激光与光电子学进展, 2020, 57 (3): 032001, 网络出版: 2020-02-17
基于光场成像的三点式光笔测量方法 下载: 1242次
Three-Point Light Pen Measurement Method Based on Light Field Imaging
光计算 光场成像 光笔 数字重聚焦 聚焦测距 透视三点 optics in computing light field imaging light pen digital refocusing focus ranging pespective-three-point
摘要
针对现有三点式光笔测量系统采用透视三点(P3P)算法求解出现多解的问题,提出一种基于光场成像的三点式光笔多解排除算法。对光场相机中心子孔径进行高精度内参标定;通过光场相机采集图像,运用P3P算法获得提取的中心子孔径图像中两组光笔激光点的摄像机坐标;利用高斯成像公式计算两组解的深度值,将区域窗口光场重聚焦到两组深度平面。选取合适的清晰度评价方法对两幅图像的清晰度进行比较,获得最终的光笔位姿矩阵,解算笔尖的三维坐标。选用精密三坐标平移台移动距离作为比对基准,实验结果表明:本实验测量系统与三坐标平移台在X、Y、Z方向的最大位置差值分别为0.35,0.40,0.54 mm,该结果与运用四点重投影选取正解的结果相同,证明了所提出的方法的有效性和准确性。
Abstract
Because the existing three-point light pen measurement system using pespective-three-point(P3P) algorithm to solve an equation is prone to the problem of multiple solutions, this paper proposes a three-point light pen multi-solution elimination algorithm based on light field imaging. First, high-precision internal reference calibration is performed for the central aperture of the light field camera. Second, the image is acquired by the light field camera, and the camera coordinates of the two sets of light pen laser points in the extracted central subaperture image are obtained by using the P3P algorithm. The Gaussian imaging formula is used to calculate the depth values of the two sets of solutions, and then the regional window light field is refocused to the two sets of depth planes. Finally, the appropriate sharpness evaluation method is selected to compare the sharpness of the two images, and the final light pen pose matrix is obtained to solve the three-dimensional coordinates of the pen tip. In this paper, the moving distance of the precision three-axis translation stage is selected as the comparison benchmark. The experimental results show that the maximum position differences between the experimental measurement system and the three-axis translation stage in X, Y, and Z directions are 0.35, 0.40, and 0.54 mm, respectively. At the same time, the same positive results are obtained by using four-point re-projection, which proves the validity and accuracy of the proposed method.
于之靖, 郑建文, 陶永奎, 吴军. 基于光场成像的三点式光笔测量方法[J]. 激光与光电子学进展, 2020, 57(3): 032001. Zhijing Yu, Jianwen Zheng, Yongkui Tao, Jun Wu. Three-Point Light Pen Measurement Method Based on Light Field Imaging[J]. Laser & Optoelectronics Progress, 2020, 57(3): 032001.