单目线结构光三维重建系统标定方法研究  

Research on the calibration method of monocular camera line structured light three-dimensional reconstruction system

作　　者：孙超[1] 石久烨 王梅渊 丁建军[1] SUN Chao;SHI Jiuye;WANG Meiyuan;DING Jianjun(School of Intelligent Manufacturing,Jianghan University,Wuhan 234000,China)

机构地区：[1]江汉大学智能制造学院,湖北武汉430056

出　　处：《光学技术》2024年第6期698-705,共8页Optical Technique

基　　金：国家重点研发计划基金资助项目(2018YFD1100104);湖北省教育厅教学研究项目(2022277);江汉大学校级科研基金资助项目(2022XKZX32);江汉大学研究生科研基金资助项目(KYCXJJ202302)。

摘　　要：结构光三维重建系统中相机标定是一项关键研究,圆形标定板被广泛应用于相机标定,在实际标定过程中圆标定图像因相机透视作用而变成椭圆,又因圆形标志边缘像素模糊影响相机标定精度,因此提出一种基于亚像素边缘检测与透视投影的相机标定方法。首先,利用自适应阈值的Canny算子获取标定板圆特征点的边缘,根据边缘像素点特征关系进行插值亚像素细化,拟合椭圆获取中心点;然后通过透视投影变换将椭圆特征点投影成近似标准圆,提取圆心坐标后再反透视投影回原图像;最后使用张氏方法对实际图像中的特征点坐标进行相机标定。实验结果表明,所提方法相较于传统方法的重投影误差降低了43.8%,标准块的三维测量均方根误差最小是0.1316mm,测量误差在0.1~0.5mm之间,满足工业测量要求。Camera calibration is a crucial aspect in structured light three-dimensional reconstruction systems,and circular calibration boards are widely employed for camera calibration.During the actual calibration process,the circular calibration images are transformed into ellipses due to the perspective effect of the camera.Additionally,the blurring of edge pixels of circular markers affects the precision of camera calibration.Therefore,a camera calibration method based on subpixel edge detection and perspective projection is proposed.Firstly,the Canny operator with adaptive thresholding is employed to extract the edges of the circular features on the calibration board.Sub-pixel refinement is achieved through interpolation based on the relationships among the edge pixel characteristics,leading to the determination of the ellipse's center.Subsequently,the ellipse feature points are projected into an approximately standard circle using perspective transformation.After extracting the coordinates of the circle center,the points are inversely projected back to the original image.Finally,the Zhang's method is employed to calibrate the camera based on the coordinates of the feature points in the actual images.Experimental results demonstrate that the proposed method reduces the reprojection error by 43.8% compared to traditional methods.The root mean square error for the three-dimensional measurements of standard blocks is minimized at 0.1316mm,and the measurement error ranges between 0.1mm and 0.5mm,meeting the requirements for industrial measurements.

关 键 词：相机标定 三维测量 亚像素 重投影误差 圆标定板 

分 类 号：O439[机械工程—光学工程] TP391.41[理学—光学]