Contribution of SAR Radar Images for the Cartography: Case of Mangrove and Post Eruptive Regions - Cartography: A Tool for Spatial Analysis - page 208

present the generic tree for the calculation of textural parameters of order three, for various
rules of connexion. The conditions ⋯ are detailed on each of these figures.
 , is a position of pixel in the image window;
 is a distance between pixels;
 is a width of window image;
 is a height of window image.

Figure 3. Exploration of the generic tree for the calculation of textural parameters of order three. E : rule
of connexion R1 (d1, d2, 0°, 0°) ; F : rule of connexion R2 (d1, d2, 0°, 45°).

3.2.2. Formulation of the textural parameters of order n>1 from the generic tree

On table 1, the expressions of some textural parameters are presented. They are expressed
by the approach of generic tree at the order n >1. The corresponding classical formulations
are also presented there.

3.2.3. Evaluation of textural parameters from the generic tree

We interest, for example, in the evaluation of the textural parameter «asymmetry» in the
order two, in some pixels of an image. The classical formulation of this parameter expresses
itself by the equation 4:

2= ∑∑| − | × ,

(4)

In this equation, is the maximal level of gray in the image window and , is the
occurrence frequency of the pair of levels of gray , in the image, respecting the rule of
connexion , . This parameter can still express itself by the equation 5 :

2=∑ ∑|−|+|−|+⋯+|−|

(5)

,

The approach using generic tree in this study contains the following stages: