Image Processing Reference
In-Depth Information
520
530
540
510
550
H
560
570
G
500
580
X
590
600
610
R
630
W
680
490
X´
H´
480
B
470
470
460
460
420
420
Fig. 2.4. The definition of hue and purity
luminosity are represented by the same point. The pure hue is defined via the normal-
ized color components
x, y
and is to be found at the boundaries, where the dominant
wavelength of photons producing this color is also read out. The point marked as
H
in the figure is a pure hue, whereas less pure colors of the same hue are to be found
on the line segment between
W
and
H
. The point
H
has the purity 1, while the point
marked as
X
has the purity
WX
WH
representing the distance from
W
to
X
. The point
X
is the
complementary color
of
X
, and is found in the opposite
direction, but with the same purity,
WX
WH
with
WX
=
WX
WH
. The point
H
is the boundary
point obtained by mirroring
H
through
W
.