Abstract: Optic disc (OD) location plays an important role in automatic diagnosis of diabetic retinopathy. Medical image analysis and processing has great significance in the field of medicine, especially in non-invasive treatment and clinical study. Changes in optic disc shape and area may indicate disease processes, particularly glaucoma, and accurate identification of the disk boundary may be used to quantify changes. In this paper we are presenting the preprocessing step which will be beneficial further to calculate the cup to boundary ratio of optic disc. This paper presents technique for finding location of optic disc from digital retinal image. The optic disc pixel (ODP) should first determine for further processing. The optic disc pixel (ODP) can be further used for finding location of optic disc. Three methodologies for finding optic disc pixel and finally one voting algorithm for final optic disc pixel are presented in this paper.

Keywords: optic disc pixel (ODP), maximum variance method, maximum difference method, low pass filter method.