Retinal image segmentation and 3D visualization

One of the novel methods prevailing in the clinical world for early detection of glaucoma progression is determining the deformation of optic nerve head based on fundus images. In order to overcome the subjective hand-sketched markings recorded in a clinic, research into various methods for automatic detection of the optic disc and cup boundaries in glaucomatous fundus images began to evolve. One of the earlier research work was based on creating a 3D model of the optic nerve head for glaucoma assessment. A recent approach based on demons non rigid registration method estimates the cupping of the optic disc by finding the cup boundary instead of the entire cup region, by using optical flow technique. This is achieved by quantitative estimation of depth discontinuities along the boundary region by computing the relative motion field between sequential images. Sequentially acquired monocular fundus images can be used in the estimation of depth discontinuity instead of stereo image pairs required for 3D visualization. A comparison of the cup boundary parameters along with cup to disc diameter ratio (CDR) and cup to disc area ratio (CAR) values estimated by the above two approaches is presented and validated with manual marking of the cup boundary by ophthalmologists.