
Digital Topology: Fundamentals 21
(a) (b)
FIGURE 1.18: Thinned pattern o btained by ESPTA (a) original 3-D object,
and (b) thinned pattern.
1.4.2 Adjacency Tree
Let C = {C
0
, C
1
, . . . C
k
} be the set of k disjoint connected components
of foreground and background of a 2-D digital picture P = (G
2
, m, n, S). It
may be noted tha t foreground components are m-connected and the back-
ground c omponents are n-connected. We further denote F ⊂ C as the set
of foreground components and B ⊂ C as the set of background components.
Two components C
i
and C
j
form an edge, if there exist p ∈ C
i
and q ∈ C
j
such that they are adjacent. In this case, if C
i
is a foreground co ...