3-D-Scantrajektorien für die dimensionelle Röntgen-Computertomographie durch adaptive Messobjektneigung

Description

In this thesis, the scan trajectory for dimensional Computed Tomography was extended through adaptive component tilting during the scan. For this purpose, a hexapod was used as additional positioning unit in a commercial CT device. By correctly considering the kinematic chain for CT reconstruction and suitable trajectory determination, 3D scan trajectories could successfully be applied without loss of measurement accuracy, despite the additionally introduced positioning errors. The methodology from literature regarding trajectory calibration has been extended, among other things, through a cost-efficient method using only a single sphere, which however comes with a high sensitivity to systematic positioning errors. The potential for avoiding cone beam artefacts and reducing imaging artefacts by avoiding high absorption in regions of interest has been successfully demonstrated. For trajectory planning, two different approaches were examined. The comprehensive sampling of the maximum possible trajectory range through the fusion of circular trajectories without further action did not yield substantial improvements. On the other hand, the use of a quality measure specifically developed for surface-based metrology led to a significant reduction of measurement errors, especially for a small number of projections.