to predict the result from the modeling. The results for concentration profiles and reconstructed images of the original objects show significant agreement for further research.