基于ICT图像的工件壁厚和圆度误差测量

Wall thickness and roundness error measurements of workpieces based on ICT images

研究基于工业计算机断层成像技术(ICT)图像的工件壁厚和圆度误差测量方法.首先采用Facet模型对ICT图像进行边缘提取,其次采用Freeman链表法将边缘图像中待测壁厚的工件内外壁边缘或待测圆度误差的工件近似圆边缘跟踪出来,最后通过求取内壁链表各点到外壁链表各点的最小距离的平均值得到工件壁厚,或通过最小区域法求得工件圆度误差.通过对仿真和实际的ICT图像进行实验表明:该方法能够准确地求得ICT图像中工件截面的壁厚和圆度误差,特别适合测量工件中封闭内腔的壁厚和内孔的圆度误差.该方法可用于工件制造质量控制,也可用于逆向制造中工件几何尺寸的测量.

Methods for wall thickness and roundness error measurements of workpieces based on Industrial CT images （ICT） were studied. Firstly, Facet model was used for the ICT images edge detection. Next, both inside and outside edge of the wall in the workpieees edge image were tracked out with Freeman list method, the similar round edge of workpiece was also tracked out, then the minimum distances between each points in the inside wall list and each points in the outside wall list were calculated. Finally, the wall thickness can be calculated by calculating the average of the distances, the least region method was applied in the meas- urement of the roundness error. The results on the simulation and the actual ICT images showed that these methods could accurately acquire wall thickness and roundness error of the workpieces in the ICT images. These methods were particularly suitable for the cross - section wall thickness measurement of closed inner cavity and the roundness error measurement of inner annular in the work pieces. They could play an important role in the quality control of manufacturing, and also could be used in the measurement of geometry pa- rameters in inverse manufacturing.