摘要
针对机器视觉系统中透视投影导致的钢管、桥梁拉索等圆柱表面缺陷测量不准的问题,提出了一种圆柱曲面透视投影失真的图像校正方法。该方法在提取圆柱成像区域、明确横向和轴向方向的基础上,基于圆柱曲面的透视投影特性,将产生的失真分解为轴向变形和横向变形,利用系统成像参数和圆柱半径建立校正图像与原图像的坐标对应关系,通过最邻近插值法进行像素映射实现透视投影失真校正。实验结果表明,该方法对不同直径圆柱的图像均有良好的校正效果,校正后的图像消除了圆柱曲面“近大远小”透视变形和倾斜投影变形;进行棋盘格模拟校正时,6个圆柱棋盘格边长的测量误差从校正前最高的14.9%降低至校正后的1.2%;进行划痕测量时,两种直径的原图像的最大误差分别为78.0%与61.8%,经本文方法校正后,两种直径的最大误差仅为5.9%与5.5%,校正效果显著。
To address the inaccurate measurement of cylindrical surface defects caused by perspective projection in machine vision systems,an image correction method to resolve cylindrical surface perspective projection distortion is proposed.In this method,the image area of the cylinder is first extracted.Then,the transverse and axial directions are determined.On the basis of the perspective projection characteristics of the cylindrical surface,the distortion is divided into axial and transverse deformation.The imaging parameters and cylindrical radius are utilized to establish the corresponding relationship between the coordinates of the original image and the those of the corrected image.The perspective projection distortion is corrected by pixel mapping and nearest neighbor interpolation.The experimental results demonstrate that the proposed method affords a good correction effect on images of different-diameter cylindrical surfaces.Both near-large and far-small perspective deformation and oblique projection deformation are eliminated in the corrected images.For the checkerboard simulation correction,the measurement error for the side length of the six cylindrical checkerboard squares decreases from a highest of 14.9%before correction to 1.2%after correction.In a scratch measurement,the maximum errors in the original image of two cylinders of different diameters are 78.0%and 61.8%.After correction using the proposed method,the maximum errors are only 5.9%and 5.5%,respectively.The remarkable correction effect verifies the effectiveness of the method.
作者
夏晓华
李玉强
邹易清
胡永彪
蒋立军
XIA Xiaohua;LI Yuqiang;ZOU Yiqing;HU Yongbiao;JIANG Lijun(Key Laboratory of Road Construction Technology and Equipment,Ministry of Education(Chang'an University),Xi'an 710064,China;Liuzhou OVM Machinery Co.Ltd.,Liuzhou 545006,China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2023年第11期1691-1699,共9页
Optics and Precision Engineering
基金
陕西省重点研发计划项目(No.2019GY-116)
机器人技术与系统国家重点实验室开放研究项目(No.SKLRS-2021-KF-10)
西安市科技计划项目(No.2020KJRC0129)。
关键词
图像校正
圆柱曲面
透视投影
失真
测量
image correction
cylindrical surface
perspective projection
distortion
measurement
