Optical Fibres For Process Tomography: A Design Study

S.Ibrahim1, R.G.Green2, K.Dutton3, R. Abdul Rahim4, K.Evans5 & A.Goude6

1 & 4. Faculty of Electrical Engineering, Universiti Teknologi Malaysia. s.ibrahim@shu.ac.uk
2,3,5 & 6. School of Engineering, Sheffield Hallam University, Sheffield, S1 1WB. r.g.green@shu.ac.uk, ruzairi@suria.fke.utm.my

Abstract - This paper describes modelling of optical fibre sensing arrays aimed at optimising the design of the tomography system being built by the authors. Two forms of optical sensing are considered; one relating to optical attenuation due to material with differing optical densities, the second to ?optical path length?, which is used for opaque solids in air or liquid. The circular flow pipe is mapped onto an eight by eight rectangular array of pixels. Four flow models are investigated: a single pixel flow, two pixels flow, half flow and full flow models. Different arrangements of the fibre sensors are considered for various projections. The forward problem is solved for all combinations of flow model and sensor arrangement. Back projection and filtered back projection are used to reconstruct the image. A modified reconstruction algorithm combining LBP and a priori knowledge is outlined. Numerical tests, based on the reconstruction, are used to identify the best system to be implemented in hardware.

Keywords: Optical Fibres, Process Tomography, Models