
52 Digital Geometry in Image Processing
Theorem 2.11. d
Knight
is a metric over Z
2
.
Theorem 2.12. ∀u, v ∈ Z
2
, d
Knight
(u, v) is the length of a shortest Knight’s
path from u to v as defined by N(Knight).
Proof. Adopt Algorithm 2 for N (Knight) and proceed as in d
n
m
.
The Knight’s move is non-proximal and somewhat atypical in digital geom-
etry. Yet, it has been extended in [72] as a Super-Knight’ s Distance with a
class of neighborhood sets N(Super −Knight) = {(±p, ±q), (±p, ±q)} where
p, q ∈ P and p ≥ q ≥ 1. d
Super−Knight
is a metric under ce rtain conditions
(see Ex ercise 3) on N(Super − Knight) [72].
2.4 Path-Dependent Neighborhoods and Distances
In the ...