基于机器视觉的非球面双远心工业镜头设计

摘要

According to the demand for precision measurement of large size parts, a set of double telecentric industrial lens based on machine vision is designed, which can effectively replace the human eye for testing. The system adopts a symmetrical structure consisting of 7 lenses with aperture diaphragm in the center. Two new aspheric surfaces are introduced to improve the imaging quality, and the volume of the system is reduced to the greatest extent, making the total length of the system 292 mm. When the Nyquist frequency is 50 lp/mm, the MTF value of the modulation transfer function is all higher than 0.6,and the tolerance analysis is carried out to meet the imaging requirements. The system working distance is 127.3 mm, the pupil diameter is 300 mm, the depth of field is 80 mm, the maximum distortion is 0. 005% , and the telecentric degree is less than 0.01°,which realizes the design requirements of large aperture, large depth of field, and low distortion and achieves the purpose of double telecentric. The system can be widely used in aerospace, railway bus, automobile and ship production and testing.%根据大尺寸零部件精密测量的需求,设计了一套基于机器视觉的非球面双远心工业镜头,有效地代替人眼进行检测.系统采用7片透镜组成的对称式结构,孔径光阑居正中;引入2个新型非球面提高成像质量,并最大程度的减小了系统体积,使系统总长为292 mm.在奈奎斯特频率为50 lp/mm时,调制传递函数MTF值均高于0.6,并进行公差分析,满足成像要求.系统工作距127.3 mm、入瞳直径300 mm、景深80 mm、最大畸变0.005％、远心度小于0.01°,实现了大口径、大景深、低畸变等设计要求,达到了双远心的目的.该系统可广泛应用于航空航天、轨道客车和汽车船舶领域的生产和检测等环节.