机器视觉检测的低畸变物方远心光学系统设计

Design of Low-Distortion Object Telecentric Optical System Based on Machine Vision Detection

为了提高机器视觉检测的测量精度和测量效率,有效解决动态测量中调焦不准所导致的测量误差问题,以高斯光学和远心光路设计理论为基础,设计出一款物方远心物镜。该物镜焦距为135 mm、物方线视场为45.18 mm、相对孔径为1:8、物方数值孔径为0.011、放大倍率为-0.177、工作距离为102.41 mm、系统总长为145.09 mm。采用光学理论推导以及前后组组合的设计思路,得到系统的初始结构,再进行像差优化。系统优化后的结果显示:系统的调制传递函数(modulation transfer function,MTF)在Nyquist频率70 lp·mm^(-1)处优于0.4,成像畸变低于0.04%,物方远心度低于0.05°。表明该系统结构紧凑,测量精度高,畸变低,成像质量良好,易于装配实现,并且能很好地应用于机器视觉检测领域。

To improve the measurement accuracy and efficiency of machine vision detection,and eliminate the measurement error from inaccurate focus in dynamic measurement,an object telecentric optical system is designed with a focal length of 135 mm,object square field of view of 45.18 mm,relative aperture of 1:8,numerical aperture of object square of 0.011,magnification of-0.177,working distance of 102.41 mm and system total length of 145.09 mm based on Gaussian optics and telecentric optical path design theory.The initial structure of the system is obtained on optical theory derivation using front and back group combination,and aberration optimized.The results of system optimization show that the MTF of the system is better than 0.4 at the Nyquist frequency of 70 lp·mm^(-1),the imaging distortion is less than 0.04%,and the object telecentric is less than 0.05°,proving that the system has the advantages of compact structure,high measurement accuracy,low distortion,good imaging quality,easy assembly and implementation,and good application prospect in the field of machine vision inspection.