Geometry-Based Optic Disk Tracking in Retinal Fundus Videos

Fundus video cameras enable the acquisition of image sequences to analyze fast temporal changes on the human retina in a noninvasive manner. In this work, we propose a tracking-by-detection scheme for the optic disk to capture the human eye motion on-line during examination. Our approach exploits the elliptical shape of the optic disk. Therefore, we employ the fast radial symmetry transform for an efficient estimation of the disk center point in successive frames. Large eye movements due to saccades, motion of the head or blinking are detected automatically by a correlation analysis to guide the tracking procedure. In our experiments on real video data acquired by a low-cost video camera, the proposed method yields a hit rate of 98% with a normalized median accuracy of 4% of the disk diameter. The achieved frame rate of 28 frames per second enables a real-time application of our approach.