Investigation on the effects of X-ray CT system geometrical misalignments on dimensional measurement errors

X-ray CT measurements are affected by a multitude of influence factors, among which the correct estimation of the CT system geometry is of major importance. The presence of geometrical misalignment and/or the wrong estimation of system geometry, indeed, leads to artifacts and distortions in the measured volume, and to measurement errors when performing metrological tasks. That is why it is important to quantify the effects of geometrical misalignments or misestimation on CT measurement accuracy. In this work, the effects of detector misalignment are experimentally investigated on a metrology CT system. Physical misalignments were purposefully induced on a flat-panel detector for investigating the influence of a detector out of plane rotation on measurement results. The experimental results show the effects of the induced detector misalignment on center-to-center measurements, diameter and form measurements on a calibrated ball bar. The effects of the amplitude of the angular misalignment induced are also shown.