Non-Compactness Attribute Filtering to Extract Retinal Blood Vessels in Fundus Images

Retinal Image Source

The proposed method are tested and evaluated on DRIVE database that is publicly available and consists of 40 colored retinal images. The DRIVE that stands for Digital Retinal Images for Vessel Extraction (DRIVE) was established by Staal et al. (2004). Each image of DRIVE has resolution of 565x584 pixels, and stored in GIF format.

The images of DRIVE database consists of 20 training images and 20 test images. One benefit of using DRIVE is the available reference images resulted from the manual segmentation procedure. The reference images are required to calculate the accuracy of the proposed method. Each training image has one reference image that was created by an observer, while each test image has two reference images created by two different observers. Our experiment is not related with the training procedure. Hence, we used 40 reference images created by the first observer. As it is mentioned in their web site, the observers were instructed and trained by an experienced ophthalmologist. They were asked to mark all pixels of the expected vessel. Figure 1a shows one of the retinal images of the test images, while Figure 1b, and Figure 1c, respectively, show the corresponding images created by first observer and the second observer.

Figure 1.

(a) An image of the test images of DRIVE database, (b) and (c) the corresponding images of the image in (a) created by the first observer and the second observer