用于交通监控系统的光学成像镜头的设计

Design of Optical Lens for Traffic Surveillance System

设计一种用于交通监控系统的宽波段大孔径光学成像镜头,利用红外光的"大气窗口",可在黑暗中或能见度不佳的环境中得到清晰的图像。为了对近红外光与可见光成像,采用CCD作为图像传感器,选用的CCD像元尺寸为4.65μm,其分辨率极限为110lp/mm。镜头的F数为1.6,视场角为16.8°,中心波长为880nm的近红外光,工作波段为400～1000nm。通过计算光学镜头的参数,选用松纳型作为镜头初始结构,通过软件优化,在110lp/mm空间频率处所有视场的调制传递函数(MTF)值超过0.3,最大畸变小于0.1%。

The design of a wide-band and large-aperture optical lens for traffic surveillance system is presented.By utilizing the atmospheric window of infrared light,clear images are achieved in the dark or poor visibility conditions.To use near-infrared and visible light to image,the charge coupled device （CCD） is adopted as the image sensor of the lens with pixel size of 4.65 μm and limiting resolution of 110 lp/mm.F-number of the lens is 1.6,the field of view （FOV） is 16.8°,the center wavelength is 880 nm and the operating wavelength range is from 400 nm to 1000 nm.After calculating the parameters of optical lens,Sunnah type is selected as the initial structure.Through optimization,the lens has an excellent imaging performance.The modulation transfer function （MTF） is more than 0.3 at the spatial frequency of 110 lp/mm,and the maximum distortion is less than 0.1%.