UNCERTAINTY QUANTIFICATION IN DIMENSIONAL MEASUREMENTS BY COMPUTED TOMOGRAPHY DUE TO UNCERTAINTY IN DATA ACQUISITION GEOMETRICAL PARAMETERS

摘要

X-ray computed tomography (CT) is an imaging technique that provides a slice-wise volumetric reconstruction of the imaged part. Dimensional measurements can be performed on the reconstructed volume, making CT an attractive solution for non-destructive dimensional quality control, for example, of complex parts with inner geometries. The scanned object is reconstructed into a three-dimensional attenuation image by applying a tomographic reconstruction algorithm to the acquired 2D projections; the Feldkamp-Davis-Kress (FDK) algorithm is commonly used for reconstruction in cone-beam CT systems. Surfaces are segmented from the reconstructed volume and features are measured by fitting of geometrical primitives (spheres, planes, cylinders, etc.).