Retinal fundus images segmentation and analysis

The cup to disk ratio (CDR) is the key indicator of this disease for detecting Glaucoma. It is observed that the CDR for healthy subjects lies in 0.233-0.306 range and for Glaucoma patients it lies in the range of 0.355-0.503. These values are in accord with the gold standards. Similarly for DR, in the first stage, gray-scale image is extracted from the colored image using Principal Component Analysis (PCA) in the preprocessing step. The contrast enhancement by the Contrast Limited Adaptive Histogram Equalization (CLAHE) highlights the retinal blood vessels in the gray-scale image. These operations help in extracting retinal blood vessels in the disc and non- disc region of the image. The results are compared with state of art methods such as watershed transform.