Blood vessel tracking technique for optic nerve localisation for field 1-3 color fundus images

This paper considers the problem of locating the optic nerve center, a place where the blood vessel and nerve emanate. Our algorithm first identifies the main blood vessel, which is characterized by large width and dark red color, by using amplitude modified second-order Gaussian filter. The optic nerve center is then found by tracking along this main blood vessel to a convergence point. 80 ocular fundus images of various spatial resolutions with and without disease conditions were tested and a success rate of 86% for finding the optic nerve is achieved. It should be stressed that the by-product of this algorithm, i.e. the main blood vessel found, can be used to segment the entire blood vessel network by exploiting their interconnectivity.