【作者】 王文格；

【导师】 孙宗禹；

【作者基本信息】 湖南大学 ， 机械制造及其自动化， 2003， 博士

【摘要】 大型汽车覆盖件模具及其冲压件的三维测量是汽车设计制造中的关键技术之一，传统三维测量技术速度慢、量程受限、操作不方便。而基于光学、数字图像与计算机视觉的测量技术能快速、准确地获取物体的三维信息，因此开展本课题研究具有重要的理论意义和实用价值。 本文在分析研究大量相关技术和文献的基础上，针对目前存在的问题，采用理论分析与实验研究相结合的方法，对集成光学、数字图像处理和计算机视觉信息的大型复杂曲面便携式快速三维测量中的关键技术进行了较深入系统的研究。 论文首先建立了摄像机模型，分析比较了几种不同的摄像机定标方法、极线几何约束关系和基础矩阵的多种计算方法，提出了一种结构再投影平面模板摄像机标定算法。 论文提出了一种集成多目运动视觉特征点测量、数字相移条纹投影曲面片测量和最近点迭代配准拼接的大型三维曲面测量新方法，具有快速、便携和量程大的特点，与目前的集成系统相比，曲面配准拼接精度不依赖高精度的特征点测量，而是采用多目运动视觉特征点测量结果作曲面初始配准拼接，然后再通过最近点迭代法实现精确拼接。 论文研究了一种基于人工特征图标的图像间特征点自动匹配新算法，较好地解决了对应点匹配问题。首次将人工图标引入视觉计算，通过提取人工特征点，采用灰度相关法进行初始匹配，再利用松弛法、鲁棒估计基础矩阵恢复极线约束和结构再投影法剔除错误匹配点、寻找更多匹配对。经实验验证该算法快速、准确、鲁棒性好、基本没有误匹配。 论文对图像特征点提取进行了研究；分析研究了立体视觉和近景摄影测量三维测量算法；首次提出采用循环计算方法、剔除2D和3D错误点的运动视觉特征点三维测量算法。实验表明该算法能消除图像匹配点错误对结果带来的影响，鲁棒性较好。 论文最后系统研究了基于数字相移条纹投影曲面三维测量方法，创造性地提出了一种减小测量误差的非线性校正算法，取得了预期的效果；同时对相位去包裹算法进行了较深入研究，提出了一种噪声图像相位去包裹方法；实验表明该方法能减小非线性测量误差，自动避开噪声点和间断点，获得了满意的结果。 由于视觉三维测量研究涉及多学科交叉，存在的问题很多，本文仅就设计思想中的几个关键技术进行了研究，还有一些问题需进一步探讨。更多还原

【Abstract】 In automotive industry, there is a need for accurately measuring the 3-D shapes of die and stamped parts of the large-scale complex car body to speed up product development and ensure manufacturing quality. 3-D measurement systems based on optics and computer vision can provide a non-contact, rapid and reliable measurement compared to conventional 3-D coordinate measurement machines. It is valuable to research vision measurement technology.Based on analyzing the existing research works and literatures of 3D vision measurement, aimed at the existing problems, some crucial technology for large-scale surface 3D measurement based on optics, digital image processing and computer vision are theoretically and experimentally studied in this dissertation. Camera model is established above all. Some methods of camera calibration, the epipolar geometry constrain and various computational techniques of fundamental matrix are systematically analyzed and compared in this thesis. We present a camera calibration algorithm by viewing a plane using reprojection.A novel approach of large-scale surface 3D measurement is proposed which combine multiple view motion vision measurement, digital fringe projection measurement and iterative closest point registration. The measurement techniques is rapid, portable, easy to operate and large measurement area. Compared with the existing methods, the accuracy of surface merged is not dependent on high accuracy of feature point measurement, but determined by iterative closest point registration.We have studied a new algorithm of feature point correspondence based on artificial landmark, solved the problem of feature point match between images. Artificial feature landmark is first leaded into vision computation in this paper. Our approach is to extract marker points and to use correlation to find an initial set of matches, then use relaxation, robust recover epipolar geometry and reprojection to discard false matches in this set and find more matches. The algorithm is rapid, accurate and no false match points in the main.Feature extraction algorithm, one of the most important areas in computer vision, is studied and algorithms of stereo and closed range photogrammetry are analyzed. This thesis proposes an algorithm of feature point 3D vision measurement from motion to use cycle computation and discard 2D & 3D outliers for the first time.Experiment state clearly the effects of outliers can be removed by the algorithm which is robust and better results have been obtained.Finally, a new 3D surface ranging method based on a digital fringe projection and shifting technique is systematically studied and non-linear rectification algorithms which reduce measurement error is proposed. At the same time, the noise-immune phase unwrapping algorithm is deeply studied and a new algorithm for phase unwrapping of phase map is proposed. Experiment make known the algorithm can reduce measurement error, bypass the noise points automatically, solve the problem of the shade sheltering or cavity, overcome the error propagation problem and better results have been obtained.Owing to 3D vision measurement relating to many intersect disciplines, a lot of technique questions exist still. This thesis only involves some crucial techniques in this field, we make further study to some questions left.更多还原