International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B3. Istanbul 2004
2.3.2 Designing for the basic assignment function: Designing
for the basic assignment function m,(/) is: first, we set up a
model base of texture image by selecting a variety of texture
training samples according to prior knowledge; then we extract
features f; (i=1,2) from unknown texture, and match them with
features of image texture in model base respectively to obtain
correlation coefficients Pj), here / represents the class number
of texture in the model base; finally m£j) which feature f;
assigns texture j can be constructed by Pj) . Its expression
[Yang Jingyu, Wu Yongge, Liu Leijian Etc. 1994] is given as
follow:
yn Sls
m am Xen d
J
Where
a; = maxP;(j) is the maximum correlation coefficient
J
between feature /; of unknown texture and that of texture j
Toh i D St fficient of feature f,
B, X^ is distributing coefficient of feature f;
/
Vi = SI is reliable coefficient of feature /;..
Therefore
nz ANUS... (13)
Y p, Gn(0o.- y; X1-a;B;)
J
Here m; (6) is an uncertainty probability which feature f,
assigns frame of discernment 6.
According to Eq. (12), we can compute the single feature
(fractal dimension or entropy) probability mass function,
then fuse according to Eq.(11) probability mass functions of
2.3.3 Decision rules for texture classification: Based on the
analysis of the combined probability mass function, we adopt
four decision rules to classify textures:
*The target should have the largest probability mass function;
*The difference between the target probability mass function
and any other target's should be greater than threshold 4,
namely that the supporting degrees of all textures by each
possible proposition should have difference enough.
*The uncertainty probability m6) must be smaller than
threshold /2.
*The target probability mass function must be greater than
m0). When We seldom know a target, the classification can't
be preceded.
Above all, the processes of image texture classification based
on the Dempster— Shafer reasoning theory are given as follows:
First of all, m{A),Belief{A), and Plausibility(A) of each feature
are computed; Secondly, according to the combining rule,
compute the fused probability mass function m; and its Belief;
and Plausibility;, Finally, according to decision rules to choose
the maximum hypotheses in the action of fusion.
3. EXPERIMENT AND DISCUSSION
The performance of the method is investigated with some aerial
photos on some area. A Four-class texture classification is
considered, with the following classes: inhabitant area, water
field, woodland and grassland. 10 test samples from each
texture are obtained; the size of the test sample is 100 by 100
pixels. As a reference for evaluating the performance of multi-
feature fusion technique based on Dempster-Shafer's evidential
reasoning, the same decision rules (/,70.1,/570.3) are utilized,
classification accuracies with the single-feature (fractal
dimension or entropy of co-occurrence matrix) and the fused
feature are calculated. See Table 1. Compared with the results
obtained from the single feature, the results obtained from
multi-feature fusion have higher accuracy of classification,
single feature, either the fractal dimension or entropy of gray
co-occurrence matrix, is not sufficient for descripting texture.
This indicates the multi-feature fusion technique based on
Dempster-Shafer's evidential reasoning for classification is
all features to get the combined probability mass function. stable and
reliable, and efficiently improves the accuracy of image texture
classification.
Feature Fracta Entropy of grey Multi-
I co-occurrence feature
featur matrix fused
e
Accuracy of | 72.5% 80% 95%
classification
Table 1. The accuracy of texture classification based on Dempster-Shafer evidential reasoning.
664
Intern
Table
probat
feature
corres]
feature
corres]
Demps
to ide
probab
enhanc
A new
Shafer'
is presc
steps. /
is inves
with th
obtaine
fusion
reasonis
improve
Gallow:
run len
pp172-1
Haralic
texture.
Huang
fractal
e
Survey
Huang (
in imag
No.1, pp
Li Derer
texture a