Implementation and Evaluation of Two Helical CTReconstruction Algorithms in CIVA

International audienceThe large majority of industrial CT systems reconstruct the 3D volume by using an acquisition on a circular trajectory.However, when inspecting long objects which are highly anisotropic, this scanning geometry creates severe artifacts in thereconstruction. For this reason, the use of an advanced CT scanning method like helical data acquisition is an ecient way toaddress this aspect known as the long-object problem. Recently, several analytically exact and quasi-exact inversion formulas forhelical cone-beam reconstruction have been proposed. Among them, we identified two algorithms of interest for our case. Thesealgorithms are exact and of filtered back-projection structure. In this work we implemented the filtered-backprojection (FBP) andbackprojection-filtration (BPF) algorithms of Zou and Pan (2004). For performance evaluation, we present a numerical comparisonof the two selected algorithms with the helical FDK algorithm using both complete (noiseless and noisy) and truncated datagenerated by CIVA (the simulation platform for non-destructive testing techniques developed at CEA)