Dual helical cone-beam CT for inspecting large object

Article type: Research Article

Authors: Zou, Xiaobing^; | Zeng, Li^; | Li, Zongjian^;

Affiliations: ICT Research Center, Key Laboratory of Optoelectronic Technology and System of the Education Ministry of China, Chongqing University, Chongqing 400044, China | College of Optoelectronic, Chongqing University, Chongqing 400044, China | College of Mathematics and Physics, Chongqing University, Chongqing 400044, China

Note: [] Corresponding author. Tel.: +86 23 86394828; Fax: +86 23 65103562; E-mail: drlizeng@hotmail.com

Abstract: In cone beam industrial computed tomography (ICT), it is often required to inspect the large object using flat detector. If traditional helical scanning is used, the field of view (FOV) is limited due to the size of flat detector. As an alternative, a dual helical cone-beam scanning is proposed in this paper. Before each helical scanning, x-ray source and flat detector are horizontally translated a given distance, and part of the object is covered by x-ray at each view angle. Then the object function is reconstructed by use of the improved helical FDK algorithm, which does not rebin projection data. Simulations validate that the images, which are reconstructed by proposed scanning mode and improved algorithm with small flat detector, are similar to those from the conventional helical scanning and FDK algorithm with large flat detector. The improved FDK algorithm is not sensitive to translation step. Furthermore, the proposed scanning mode can extend the radius of FOV up to at least 1.7 times.

Keywords: ICT, large object, dual helix, cone beam, improved FDK algorithm

DOI: 10.3233/XST-2009-0225

Journal: Journal of X-Ray Science and Technology, vol. 17, no. 3, pp. 233-251, 2009