Optic disk localization using fast radial symmetry transform

Fundus imaging is one of the most frequently used modalities for screening, diagnosis of eye diseases and some vascular abnormalities. Due to its wide availability, automatic evaluation of fundus images offers great potential benefits to current clinical practice. The basis of many automatic evaluations or diagnosis is the segmentation of the eye background, most notably, the detection of the optic disk and the segmentation of the retinal vessel tree. In this work we propose a variant of the fast radial symmetry transform (FRST), adapted to its application in the detection of the optic disk in fundus images. We evaluated and compared the performance of our method to the standard FRST and the similar, gradient based circular Hough transform using 45 images of a high resolution database with gold standard information available. We demonstrated in our experiments that the proposed method outperforms the state-of-the-art algorithms with 0.051 ± 0.073 optic disk diameter localization error in average.