A new threshold selection method for X-ray computed tomography for dimensional metrology

The article presents a new method of air and material separation for X-ray tomography for engineering applications. It consists of executing additional calibration measurements and determining certain correction for air-material threshold values on the greyscale of the volumetric file obtained as a result of a tomographic measurement. Usability and effectiveness of this method has been experimentally verified on five different tomographs for industrial application. The proposed method performs better than existing well-known, automated algorithm ISO50% when measuring the volume as well as linear dimensions of workpieces made of different materials. Experiments shown considerable improvements of measurements for the tested conditions.