Computed Tomography (CT) is a promising technology for both geometrical measurements and form measurements. However, a number of influence factors such as magnification, threshold determination strategies, and position of feature in the CT volume, have effect on the CT measurement performance. The present investigation concerns the measurement of flatness at different positions in the CT measurement volume using a milled miniature step gauge. The artifact is a 42 mm long step gauge with 11 grooves at 2 mm steps, made of polyphenylene sulphide PPS (? = 1.650 g/cmsup3/sup), with limited form error and good surface finish. A total of 132 flatness measurements were performed on the left step gauge grooves. The linear distribution of the grooves pointed out a non-uniform CT performance over the step gauge length with max deviation up to 25 μm. However, an appropriate choice of parameters yielded a reduction of the max deviation along the step gauge length by approximately 13 μm.
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机译：计算机断层扫描（CT）是一种用于几何测量和形状测量的有前途的技术。但是，诸如放大率，阈值确定策略以及特征在CT体积中的位置等许多影响因素都会影响CT测量性能。本研究涉及使用铣削微型阶梯规在CT测量体积中不同位置进行平面度测量。该工件是一个42毫米长的台阶仪，具有11个2毫米台阶的凹槽，由聚苯硫醚PPS（？= 1.650 g / cm 3 ）制成，具有有限的形状误差和良好的表面光洁度。在左踏板规槽上总共进行了132次平整度测量。凹槽的线性分布指出了在阶梯规长度上的CT性能不均匀，最大偏差高达25μm。但是，适当选择参数会导致沿步距长度方向的最大偏差减小约13μm。
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