激光与光电子学进展, 2023, 60 (6): 0615004, 网络出版: 2023-03-16
基于亚像素图像拼接的透明元件视觉测量方法
Visual Measurement Method for Transparent Elements Based on Sub-Pixel Image Mosaics
机器视觉 视觉检测 透明光学元件 校正 亚像素 图像拼接 随机采样一致性 machine vision visual inspection transparent optical element calibration subpixel image mosaic random sampling consistency
摘要
针对透明光学元件特征不明显以及机器视觉难以进行大视场、高精度尺寸测量的问题,提出一种基于亚像素图像拼接的视觉测量方案。该方案对相机坐标系与世界坐标系间的旋转角进行标定,获得精确的尺度因子与图像预匹配结果;图像坐标系旋转角校正后小于 ;通过添加网格背景实现透明元件特征匹配。所提基于滑动窗口预匹配、随机采样一致性筛选最佳偏移向量的配准算法,使图像拼接精度达到0.05 pixel,较已有研究明显提升。将该方案应用于透明光学元件视觉检测系统中,在移动精度仅为0.02 mm的条件下,获得了平均误差为0.12 pixel的图像拼接结果,实现了透明光学元件的大视场、高精度尺寸测量。
Abstract
A vision measurement scheme based on sub-pixel image stitching is proposed to solve the problems of unclear features of transparent optical elements, difficulty in the large field of view, and high-precision dimension measurement by machine vision. Furthermore, the rotation angle between the camera coordinate system and the world coordinate system is calibrated in the proposed scheme to obtain accurate scale factors and image-matching results. The rotation angle of the image coordinate system is less than 0.1° after correction. Additionally, feature matching of transparent components is achieved by adding a grid background. The proposed registration algorithm based on sliding window pre-matching and random sampling consistency to screen the best offset vector increases the image mosaic accuracy to attain 0.05 pixel, which is significantly improved compared with the previous studies. The scheme is applied to the vision inspection system of transparent optical elements. Under the condition that the moving accuracy is only 0.02 mm, the image mosaic result with an average error of 0.12 pixel is obtained, and the large field of view and high-precision size measurement of transparent optical elements are realized.
李世林, 戴松新, 胡中文, 季杭馨. 基于亚像素图像拼接的透明元件视觉测量方法[J]. 激光与光电子学进展, 2023, 60(6): 0615004. Shilin Li, Songxin Dai, Zhongwen Hu, Hangxin Ji. Visual Measurement Method for Transparent Elements Based on Sub-Pixel Image Mosaics[J]. Laser & Optoelectronics Progress, 2023, 60(6): 0615004.