基于光线模型的成像系统标定与三维测量进展

Progresses on Imaging System Calibration and 3D Measurement Based on Ray Model

标定是成像系统执行精准视觉测量的基础,其目的在于确立三维空间物点与传感平面像点的映射关系。区别于传统的小孔透视模型,主要介绍一种光线模型用于对成像系统的标定与测量。该模型以成像系统聚焦状态下每个像素点均对应空间一条虚拟主光线为前提假设,通过确定所有像素点所对应光线方程的参数即可实现标定与成像表征,从而可避免对复杂成像系统的结构分析与建模,复杂成像系统包括光场相机、大畸变镜头与远心镜头等特殊成像系统。综述了光线模型的基本原理及其标定方法发展,并介绍本课题组基于光线模型的条纹结构光三维测量所取得的部分进展,实验结果表明光线模型可通用于对各类复杂结构成像系统的高精度测量,是校准非针孔透视成像系统的有效模型。

Calibration is the basis of accurate vision measurement in an imaging system, and its purpose is to establish the mapping relationship between object points in three-dimensional space and image points on the sensing plane. Different from the traditional pinhole projective model, a ray model for the calibration and measurement of imaging system is introduced in this paper. The model assumes that each pixel point of the imaging system in focus state corresponds to a virtual primary ray in space. By determining the parameters of ray equations corresponding to all pixels, calibration and imaging characterization can be achieved, thereby avoiding the structural analysis for complex imaging systems and modeling. Complex imaging systems include special imaging systems such as light field camera, large distortion lens, and telecentric lens. This paper reviews the basic principles of the ray model and the development of its calibration methods,and presents some of the progresses made by our team in the 3D measurement with fringe structured light based on the ray model, showing that the ray model can be used for high accuracy measurement of various complex structural imaging systems. It is an effective model for calibrating non-pinhole projective imaging systems.