14.11.2 Grayscale Morphology
Grayscale images can be denoted as functions, f, whose domain D is a subset of
the Euclidean grid Z
3
[58]
f vðÞ, v ¼ x, y, zðÞ2D Z
3
(14:56)
The structuring element can also be denoted as a function g within domain G
[58]
g vðÞ, v ¼ x , y, zðÞ2G Z
3
and the symmetric of g is
g
s
vðÞ¼g vðÞ
(14:57)
The operations of dilation, erosion, opening, and closing are then defined as
follows [58]
dilation: f
!
g
s
½vðÞ¼ max
v2D,vd2G
f vðÞþg v dðÞ
fg
erosion: f
@
g
s
½vðÞ¼ min
v2D,vd2G
f vðÞg v dðÞ
fg
opening: f
@
g
s
ðÞ
!
g
½
v
ðÞ
closing: f
!
g
s
ðÞ
@
g½vðÞ
(14:58)
where d is a vector that defines the translation. Grayscale opening suppresses
positive impulses but enhances negative ones, whereas closing does the con-
verse. Additionally, opening and closing