Global vessel symmetry for optic disc detection in retinal images

Optic disc (OD) detection is an important step in developing computer aided screening systems suitable for glaucoma analysis. In this paper, we present a new method for automatic optic disc detection in retinal (fundus) images. The method is based upon the distribution of major blood vessels. The blood vessels originate from the OD and their random distribution pattern can be approximately divided into two halves by a global symmetric axis passing through the centroid and near the optic disc. We detect this symmetry axis by using partial Hausdorff distance (PHD) measure. Then, the OD center is detected by applying the brightness property of the optic disc region. The proposed method is evaluated and compared on DRIVE, STARE and HRF databases. The average performance of the proposed method is found as: 97.5% in DRIVE, 97.5% in STARE and 100% in HRF database.