广域视网膜成像技术研究

Research of wide-area retinal imaging technique

针对传统眼底照相机检查不到视网膜边缘的缺陷,提出一种基于Volk角膜接触透镜的免散瞳广域视网膜成像系统。照明充分时,Volk镜头能够达到130°以上的视场。在传统眼底相机的基础上改进照明方式,采用外部环形光纤照明的方式实现视网膜广域照明。增大入射角度消除鬼像的影响,同时避免由环形照明方式导致的中心区域的暗斑现象,被照亮的眼底图像经过接目物镜组消除眼角膜反射造成的杂光并采用手动调焦的方式在CMOS相机上成现清晰的像。图像采集使用(2/3)英寸板面彩色CMOS相机并且实时上传至电脑客户端进行分析、处理、存档等操作,经过后期图像处理后可为各类眼科疾病的诊断、筛查提供清晰、客观的依据。

In view of the traditional fundus camera which can not check the defects of retinaledge,a non-mydriatic wide-area retinal imaging system based on Volk contact lens is proposed. In sufficient lighting conditions,Volk lens can reach more than 130° field of view（FOV）. The il-lumination way is improved based on traditional fundus camera ,nd by the way of using exter-nal annular fiber illumination,the retinal wide-area illumination is realized. The incident angle is increased to eliminate the influence of ghost image,and the dark spot phenomenon in center re-gion can be avoided which is caused by annular lighting meanwhile. The objective lens groliminates the stray light caused by the corneal reflex and uses the manual focusing memake a clear image on the complementary metal-oxide semiconductor （CMOS） camera. The fun-dus images are collected by the colorized CMOS camera with （2/3）7 image acquisition board and then uploaded to the PC terminal in real-time for analyzing, processing, archiving and other oper-ations. Images after post-processing can provide clear, objective bases for the diagnosis andscreening of varied kinds of eye diseases.