基于绝对相位标靶的线阵相机标定方法  

Line-Scan Camera Calibration Method Based on Absolute Phase Target

作　　者：黄淦 邵双运[1] 罗珏婷 Huang Gan;Shao Shuangyun;Luo Jueting(School of Physical Science and Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学物理科学与工程学院,北京100044

出　　处：《中国激光》2024年第2期75-83,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划(2017YFC0805400)。

摘　　要：针对当前线阵相机几何标靶标定精度不足的问题,提出了一种基于绝对相位标靶的线阵相机标定方法。针对线阵相机成像特点,设计了结合相位与格雷码的绝对相位编码标靶。标定时首先由线阵相机获取标靶图像,计算标靶的绝对相位;然后在空间不同位置处摆放标靶,采用辅助面阵相机获取标靶间的相对位置关系,建立线阵相机图像与空间点的精确对应关系;最后采用两步法标定获取线阵相机内两相机间的坐标变换关系。仿真与实验结果表明:标定的最大重投影误差为0.089 pixel,与现有方法相比降低了79.78%,所提方法具有良好的抗噪、抗离焦性。Objective The accuracy of camera calibration directly determines the precision of 3D measurements,underscoring its importance in the research of 3D measurement techniques.Due to the advantages of high speed and high resolution,line-scan cameras are increasingly in demand for 3D measurement applications,necessitating high-precision calibration.Currently,there are two main methods for line-scan camera calibration:dynamic calibration and static calibration.Dynamic calibration is a process that requires the uniform movement of the line-scan camera with a displacement stage,while simultaneously scanning a calibration target,thereby generating 2D images for calibration purposes.Although this method realizes high accuracy,the calibration process is complex and often unfeasible in industrial settings where camera movement is restricted.On the other hand,static calibration depends on a parallel line calibration board,designed according to the principle of projective invariance.This method determines the calibration parameters by calculating the intersection coordinates of camera lines on the calibration target,which is performed by measuring the distance between parallel lines in the images.Static calibration methods reduce calibration costs and improve flexibility.However,they are susceptible to nonlinear mapping errors,insufficient feature information,and low calibration accuracy when the target is out of focus.To address these challenges,in this study,we propose a high-precision calibration method for line-scan cameras based on an absolute phase target.Leveraging the advantages of phase targets,such as high-precision positioning,rich feature points,and robustness against defocus,we design a phase target and calibration method appropriate for line-scan camera calibration.By combining the strengths of phase targets and assistance from a complementary area scan camera,this method establishes an accurate correspondence between line-scan camera images and spatial points via absolute phase information,thereby realizing high-

关 键 词：测量 相机标定 线阵相机 相位标靶 视觉测量 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]