Automatic detection of fovea using property of vessel free region

Accumulation of blood and its constituents over fovea of the retina lead to irreversible vision degradation in Diabetic Retinopathy (DR). Thus, fovea location contains very vital information in automated analysis. In this study, we have developed a simple approach for identification of fovea location. The main advantage of the method is that it does not require prior knowledge of the spatial relationship of optic disc location. The algorithm first searches for the fovea region considering the information that fovea is devoid of blood vessels. Later, dark intensity property of fovea is utilized for its detection from the region of interest. The method requires detection of blood vessel network and then search for vessel free region. Various morphological image processing tools are explored in different color planes for the successful execution of the method. The algorithm is tested on 759 images of DRIVE, DIARETDB0, DIARETDB1, LOCAL, MESSIDOR and HRF databases containing both normal and pathological cases of DR, with efficiency of detection obtained at 100%, 96.85%, 97.67%, 98.46% 96.25% and 100% respectively. The overall accuracy is 98.21%.