基于数字光栅投影结构光的三维重建技术研究

发布时间：2018-04-28 05:54

本文选题：结构光三维测量 + 相位展开　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：近年来计算机视觉技术得到了飞速的发展,三维重建技术是计算机视觉应用中一个较为重要的研究领域,广泛应用于质量控制、逆向设计、文物数字化等众多领域。光栅投影三维测量技术具有速度快、精度高等优点,是主动式非接触光学测量技术中的一个重要研究分支。本文从理论分析和实验实践两方面深入研究了以光栅投影三维扫描为基础的三维重建技术,研究了包括物体表面点云数据的获取和三维点云的配准两方面的技术,开发出一套具有物体全貌测量的三维重建系统。本文的主要研究内容和贡献如下:研究了光栅投影测量模型标定技术。阐述了采用相位光栅投影方法进行三维测量的原理,分析了系统标定中的关键技术。针对相位光栅投影测量常用的圆形阵列靶标提出了基于轮廓提取的具有尺度适应性的特征提取算法。通过分析光栅投影系统非正弦性的产生原因,实现了以多步相移法为基础的投影光栅自校正方法。研究了以相移法和多频外差相位展开技术原理为基础的相位求解技术。针对多频外差法解相位技术中取整操作所带来的跳变误差,提出了使用两步验证的剔除方法。针对实际测量中物体表面的扫描有效区的划分问题,使用相位筛选结合基础的图像处理技术达到了筛选和去噪的目的。研究了散乱点云的配准算法。研究了面向无标志点三维扫描所得到的散乱点云数据的配准拼接算法。在快速粗配准方面,根据法向量夹角特征快速筛选关键点,提出了一种关键点点特征直方图描述子的构建方式,结合刚体变换约束通过RANSAC算法获取了精确的点对应,完成点云的粗配准。在精配准方面,使用一种逐渐放宽的对应点点间距离约束筛选迭代中的最近点对的策略对经典的ICP算法进行了改进,提高了精配准的稳定性和速度。并最终通过实验验证了本文散乱点云配准算法的有效性。设计了由投影仪、摄像机和计算机组成的三维重构系统及系统配套软件。利用Visual Studio 2013集成开发环境开发了重构系统配套软件,系统提供了包括图像采集、系统标定、点云配准等的基本功能模块,以及二维图像处理、点云处理等辅助工具链。实现了光栅投影三维重建系统的完整工作流。
[Abstract]:In recent years, computer vision technology has been developed rapidly. 3D reconstruction technology is an important research field in computer vision application. It is widely used in many fields, such as quality control, reverse design, cultural relic digitization and so on. Grating projection 3D measurement technology has the advantages of high speed and high precision. It is an important research branch of active non-contact optical measurement technology. In this paper, the 3D reconstruction technology based on raster projection 3D scanning is studied in terms of theoretical analysis and experimental practice, including the acquisition of object surface point cloud data and the registration of 3D point cloud. A three-dimensional reconstruction system with object panorama is developed. The main contents and contributions of this paper are as follows: the calibration technology of grating projection measurement model is studied. The principle of three-dimensional measurement using phase grating projection method is described, and the key techniques in system calibration are analyzed. A scale-adaptive feature extraction algorithm based on contour extraction is proposed for circular array targets commonly used in phase grating projection measurement. By analyzing the non-sinusoidal causes of grating projection system, a self-tuning method of projection grating based on multi-step phase shift method is realized. Based on the phase shift method and the principle of multi-frequency heterodyne phase unwrapping, the phase solving technique is studied. In order to solve the jump error caused by the integration operation in the phase technology, a two-step verification method is proposed to eliminate the jump error caused by the multi-frequency heterodyne method. Aiming at the problem of dividing the scanning effective area of the object surface in the actual measurement, the purpose of filtering and denoising is achieved by using the phase filter combined with the basic image processing technology. The registration algorithm of scattered point clouds is studied. In this paper, the registration and stitching algorithm of scattered point cloud data for three dimensional scanning of unmarked points is studied. In the aspect of fast rough registration, according to the feature of normal vector angle, a method of constructing a key point feature histogram descriptor is proposed, and the exact point correspondence is obtained by RANSAC algorithm combined with the constraint of rigid body transformation. Complete rough registration of point clouds. In the aspect of fine registration, the classical ICP algorithm is improved by using a strategy of gradually loosening the distance constraint between corresponding points to filter the nearest pair of points in the iteration, which improves the stability and speed of the fine registration. Finally, the effectiveness of the algorithm is verified by experiments. A three-dimensional reconstruction system composed of projector, camera and computer is designed. The software of reconstruction system is developed by using Visual Studio 2013 integrated development environment. The system provides basic function modules including image acquisition, system calibration, point cloud registration and so on, as well as two dimensional image processing, point cloud processing and other auxiliary tool chains. The complete workflow of grating projection 3D reconstruction system is realized.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41

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