1e 
a- 
at 
a-— 
In fig.1 bank structures on the surface of à tidal flat area 
are shown, The image shows a part of the tidal flats near 
Hooksiel about 20 km northern Wilhelmshaven, Germany. Between 
the banks there are depressions filled with water. These are 
only a few cm deep. The distributions of the reflexion values 
for the banks and the depressions, measured on the earth surface 
do not overlap at that hour of the day when the aerial photo- 
graph of fig. was taken. 
This difference of reflection on the ground between banks and 
depressions causes different greytone for the images of the banks 
and the depressions on the IR-photograph. 9o it is possible to 
Separate banks and depressions by image preprocessing. 
So two types of elementary objects have to be distinguished, 
the images of the banks and the images of the depressions, 
which are complementary to each other, 
Fig. 2 shows the amount of area of the banks and of both, banks and 
depressions as measured from the image, The largest bank on ground has a 
length of 20 m and a width between 6 and 10 m so that must have 
a size of 6m x On x scale, This is a size of 5x5 pixel. 
If the significance factor is set to 1, the perception value must 
be 2/4, If the perception value would be smaller, the image struc- 
ture would not be a texture in the whole image section. If the 
image structure is not texture in the whole image section, if the 
perception value is 2/4, then one might conclude that there is 
a disturbance in the process of bank development, 
Fig. ^ shows a part of the investigated image section. The image 
was filtered before. In the image section shown in fig. 3 there 
are no disturbances in the process of bank development. 
This example shows that the choice of the perception value may 
depend from measurements on the ground. For its computation in 
this example mean and standard deviation of the common distribu- 
tion of the amount of the areas of banks and depressions was 
used, The small perception value shows a good homogeneity of texture. 
If the image structure showing the banks and the depressions from 
the surface of the tidal flat area is not texture, when the per- 
ception value is equal 2/4 then there is a greater depression 
between the banks or a greater bank between the depressions, so 
the pattern of the banks respectively the pattern of the depres- 
‘sions is disturbed. So the perception value can be used as an 
arrangement parameter for one of the both types of elementary 
object images. 
6. Conclusion 
For analysing textures three groups of parameters are important: 
1. greytone variance parameters (as defined by Haralick) 
2. shape parameters 
5. arrange parameters 
By greytone variance parameters a texture is not characterized 
sufficiently. A correlation between parameters and properties 
of objects on the earth surface is not possible. 
The definition of texture is possible by using shape parameters 
and arrangement parameters, These parameters correlate with pro-