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<front>
<journal-meta>
<journal-id journal-id-type="publisher">ISPRS-Archives</journal-id>
<journal-title-group>
<journal-title>The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences</journal-title>
<abbrev-journal-title abbrev-type="publisher">ISPRS-Archives</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub">2194-9034</issn>
<publisher><publisher-name>ISPRS</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/isprsarchives-XXXIX-B7-137-2012</article-id>
<title-group>
<article-title>HYPERSPECTRAL DATA CLASSIFICATION USING FACTOR GRAPHS</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Makarau</surname>
<given-names>A.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Müller</surname>
<given-names>R.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Palubinskas</surname>
<given-names>G.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Reinartz</surname>
<given-names>P.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>German Aerospace Center (DLR) German Remote Sensing Data Center (DFD) bzw. Remote Sensing Technology Institute (IMF) 82234 Oberpfaffenhofen, Germany</addr-line>
</aff>
<pub-date pub-type="epub">
<day>31</day>
<month>07</month>
<year>2012</year>
</pub-date>
<volume>XXXIX-B7</volume>
<fpage>137</fpage>
<lpage>140</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2012 A. Makarau et al.</copyright-statement>
<copyright-year>2012</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/3.0/">https://creativecommons.org/licenses/by/3.0/</ext-link></license-p>
</license>
</permissions>
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<abstract>
<p>Accurate classification of hyperspectral data is still a competitive task and new classification methods are developed to achieve desired
tasks of hyperspectral data use. The objective of this paper is to develop a new method for hyperspectral data classification ensuring
the classification model properties like transferability, generalization, probabilistic interpretation, etc. While factor graphs (undirected
graphical models) are unfortunately not widely employed in remote sensing tasks, these models possess important properties such as
representation of complex systems to model estimation/decision making tasks.
&lt;br&gt;&lt;br&gt;
In this paper we present a new method for hyperspectral data classification using factor graphs. Factor graph (a bipartite graph consisting
of variables and factor vertices) allows factorization of a more complex function leading to definition of variables (employed to store
input data), latent variables (allow to bridge abstract class to data), and factors (defining prior probabilities for spectral features and
abstract classes; input data mapping to spectral features mixture and further bridging of the mixture to an abstract class). Latent
variables play an important role by defining two-level mapping of the input spectral features to a class. Configuration (learning) on
training data of the model allows calculating a parameter set for the model to bridge the input data to a class.
&lt;br&gt;&lt;br&gt;
The classification algorithm is as follows. Spectral bands are separately pre-processed (unsupervised clustering is used) to be defined
on a finite domain (alphabet) leading to a representation of the data on multinomial distribution. The represented hyperspectral data
is used as input evidence (evidence vector is selected pixelwise) in a configured factor graph and an inference is run resulting in the
posterior probability. Variational inference (Mean field) allows to obtain plausible results with a low calculation time. Calculating the
posterior probability for each class and comparison of the probabilities leads to classification. Since the factor graphs operate on input
data represented on an alphabet (the represented data transferred into multinomial distribution) the number of training samples can be
relatively low.
&lt;br&gt;&lt;br&gt;
Classification assessment on Salinas hyperspectral data benchmark allowed to obtain a competitive accuracy of classification. Employment
of training data consisting of 20 randomly selected points for a class allowed to obtain the overall classification accuracy equal
to 85.32% and Kappa equal to 0.8358. Representation of input data on a finite domain discards the curse of dimensionality problem
allowing to use large hyperspectral data with a moderately high number of bands.</p>
</abstract>
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