Automated segmentation of optic disc area using mathematical morphology and active contour

Optic disc area is a circular and quite distinct bright region in a digital colour fundus image. This paper provides new method to get an optic disc area automatically. Our method works with some steps. In the first step, the red channel is extracted. Then, the optic disc area is localised using circular average filter to detect the candidate of optic disc point. This point is used to establish the region of interest (ROI). After creating the ROI, multiple bottom hat transformation is employed to detect the blood vessels. To remove blood vessel regions, the result of multiple bottom hat transformation is added to ROI image. Before segmentation is performed, image smoothing is done using average filter. The method is tested on forty different optical disc images from DRION database. Our proposed method achieves an average level of sensitivity, specificity and accuracy of 96.12%, 94.36 % and 94.71%, respectively. This indicates that the proposed algorithm successfully detects and segments the optic disc area and is able to be implemented as measurement for the projection line to get the centre of the fovea.