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Proceedings Paper

Image quality and accuracy in x-ray microtomography
Author(s): Graham R. Davis
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Paper Abstract

It is known that the reconstruction produced by the standard cone beam back-projection algorithm, with circular orbit, gives only an approximation to the true three dimensional x- ray attenuation map. It is generally thought that the errors are acceptable if the cone angle is not too large. Such assumptions are based, at least in part, on reconstructions of ellipsoids or spheres. However, this is not representative of most of the specimens used for microtomography which may give rise to larger errors. We have therefore designed a mathematical cone beam phantom generator, capable of calculating a projection data set from analytical specimens described by surface polygons. Using this phantom generator, we have tested a variety of different types of 'specimen' and have shown that when they have certain characteristics, serious errors can occur with very small cone angles, while others will tolerate much larger angles. For a more authentic simulation, a polygon surface was generated from a microtomography scan of a real piece of walrus tusk. This has been used to determine the susceptibility of this type of specimen to cone-beam related errors for various cone angles.

Paper Details

Date Published: 22 September 1999
PDF: 9 pages
Proc. SPIE 3772, Developments in X-Ray Tomography II, (22 September 1999); doi: 10.1117/12.363716
Show Author Affiliations
Graham R. Davis, Queen Mary and Westfield College (United Kingdom)

Published in SPIE Proceedings Vol. 3772:
Developments in X-Ray Tomography II
Ulrich Bonse, Editor(s)

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