Automated localisation of optic disc in retinal colour fundus image for assisting in the diagnosis of glaucoma

Abstract

Optic disc (OD), especially its diameter together with optic cup diameter can be used as a feature to diagnose glaucoma. This study contains two main steps for optic disc localisation, i.e. OD centre point detection and OD diameter determination. Centre point of OD is obtained by finding brightness pixel value based on average filtering. After that, OD diameter is measured from the detected optic disc boundary. The proposed scheme is validated on 30 healthy and glaucoma retinal fundus images from HRF database. The results are compared to the ground truth images. The proposed scheme obtains evaluation result (E) for healthy and glaucoma images is 0.23 and 0.21, respectively. Evaluation result (E) shows the ratio between the average distance of OD centre point obtained by proposed method and that of the ground truth divided by average difference between OD diameter by proposed method and that of the ground truth. The lesser the value of E the better the performance of the method in detecting OD centre point and determining the OD diameter. Therefore, these results indicate successful implementation of automated OD localisation by detecting OD centre point and determining OD diameter in healthy and glaucoma images. Moreover, this scheme has a potential to be implemented in the development of a computerised glaucoma diagnosis system.