Retinal Image Matching Using Hierarchical Vascular Features

Table 1

The invariant features for vessel segments in the nodes of a tree model.

Nodes	Invariant features
	L/W	Bi/Br	Crossover	Cross pos.	Acute angle
1	88.77	1	0	0	0.877
2	18.27	0	0	0	1.126
3	43.12	0	0	0	0
4	34.27	1	1	0.79	0.788
5	53.42	1	0	0	0.689