Experimental Test Of A Novel Reconstruction Approach Based On Irregular Grid For High-Speed Gamma-Ray Tomography

V. Mosorov1, R. Maad2,3, S.Lewndowski1, G. A. Johansen2, D. Sankowski1

1.Computer Engineering Department, Technical University of Lodz, Poland.

E-mail: mosorow[slewand][dsan]@kis.p.lodz.pl

2.University of Bergen, Department of Physics and Technology, Allégaten 55, N-5007 Bergen, Norway.

E-mail: geir.johansen@ift.uib.no

3.Sogn og Fjordane College, Faculty of Engineering, N-6800 Førde, Norway.

E-mail: rachid.maad@hisf.no

ABSTRACT

The gamma-ray tomograph with 85 CdZnTe detectors and 5 fan-beam collimated radioisotope sources, 500 mCi 241Am built at the University of Bergen, is promising equipment for the monitoring and investigation of different industrial processes. To obtain the density distribution within measured volume from a set of independent measured values, the image reconstruction algorithm is needed. In a classical approach, an image is discretized and approximated by a grid of identical area elements (pixels). However, the boundaries of the rays do not match with the boundaries of the pixels what can increase a static reconstruction error. The second problem with the classical approach is the determination of the optimal number of pixels of the reconstructed image. In the proposed approach the pixel grid is irregular and determined by the boundaries of the rays. The aim of this paper is to test the performance of the proposed technique for real data and comparing analysis with the classical techniques. The preliminary results of reconstruction based on proposed method are presented.

Keywords gamma-ray tomography, image reconstruction, irregular grid.