结合互相关和B样条插值的激光三角光斑定位  

Laser triangular spot positioning combined with cross-correlation and B-spline interpolation

作　　者：董晶鑫 万松 周丽平[3] 赵辉[1] 陶卫[1] DONG Jingxin;WAN Song;ZHOU Liping;ZHAO Hui;TAO Wei(School of Electronic Information and Electrical Engineering,Shanghai Jiaotong University,Shanghai 201100,China;Shanghai West Hongqiao Navigation Technology Co,Ltd.,Shanghai 201100,China;Shanghai Institute of Satellite Engineering,Shanghai 201700,China)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海201100 [2]上海西虹桥导航技术有限公司,上海201100 [3]上海卫星工程研究所,上海201700

出　　处：《光学精密工程》2023年第7期1000-1011,共12页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.51975374)。

摘　　要：激光三角光斑定位通常受到像点光斑偏态的影响,为提高激光三角位移传感器的测量精度和物面适应性,在分析激光三角光斑的偏态特征的基础上,针对偏态特性提出了一种基于互相关和非均匀有理B样条插值的光斑定位算法。对光斑信号采取时域和空域相结合的滤波处理方法,降低外部噪声干扰。引入邻域标定光斑进行互相关运算,充分利用光斑偏态分布的灰度和位置相似性约束,确定像素级相关系数分布。最后,对相关系数序列进行三次非均匀有理B样条插值细分,实现亚像素级光斑质心定位。在激光三角位移传感器中验证算法,实验结果表明:该算法通过结合互相关和非均匀有理B样条插值细分,将测量重复性误差降低至0.4μm,精度相对于传统定位算法显著提高;同时,在互相关算法中采用的邻域标定光斑模板不仅容易获取,几何相似度更高,而且对不同物面特性的适应性更强。本文方法精度高、适应性强,为有效提升激光三角位移传感器的性能提供了新的技术路径。Laser triangulation spot location is usually affected by the skewness of the image spot.To improve the measurement accuracy and surface adaptability of the laser triangulation displacement sensor by analyzing the skewness characteristics of the laser triangulation spot,this paper proposes a novel spot location algorithm based on cross-correlation and non-uniform rational B-spline interpolation.First,a filtering method combining time and space domain is adopted for the spot signal to reduce external noise interference.Subsequently,the calibration spot is matched to perform the cross-correlation operation,and the pixel-level correlation coefficient distribution is determined by maximizing the grayscale and position similarity constraints of light intensity distribution.Finally,the correlation coefficient sequence is subdivided by cubic non-uniform rational B-spline interpolation to achieve sub-pixel centroid location.Furthermore,the algorithm is verified in the laser triangulation displacement sensor,and the obtained results indicate that the measurement repeatability error is reduced to 0.4μm by combining cross correlation and non-uniform rational B-spline interpolation subdivision.Compared with the conventional positioning algorithm,the accuracy is significantly improved;the neighborhood calibration spot template adopted in the cross-correlation algorithm is not only easy to obtain,with higher geometric similarity,but also more adaptive to different object surface characteristics.In general,this method exhibits high precision and strong adaptability,which provides a novel technical approach to effectively improving the performance of laser triangular displacement sensors.

关 键 词：激光三角法 光斑中心 定位误差 互相关 非均匀有理B样条 

分 类 号：TP274.[自动化与计算机技术—检测技术与自动化装置]