结构光场光束直线跟踪的两步标定方法

Two-stage calibration method based on ray beeline tracking in structured light field

为了实现结构光系统的三维重建,针对传统标定方法结构复杂、标定过程繁琐等问题,提出一种基于光束直线跟踪的两步标定方法。本文方法首先在前后两个平面上分别对投射侧模式上的每个检测点进行标定,建立投射侧光线方程;然后在前后两个平面上分别对平面上的每个目标点建立接收侧CCD的光线方程。在三维测量时,光场中的一个点分别映射为投射侧和接收侧前后平面上的两个点,连接前后平面上的两个点各得到一条空间直线,通过求解两条空间直线的交点即可求得三维空间点的坐标。分析了系统结构在标定时可能产生的误差,系统误差主要来自角度偏移和水平偏移,并提出了误差解决方案。实验结果表明,与传统的基于针孔模型的标定方法相比,本文方法无须考虑系统的成像模型及其参数求解,简洁、高效。标定产生的景深相对误差小于0.2%,能够改善结构光系统的几何标定精度。

In order to achieve three-dimensional reconstruction in structured light system,aiming at the issues of traditional calibration approach,such as complicated structure,cumbersome calibrating proces s,a two-stage calibration method based on ray beeline tracking is proposed.Firstly,by calibrating respectively each detection point in a pattern image projected on the front and rear planes at projection side,the ray equation at the projection side is esta b lished.Then,the ray equation at the reception side （CCD） is established by obtaining respectively the target points on the front an d rear planes.During three-dimensional measuring,a point in light field maps two points located on the front and rear planes at the projection and reception sides.A straight line is established by connecting two points,respectively.Three-dimensional coordinates by solving intersection point of two space lines can be achieved.This paper has analyzed the system structure error,which mainly comes from the angle deviation and horizontal offset,and the error solution is presented.The experimental results show that co mpared with traditional calibration method based on pinhole model,the presented method does not need to consider the imaging model and its parameters,which is concise and efficient. The relative error of the depth of field generated by the calibration is less th an 0.2%,which can improve the geometric calibration accuracy of structured light systems.