ABSTRACT
In this chapter, a detailed review, analysis, and categorization of retinal vessel segmentation and caliber measurement techniques are presented. The objective is to provide a detailed resource of the algorithms employed for vessel segmentation and width measurement as a ready reference. The key points are highlighted, the differences and performance measures are illustrated, and the advantages and disadvantages of various approaches are discussed. The current trends, the future directions, and the open problems in automated blood vessel segmentation are also discussed. A summary of the publicly available databases of retinal images is also provided as this has stimulated research and innovation in ophthalmology by providing a means of direct comparison between the algorithms of automated retinal image analysis.
