连铸坯三维测量多线结构光的中心条纹快速提取  

Fast extraction center stripe of multi-line-structured light for three-dimensional measurement of casting slab

作　　者：孙传富 彭涛 陆永刚[2] 徐锟 张之江[1] SUN Chuanfu;PENG Tao;LU Yonggang;XU Kun;ZHANG Zhijiang(Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Shanghai University,Shanghai 200444,China;Metallurgical Baosteel Technology Service Co.LTD.,Shanghai 201999,China)

机构地区：[1]上海大学特种光纤与光接入网重点实验室,上海200444 [2]中冶宝钢技术服务有限公司,上海201999

出　　处：《光学精密工程》2023年第3期380-392,共13页Optics and Precision Engineering

基　　金：国家自然科学基金面上项目(No.61572307)。

摘　　要：在利用多线结构光系统对大尺度连铸坯进行三维测量的过程中,线结构光中心条纹的提取精度是影响三维测量精度的重要因素。提出了一种对传统灰度质心方法进行优化的多线结构光中心条纹提取方法。对连铸坯表面激光横截面不满足高斯分布的线结构光条纹,利用图像背景差分的方式去除环境噪声,并根据线结构光条纹与背景间的灰度变化信息确定线结构光的边界,同时提取线结构光的感兴趣区域。根据光条在梯度方向上的灰度积分比例计算灰度质心法的自适应灰度阈值,利用灰度质心方法处理感兴趣区域提取出光条中心点,最后结合附近半径为5个像素的邻域内所定位的中心点进行质心重提取,获得连铸坯表面光条的亚像素中心坐标。现场测量结果表明:对反射特性不均匀的连铸坯表面的激光条纹光条中心进行提取,最终连铸坯边缘轨迹点的三维测量结果标准偏差在2 mm以内,该方法具有精度高、速度快、鲁棒性强的特点。In the three-dimensional(3D)measurement of large-scale casting slabs using a multi-line structured light system,the accuracy of extracting the central stripe of the structured light is an important factor affecting the final 3D measurement accuracy.In this study,a multi-line structured light center stripe extraction method based on the optimization of the traditional gray gravity method is proposed.For linear structured light stripes projected onto the slab surface whose laser cross-section does not fit a Gaussian distribution,firstly,the environmental noise is removed by analyzing the image background difference.The boundary of linear structured light is determined according to the change in grayscale value between the linear structured light stripe and the background,and the region of interest of structured light is extracted.Then,the adaptive gray threshold of the gray gravity method is calculated according to the gray integral proportion of the light stripe in the gradient direction.The gray gravity method is used to process the region of interest and extract the approximate center point of the light stripe.Finally,the sub-pixel center coordinates of the light stripe are obtained by optimizing the extraction combined with the gravity of the roughly located center point in the neighborhood with a radius of 5 pixels.The experimental results show that this method has high precision,high speed,and strong robustness in extracting the center of the laser stripe on the surface of a casting slab with uneven reflection characteristics.The standard deviation of the 3D measurement results of the final casting slab edge trajectory points is within 2 mm.

关 键 词：三维测量 多线结构光 质心法 光条中心提取 连铸坯 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]