Fast Optic Disc Localization and Extraction in Retinal Fundus Images Using Bitplane Decomposition and Mathematical Morphology

This paper presents an approach to the fast localization and extraction of optic disc from fundus images of the human retina. For the diagnosis of Diabetic Retinopathy and other eye related abnormalities, digital fundus images are becoming increasingly important. This fact opens the possibility of applying image processing techniques in ocular fundus images to facilitate and improve diagnosis in different ways. Optic disc is the major landmark for retinal fundus image registration and is indispensible for the quick understanding of retinal images. For the detection and subsequent extraction of optic disc, we first perform bit plane decomposition to the image. The lower order bit planes are found to carry vital information of the location and boundary of optic disc. Then we locate the exact boundary by means of mathematical morphology. The algorithm has been evaluated on a subset of MESSIDOR1 image database with various visual qualities. Robustness with respect to the changes of the parameters of the algorithm has been examined.