Research On Key Technique Of Wide-area Digital Fundus Imaging Technology

Observing and acquiring images of the peripheral retinal areas plays a key role in the early detection of multiple ophthalmic diseases such as retinopathy of prematurity(ROP).The traditional fundus camera could not applied in the early detection of ROP due to smaller imaging field,patients coordination needed and difficult to obtain the peripheral retinal images.Wide-area digital fundus imaging system is helpful for the early detection and treatment of ROP due to it could observe and obtain images of the peripheral retinal areas.In this paper,we will focus on the portable wide-area digital fundus imaging system and its key technologies,which provides the theoretical support and practical guidance for the development of wide-field digital fundus imaging system.The main achievements in this dissertation are as follows:1.According to the requirements of the early detection of ROP,a portable wide-field fundus imaging system using corneal contact lens and annular distributed fiber optic illumination was proposed.The fundus image could obtained and collected based on the wide-area fundus imaging system and Android terminal were combined by WiFi transmission module,which provides an objective basis for diagnosis of the ROP.2.The model of human eye LIOU was established according to the structure of the human eye and the optical parameters of the refractive media in order to simulate the real environment of wide retinal imaging system.A theory of the near-infrared light source was used as the focusing light source and visible light acted as the imaging light source of the imaging system was proposed on the basis of the spectral characteristics of the human eye,the safety protection standards as well as the working principle of the fundus camera.3.The normal field of view imaging path of fundus with 45° was established according to the ideal object-image relation,and the structure parameters of the imaging optical path were determined.Through the analysis and calculation,the focusing curve with different refraction(-10 D ~ 10D)of human eye was achieved by moving the imaging objective and the image detector simultaneously.The normal optical imaging path based on LIOU was simulated and analyzed in ZEMAX,which can realize the different refractive human eye imaging clearly.4.The imaging and illumination with 90° field of view was established on the basis of using the aspherical and concave-convex corneal contact lens and circular fiber optic illumination in the normal imaging visual field.The key factors affecting wide-area retinal imaging were analyzed.Wide-area imaging and illumination were simulated and analyzed in ZEMAX and Lighttools,and the results showed that the wide-area fundus imaging system met the requirements of wide-area retinal imaging.5.The Android-based retinal imaging system software was accomplished on the basis of Android SDK and the Sony Camera API.The retinal imaging system based on Android was established by combined the wide-area digital fundus imaging system with Android terminal,which realized a portable wide-area digital fundus imaging system.