Comparison of colour spaces for optic disc localisation in retinal images

The location of the optic disc is of critical importance in retinal image analysis. In this work we improve on an approach introduced by Mendels, Heneghan and Thiran (1999) which localises an optic disc region through grey level morphology, followed by snake fitting. We propose and implement both the automatic initialisation of the snake and the application of morphology in colour space. We examine various methods of performing the morphology step (to remove the interference of blood vessels) and compare them against each other. We demonstrate that our proposed simple Lab colour morphology method is particularly suitable for the characteristics of our optic disc images. Results indicate 90.32% average accuracy in localising, the optic disc boundary.