【作者】 王健；

【导师】 刘宏立；

【作者基本信息】 湖南大学 ， 电子科学与技术， 2019， 硕士

【摘要】 近年来,随着机器视觉的飞速发展,工业测量对于精度的要求越来越高。传统的测量仪器已经不能满足三维坐标采集的需要。结构光视觉技术以其简单、快速、准确等特点使其应用在各个领域。结构光视觉技术的最大优势在于它可以快速扫描被测物体并直接获得高精度三维坐标数据,而无需反射棱镜。论文以钢轨紧固件作为研究对象,深入探讨了线结构光三维重构系统的相关技术。将现有的三维测量技术应用到铁路的实际工程背景中,实现了对钢轨紧固件的重构与定位。论文的主要工作如下:(1)对结构光视觉技术的研究现状以及线结构光三维重构系统原理进行详细介绍。分析激光三角测量方法中直接型激光三角法与倾斜式激光三角测量方法的优缺点,根据实际的应用场景,最终选择使用直接型激光三角测量法进行测量。(2)根据线结构光传感器的数学模型,建立图像坐标系、摄像机坐标系以及世界坐标系。分析常用摄像机标定方法的优缺点,并对张氏标定法的原理进行深入研究,结合系统实际实验环境,最终使用张正友标定算法作为本系统的相机标定方法。(3)对光条纹中心线提取算法进行研究与探讨,分别采用灰度重心法、极大值法与Hessian矩阵法进行实验,分析比较三种提取算法的提取效果,最终使用灰度重心法作为本系统的中线提取算法。(4)根据系统运动信息,获得摄像机运动方向信息。将二维像素转化为空间三维坐标,对紧固件进行三维重构。根据紧固件的三维轮廓,提取紧固件螺母圆平面。本文分析比较常见的圆拟合方法,对圆平面进行拟合,定位圆心,并对实验结果进行分析。(5)搭建了钢轨紧固件定位系统平台。利用MATLAB和Microsoft Visual Studio2010等软件开发工具,使用C++编程语言对软件的功能进行设计。并在软件程序上进行圆心定位实验,验证系统的可行性。更多还原

【Abstract】 In recent years,with the continuous expansion of the field of engineering measurement and the requirements for measurement accuracy in 3D design and manufacturing,traditional measuring instruments have been unable to meet the needs of high-precision three-dimensional coordinate acquisition.Compared with traditional measurement techniques,structured light vision technology has great technical advantages,especially in data acquisition.Its high efficiency,fast,accurate and simple features make it widely used in various fields.The biggest advantage of structured light vision technology is that it can quickly scan the object under test and directly obtain high-precision 3D coordinate data without the need for a reflective prism.The paper takes the rail fastener as the research object,and deeply discusses the related technology of the line structure light three-dimensional reconstruction system.Applying the existing 3D measurement technology to the actual engineering background of the railway,the reconstruction and positioning of the rail fasteners is realized.The main work of this paper is as follows:(1)The research status of structured light vision technology and the principle of line structure light 3D reconstruction system are introduced in detail.The advantages and disadvantages of direct laser triangulation method and inclined laser triangulation method in laser triangulation measurement are analyzed.According to the actual application scenario,the direct laser triangulation method is finally selected for measurement.(2)According to the mathematical model of line structured light sensor,image coordinate system,camera coordinate system and world coordinate system are established.The advantages and disadvantages of common camera calibration methods are analyzed,and the principle of Zhang Zhengyou’s calibration algorithm is introduced in detail.Combining with the actual experimental environment of the system,Zhang Zhengyou’s calibration algorithm is finally used as the camera calibration method of the system.(3)The algorithm of extracting the center line of light fringes is studied and discussed.Experiments are carried out by maximum method,gray center of gravity method and Hessian matrix method respectively.The effect of the three algorithms is analyzed and compared.Finally,the gray center of gravity method is used as thealgorithm of extracting the center line of the system.(4)Through the system motion information,the camera motion direction information is obtained.The two-dimensional pixels are converted into spatial three-dimensional coordinates,and the fasteners are three-dimensionally reconstructed.The round surface of the fastener nut is extracted according to the three-dimensional profile of the fastener.The paper analyzes the common circle fitting method,fits the circular plane,locates the center of the circle,and analyzes the experimental results.(5)A rail fastener positioning system platform was built.Using software development tools such as MATLAB and Microsoft Visual Studio 2010,the function of the software is designed with C++ programming language.The center positioning experiment was carried out on the software program to verify the feasibility of the system.更多还原