A simulation-based study on the influence of beam hardening in X-ray computed tomography for dimensional metrology

作者：Lifton Joseph J^*; Malcolm Andrew A; McBride John W

来源：Journal of X-Ray Science and Technology, 2015, 23(1): 65-82.

DOI：10.3233/XST-140471

• Computed tomography
• beam hardening
• dimensional metrology
• X-ray spectrum estimation
• ISO50
• surface determination

X-ray computed tomography (CT) is a radiographic scanning technique for visualising cross-sectional images of an object non-destructively. From these cross-sectional images it is possible to evaluate internal dimensional features of a workpiece which may otherwise be inaccessible to tactile and optical instruments. Beam hardening is a physical process that degrades the quality of CT images and has previously been suggested to influence dimensional measurements. Using a validated simulation tool, the influence of spectrum pre-filtration and beam hardening correction are evaluated for internal and external dimensional measurements. Beam hardening is shown to influence internal and external dimensions in opposition, and to have a greater influence on outer dimensions compared to inner dimensions. The results suggest the combination of spectrum prefiltration and a local gradient-based surface determination method are able to greatly reduce the influence of beam hardening in X-ray CT for dimensional metrology.

• 出版日期2015