Simultaneous automatic detection of optic disc and fovea

Automated localization of the optic disc and fovea are important in the field of analysis of fundus images. We introduce a simultaneous detection method for optic disc and fovea with an enhancement and correction step. In the first step, a set of features are extracted from the color fundus image, and the relationship between the feature set and a distance variable d is established during training phase. For a test image, the same set of features is measured and the distance to the optic disc and fovea can be estimated using k-nearest-neighbor regression. A probability image is generated during this step. In the second, a second k-nearest-neighbor regression is applied on the probability image. Detected high likelihood regions from the first step can be enhanced only if they satisfy the trained relationship. The detected regions that do not get support from the other detected structure will be suppressed. 150 color fundus images were used to train the system. 50 color fundus images were used to test the system. The distance error for the optic disc is 9.8±8.3 pixels. The distance error for the fovea is 13.7±6.6 pixels.