L. Zeng, X. Zou, J. Wang, P. Wang (PRC), and P.R. Hunziker (Switzerland)
Image processing, tomographic reconstruction, cone beam, improved scanning, off-center FDK algorithm
In cone-beam industrial computed tomography (ICT), it is common that the diameter of the object is larger than the width of the detector. The conventional 3rd generation circular scan trajectory and FDK algorithm are limited in this case. In this paper, a new “2nd + 3rd ” generation scan mode and an off-center reconstruction algorithm are presented for solving this problem. This “2nd + 3rd ” generation scan mode shares similarities with the conventional 2nd generation cone-beam CT, but the source and the detector are only translated a few times horizontally, and the rotary graduation equals that of the 3rd generation cone-beam CT. The object is reconstructed by joining the pieces of the reconstruction area and using an off-center FDK algorithm that is an extension of the standard FDK algorithm. In simulation experiments, compared with the 2nd generation cone-beam CT, the number of samples of this new imaging mode is reduced by a factor of 34, redundant projections are reduced at least a hundredfold, and the projections do not need reordering. The results of simulations show that the images reconstructed by this method are of good quality.
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