Computer-vision-enabled augmented reality fundus biomicroscopy

Purpose: To guide treatment for macular diseases and to facilitate real-tim e image measurement and comparison, investigations were initiated to permit overlay of previously stored photographic and angiographic images directly onto the real-time slit-lamp biomicroscopic fundus image. Design: Experimental study in model eyes, and preliminary observations in h uman subjects. Methods: A modified, binocular video slit lamp interfaced to a personal com puter and framegrabber allows for image acquisition and rendering of stored images overlaid onto the real-time slit-lamp biomicroscopic fundus image. Development proceeds with rendering on a computer monitor, while constructi on is completed on a miniature display interfaced directly with one of the slit-lamp oculars. Registration and tracking are performed with in-house-de veloped software. Main Outcome Measures: Tracking speed and accuracy, ergonomic acceptability . Results: Computer-vision algorithms permit robust montaging, tracking, regi stration, and rendering of previously stored photographic and angiographic images onto the real-time slit-lamp fundus biomicroscopic image. In model e yes and in preliminary studies in a human eye, optimized registration permi ts near-video-rate image overlay with updates at 3 to 10 Hz and misregistra tion errors on the order of 1 to 5 pixels. Conclusions: A prototype for ophthalmic augmented reality (image overlay) i s presented. The current hardware/software implementation allows for robust performance.