Robust computer-assisted laser treatment using real-time retinal tracking

We propose a new computerized system to accurately guide laser shots to the diseased areas within the retina based on predetermined treatment planning. The proposed system consists of a fundus camera interfaced to a computer that allows real-time capturing and processing of a sequence of images at video frame rates. The first image in the sequence is used as a reference for manual treatment planning. A new segmentation technique was developed to discern the blood vessel tree in which we extract the boundaries of the wide vessels as well as the whole lumen of smaller ones. The core of wide vessels is then obtained by correlating the image with a 1-D Gaussian filter in two perpendicular directions and thresholding the result. A fast registration technique is proposed to automatically track the motion of segmented areas within the subsequent images in the sequence. In this technique, points satisfying certain developed significance conditions are chosen as landmarks in the reference frame. Using the extracted set of corresponding points in the subsequent image frames, we can accurately align image frames to compensate for eye movements and saccades. The new technique has the potential to significantly improve the success rates in this type of treatment.