A new method of performance verification for x-ray computed tomography measurements

作者：Leonard F^*; Brown S B; Withers P J; Mummery P M; McCarthy M B

来源：Measurement Science and Technology, 2014, 25(6): 065401.

DOI：10.1088/0957-0233/25/6/065401

• CT
• x-ray tomography
• dimensional metrology
• accuracy
• repeatability
• coordinate metrology
• coordinate measuring machine (CMM)

Through its ability to measure otherwise inaccessible internal structures, x-ray computed tomography (CT) has become a useful tool in the field of dimensional metrology. However, the lack of international standards for performance verification and the determination of metrological characteristics has so far prevented it from becoming a standardized measurement technology. This paper considers how a test object comprising a dismantleable tetrahedral assembly of four calibrated alumina spheres can be employed to assess the metrological performance of an industrial-type CT system. The measurement accuracy was characterized in terms of sphere size, separation and form errors. In all cases, sub-voxel accuracy was achieved, with errors as small as 1/10 of a voxel being obtained. Good measurement repeatability was demonstrated even upon dismantling and reconstructing the reference object. The tetrahedral test object offers a simple robust solution for the verification of metrological performance with great versatility and adaptability.

• 出版日期2014-6