Parameterization Of The Optic Nerve Disk In Eye Fundus Images

Algorithms for interactive and automatic optic nerve disk parameterization are presented in this paper. Parameterization of the optic nerve disk is done by detection of the disk boundaries and calculation of parameters describing it. Automatic and interactive algorithms and user interface are designed and implemented in Matlab (The MathWorks, Inc.) programming environment. Interactive identification of the optic nerve disk boundaries was done by experienced ophthalmologist. Reference points interactively placed by physician on the nerve disk boundary then approximated by ellipse. Those boundaries were used as reference boundaries for the evaluation of automatic boundaries detection algorithm. Automatic algorithm is based on removing of vessels by segmentation and approximation and then using derivative image and verification algorithm to determine boundary location. Optic nerve disk boundary is then approximated by ellipse. Comparison of interactive and automatic algorithms shows that automatic algorithm worked well enough on more than 80% of images (in 300 images dataset).