Hough-based registration of retinal images

Many low-vision people have impaired visual function due to macular scotomas. When scotomas involve the fovea, the low-vision patient must use an eccentric retinal area. Training may help some of these patients compensate for their scotomas. Using a scanning laser ophthalmoscope (SLO), ophthalmologists can measure scotomas and train the patients to use an appropriate retinal area for visual tasks. This task is difficult because the patients may move their eyes consciously or unconsciously during inspection or training. We present a Hough-based registration method combined with feature-based SSD technique to help ophthalmologists perform more accurate and efficient eye registration for inspection and training. Mathematical morphology is used to preprocess each frame to extract a small but relevant set of feature points.