The projection position of tube axis should be calculated accurately when the tube axis is measured using stereo vision. Previous methods for measuring tube axis approximate the centerlines of image contours as the axis projection. This assumption exists errors. In order to obtain the exact projection position of tube axis and to improve the measurement precision of tube axis, the proposed method studied the imaging characteristics of tubes. Firstly, a perspective projection model for any cross section of tube was established to explore the geometric relationship between the contour points of the cross section and their corresponding projection points on space axis. Furthermore, a way to locate the precise projected position on image planes of points laying on axis was presented. A binocular vision system was constructed to measure an aerospace tube. Compared with classical approaches, the repeatability accuracy of the proposed method is same as the former, while the measurement accuracy of the presented method increased by 14.5% on average due to precisely calculating the projection position of axis. It is shown that the proposed method is correct in calculating the projection position of tube axis and can effectively improve the measurement precision of tube axis.
基金资助:航空科学基金项目(2017ZE51062)。
作者简介: 孙军华:博士,教授,博士生导师,主要从事机器视觉、图像处理和模式识别等方面的研究。
引用本文:
孙军华,张悦,程晓琦. 基于轴线投影精确模型的弯管立体视觉测量方法[J]. 航空制造技术, 2019, 62(5): 40-45.
SUN Junhua, ZHANG Yue, CHENG Xiaoqi. A Stereo Vision Measurement Method for Bent Tube Based on Accurate Projection Model for Axis. Aeronautical Manufacturing Technology, 2019, 62(5): 40-45.