# Extracting Retinal Anatomy and Pathological Structure Using Multiscale Segmentation
## 3 Experiments
### Data Preparation
#### 3.1.1 Public Database  
The existing retinal fundus database has a complete DRIVE library, DIARETDB0 library, DIARETDB1 library, MESSIDOR database, e-Optha EX and e-Optha MA library, and a STARE library. Each library has a blood vessel labeling database. Basically, features other than vascular features are missing in these databases.  
The DRIVE database [27] consists of 40 color retinal fundus images captured by a Canon non-mydriasis 3 CCD camera with a resolution of \(768\times 584\), \(45^{\circ}\) FOV, and 8-bit channels per color. The database contains 33 healthy states and seven pathological retinal fundus images. The set of images is divided into a training set and a test set, both of which contain 20 images. The database provides true annotation of blood vessels for the test set. However, the data in the dataset are limited, and the image resolution is single, which is not ideal for additional fundus image testing. The DIARETDB0 and DIARETDB1 databases [28] contain 130 color retinal fundus images. The 130 retinal images available in the database include 110 markers depicting diabetic retinopathy (e.g., hard exudate, soft exudate, micro aneurysm, or hemorrhages). The images consist of 20 normal retina images. The DIARETDB1 database consists of 89 colored retinal fundus images. The 84 retinal images available in the database contain mild signs of diabetic retinopathy, including exudates, and the remaining five are healthy retinal images. However, these labels only contain relevant areas of the lesion in the retinal image.  
The MESSIDOR database [29] consists of 1200 retinal fundus images taken with a Topcon TRC NW6 non-mydriasis fundus camera with \(1440\times 960\), \(2240\times 1488\) and \(2304\times 1536\) pixels. This database provides diagnostic results for various retinal images, but the database does not provide a reference standard for segmentation of fundus retinopathy.  
The e-Optha EX and e-Optha MA databases are described in [30]. The e-Optha EX database consists of 82 retinal fundus images with 35 healthy retinal images and 47 pathological retinal images with pathological retinal images and mild exudate composition associated with moderate and severe diabetic retinopathy. The e-Optha MA database consists of 233 healthy retinal fundus images and 148 images with MA or small hemorrhage. These annotations are useful for accurately assessing the efficiency of exudate and MA segmentation methods. Unfortunately, there is no indication of common features like the cup optic disc or macula.  
The STARE database [31] consists of 400 color retinal fundus photographs with a resolution of \(605\times 700\). This database provides diagnostic results for diabetic retinopathy based on a single retinal fundus image, but it does not contain areas of various retinopathy structures, such as exudates and roth spots. Moreover, after careful comparison of the data, database labeling is very different from the original image, while edge processing has insufficient detail, which has a serious impact on the training results. After a detailed comparison and fitting, only 20 groups of retinal data have reference values.  
In summary, the open source benchmark database has the following limitations: (1) contains a limited number of retinal images and the pixel resolution is generally low; (2) contains only clear contrast and original retinal images; (3) does not contain ground-truth information, e.g., labeling of all the retina's features; (4) the annotations are significantly different from the original ones and some have no annotation detail.