基于线结构光和单应性的点云获取方法  

Point cloud acquisition based on linear structured light and homography

作　　者：吴福理[1] 吴嘉盛 丁维龙[1] WU Fuli;WU Jiasheng;DING Weilong(College of Computer Science and Technology,Zhejiang University of Technology,Hangzhou 310023,China;International College,Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]浙江工业大学计算机科学与技术学院,浙江杭州310023 [2]浙江工业大学国际学院,浙江杭州310023

出　　处：《浙江工业大学学报》2018年第5期522-527,共6页Journal of Zhejiang University of Technology

基　　金：浙江省大学生科技创新活动计划(新苗人才计划)项目(2016R403027)

摘　　要：为获取被测物表面三维点云数据,基于线结构光和平面单应性,提出了一种不需要相机标定的点云获取方法.首先令线结构光扫描被测物表面,以相机采集变形光条纹图像.然后根据事先在光平面中设置的4个控制点的像素坐标和空间坐标,求解光平面从图像坐标系到世界坐标系的变换矩阵.通过该矩阵将线结构光与被测物的截交线,即光条纹,校正透视失真并变换为被测物的截面图,从而获得光条纹上被测点的三维坐标.为验证方法的有效性,分别以球体、圆柱体和长方体为被测物,对该方法进行点云获取精度测试.实验表明:误差在1 mm以内的点数约占总点数的85%,误差在0.5mm以内的点数约占总点数的60%.相比传统的需要相机标定的线结构光测量方法,该方法原理更简洁,鲁棒性更强,可用于以低成本快速搭建三维点云获取系统.In order to obtain the three-dimensional point cloud data of the object surface,in this paper,we describe a camera-calibration-excluded method based on the linear structured light and the homography theory.The linear structured light is used to scan the surface of measured object,and a camera is used to collect the image of the distorted light strip.According to pixel and space coordinates based on four control points previously set in the light plane,the transformation matrix of the light plane from the image coordinate system to the world coordinate system can be calculated.The light strip image could be perspective-corrected and transformed into the cross-sectional view of the object.Then the depth information of the object can be read from this view directly.In order to verify the validity of the method,spheres,cylinders,and cuboids are used as the measured objects.Experiments show that the number of points with error within 1 mm is about 85%of the total number of points,and the number of points with error within 0.5 mm is about 60%of the total number of points.Compared with the traditional methods based on the linear structured light,the principle of this method is much more simple and robust,so that this method can be used to build a point cloud acquisition system rapidly at a low cost.

关 键 词：点云 线结构光 单应性 透视变换 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]