Geography Reference
In-Depth Information
following a rule of connexion, the neighbouring pixels which are involved in the evaluation
of the parameter of texture. After that, the necessary operations are made on these pixels.
3.2.1. Generic tree
The generic tree for the computation of the textural parameters (figure 1) has for seed a
pixel positioned in some coordinates
,
of the image, with the condition
∈0,
and
∈
0,
, where
and
designate the number of lines and the number of
columns of the image, respectively. The different conditions specify the borders of
variation of
and
.
From the pixel positioned in coordinates
,
of the image window one can reach the pixel
positioned in
,,
(respectively in
,,
) by respecting the rule of connexion
,
(respectively
,
+180°
), if the condition
(respectively the condition
)
is verified. From the pixel positioned in
,,
(respectively in
,,
) one can reach
the pixel positioned in
,,
,
,
(respectively in
,,
,
,
+180°
)
by respecting the rule of connexion
,
(respectively
,
+180°
), if the
condition
(respectively the condition
) is verified. Let us call back that a rule of
connexion
,
means that one considers an inter-pixel distance of
and an angle of
(and
+180°
) degrees for the evaluation of the textural parameters. At the order three,
one obtains the seven pixels
,,,,,,
, presented on the equation 3:
=
,
=
,
,
=
,
,
=
,
,
+180°
=
,
,
+180°
=
,
,
=
,
,
+180°
(3)
In the equation 3:
is the current pixel, identified by its coordinates
,
in the image;
,
,
is the neighbouring pixel of
respecting the rule of connexion
,
;
,
,
is the neighbouring pixel of
respecting the rule of connexion
,
;
,
,
+180°
is the neighbouring pixel of
respecting the rule of connexion
,
+180°
;
,
,
+180°
is the neighbouring pixel of
respecting the rule of connexion
,
+
180°
;
,
,
is the neighbouring pixel of
respecting the rule of connexion
,
;
,
,
+180°
is the neighbouring pixel of
respecting the rule of connexion
,
+180°
.
