However, the major limitation of these classifiers relied on its
statistic assumptions which are not sufficiently model remote
sensing data (Waske and Benediksson, 2007). This nature cause
remarkable difficulties for parametric classifiers to incorporate
different kinds of data for classification. Unlike conventional
classifiers, the non-parametric classification algorithms such as
Artificial Neural Network (ANN) or Support Vector Machine
(SVM) are not constrained on the assumption of normal
distribution and are therefore considered more appropriate for
handling complex datasets.
1.3. Classifier combinations
One of the recent technical development for mapping land cover
features is classifier combination or Multiple Classifier System
(MCS). Each kind of classification algorithm has its own merits
and limitations. The classifier combination techniques can take
advantages of each classifier and improve the overall accuracy.
Application of multiple classifier system (MCS) in remote
sensing has been discussed in Benediksson et al. (2007). There
are many methods for combine classifier such as Majority
Voting, Weigh Sum, Bagging or Boosting. Du et al. (2009)
used different combination approach including parallel and
hierarchical classifier systems, training samples manipulation
with Bagging and Boosting techniques for classifying
hyperspectral data. Foody et al. (2007) integrated five classifiers
based on majority voting rule for mapping fenland East Anglia,
UK. Salah et al. (2010) employed the Fuzzy Majority Voting
techniques to combine classification results of three classifiers
over four different study areas using lidar and aerial images.
The other technique which has been applied successfully for
classifier’s combination is Dempster-Shafer (DS) theory (Du et
al. 2009, Trinder and Salah 2010).
Although both FS and the MCS techniques have been used
widely for classify remote sensing data this study is probably
the first effort to integrate these techniques for classifying multi-
source satellite imagery.
In this study, an approach, in which synergistic use of a FS
methods with Genetic Algorithm (GA) and multiple classifiers
combination based on Dempster-Shafer Theory of Evidence, is
proposed and evaluated for classifying land cover features in
New South Wales, Australia. We called this approach FS-GA-
DS model.
2. STUDY AREA AND USED DATA
The study area was located in Appin, New South Wales,
Australia, centred around the coordinate 150° 44° 30” E; 34°
12? 30" S. The site is characterised with diversity of covered
features such as native dense forest, grazing land, urban & rural
residential areas, facilities and water surfaces.
Remote sensing data used for this study includes:
Optical: Three Landsat 5 TM-- images acquired on 25/03/2010,
10/9/2010 and 31/12/2010 with 7 spectral bands and the spatial
resolution is 30m. In this study 6 spectral bands except the
thermal band were used.
Synthetic Aperture Radar (SAR): 6 ENVISAT/ASAR VV
polarization and 6 ALOS/PALSAR HH polarization images
acquired in 2010 (Table 1).
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
Satellite/Sensors Date | Polarization Mode
04/01/2010 HH Ascending
22/05/2010 HH Ascending
ALOS/PALSAR | 07/07/2010 HH Ascending
22/08/2010 HH Ascending
07/10/2010 HH Ascending
22/11/2010 HH Ascending
03/04/2010 VV Descending
24/06/2010 VV Ascending
ENVISAT/ASAR | 25/06/2010 VV Descending
27/06/2010 VV Ascending
28/06/2010 VV Descending
25/09/2010 VV Descending
Table 1. ENVISAT/ASAR and ALOS/PALSAR images for the
study area.
15042'E
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Figure 1. ENVISAT/ASAR VV polarized image acquired on
25/09/2010
150°40E 150°47E 150°44E 150°46'E 150"48'E 150°50°E
34°8'8
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Figure 2. ALOS/PALSAR HH polarized image acquired on
07/10/2010