关键词: 工业CT, 成像系统, 旋转中心, 正弦图, 对称投影, 无损检测

Abstract: For setting up an industrial computed tomography （ICT） imaging system, the determination of the center of the rotation （COR） of the rotating table is of critical importance as errors of the COR can lead to artifacts in CT images. In this article, the current methods for COR determination are described and their disadvantages are analyzed. Based on the analysis, a novel method is put forward. The proposed algorithm is based on the symmetry projection information implied in the sinogram and the following law: in relation to the two symmetrical projection views, the transmission path of the X-ray which passes through the COR of the rotating table is the same. Compared with the current methods, the proposed algorithm is applicable for the situation in which the tie line of the X-ray source and the COR is not strictly perpendicular to the detector. It does not need any phantom or geometry parameters, and is hardly affected by random noise. The feasibility of the method is validated by the experiment data.

Key words: industrial computed tomography, imaging systems, center of rotation, sinogram, symmetrical projection, nondestructive detection