Configuration of the surface determination parameters for dimensional measurements with/using helpful metric as visualisation tool

Abstract

X-ray computed tomography allows scanning the internal attenuation coefficient of a part. In X-ray domain, this coefficient highly depends on the materials. To perform a dimensional measurement from the volumetric data, a surface (i.e. point cloud) is required, on which a shape can be fitted, and measurements of volumes or surfaces, and even rugosity can be evaluated. To extract this point cloud from the volume, different configurable algorithms exist, using different criteria. This can have an impact on the extracted surface and thus on the dimensional measurement and its uncertainty. A parametric study of the influencing parameters of the XCT measuring chain has been performed, using CIVA RT/CT software to model the tomographic acquisition and Python programs to extract the surface. This allows to have a better understanding of the sensitivity of the influencing parameters in the dimensional uncertainty, and to make some recommendations for the surface determination