基于球面光投影成像的直线位移测量系统  

Absolute linear displacement measurement system based on spherical light projection imaging

作　　者：赵志财 于海[1] 万秋华[1] 梁立辉[1] 张红鑫[1] 曾琪峰[1] ZHAO Zhicai;YU Hai;WAN Qiuhua;LIANG Lihui;ZHANG Hongxin;ZENG Qifeng(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China;Graduate University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院大学,北京100049

出　　处：《光学精密工程》2025年第4期532-541,共10页Optics and Precision Engineering

基　　金：国家自然科学基金项目(No.52075520);吉林省自然科学基金项目(No.20230101111JC);吉林省科技发展计划项目(No.20240302012GX)。

摘　　要：基于图像识别算法的图像式位移测量具有较高的鲁棒性和容错性,是一种新型数字化位移测量技术。为了减小测量系统体积,同时实现高分辨率直线位移测量,设计基于球面光投影成像的直线位移测量系统。首先,采用球面光投影的放大作用,设计球面光投影成像放大光路,并根据光波平面模型对图像传感器采集到的像素灰度值进行补偿。接着,为了在单码道上实现绝对位置测量与编码元素区分,设计伪随机序列的编码方式及基于宽度阈值的译码方法。然后,为实现亚像素级直线位移测量并提高系统精度,设计直线位移细分算法与多质心融合算法。最后,设计实验装置对所提出的方法进行实验验证。所设计的实验装置测量光路高度仅有5 mm。实验结果表明,所提出的方法能在250 mm的量程范围内,实现理论分辨力为5 nm,误差范围为-3.3~3.6μm,补偿后误差范围为-0.6~1μm的直线位移测量。所做的研究,可在减小系统体积的同时实现高分辨力直线位移测量,为开展高分辨力直线位移测量研究提供技术依据。Image-based displacement measurement using image recognition algorithms is a novel digital displacement measurement technology that offers high robustness and fault tolerance.To reduce the volume of the measurement system while achieving high-resolution linear displacement measurement,a linear displacement measurement system based on spherical light projection imaging was designed.Firstly,the magnification effect of spherical light projection was utilized to design the spherical light projection imaging magnification optical path,and the pixel grayscale values captured by the image sensor were compensated based on the optical wave plane model.Subsequently,to achieve absolute position measurement and encoding element discrimination on a single code track,a pseudo-random sequence encoding method and a decoding method based on width threshold were designed.Then,to achieve sub-pixel linear displacement measurement and enhance system accuracy,a linear displacement subdivision algorithm and a multi-centroid fusion algorithm were designed.Finally,an experimental setup was designed to experimentally validate the proposed method.The measurement optical path height of the designed experimental setup is only 5 mm.The experimental results indicate that the proposed method can achieve a theoretical resolution of 5 nm within a 250 mm range,with an error range of-3.3μm to 3.6μm,and after compensation,the error range is reduced to-0.6μm to 1μm.The research conducted can provide a technical basis for high-resolution linear displacement measurement studies while reducing the system volume and achieving high-resolution linear displacement measurement.

关 键 词：球面光投影成像 图像式直线位移测量 高鲁棒性 高容错性 高分辨力 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]