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<front>
<journal-meta>
<journal-id journal-id-type="publisher">ISPRS-Archives</journal-id>
<journal-title-group>
<journal-title>ISPRS - 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>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/isprs-archives-XLII-2-W15-465-2019</article-id>
<title-group>
<article-title>SPARSE POINT CLOUD FILTERING BASED ON COVARIANCE FEATURES</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Farella</surname>
<given-names>E. M.</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>Torresani</surname>
<given-names>A.</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Remondino</surname>
<given-names>F.</given-names>

</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<ext-link>https://orcid.org/0000-0001-6097-5342</ext-link></contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>3D Optical Metrology (3DOM) unit, Bruno Kessler Foundation (FBK), Trento, Italy</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>University of Trento, Italy</addr-line>
</aff>
<pub-date pub-type="epub">
<day>22</day>
<month>08</month>
<year>2019</year>
</pub-date>
<volume>XLII-2/W15</volume>
<fpage>465</fpage>
<lpage>472</lpage>
<permissions>
<copyright-statement>Copyright: © 2019 E. M. Farella et al.</copyright-statement>
<copyright-year>2019</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri" xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://isprs-archives.copernicus.org/articles/isprs-archives-XLII-2-W15-465-2019.html">This article is available from https://isprs-archives.copernicus.org/articles/isprs-archives-XLII-2-W15-465-2019.html</self-uri>
<self-uri xlink:href="https://isprs-archives.copernicus.org/articles/isprs-archives-XLII-2-W15-465-2019.pdf">The full text article is available as a PDF file from https://isprs-archives.copernicus.org/articles/isprs-archives-XLII-2-W15-465-2019.pdf</self-uri>
<abstract>
<p>&lt;p&gt;This work presents an extended photogrammetric pipeline aimed to improve 3D reconstruction results. Standard photogrammetric
pipelines can produce noisy 3D data, especially when images are acquired with various sensors featuring different properties. In this
paper, we propose an automatic filtering procedure based on some geometric features computed on the sparse point cloud created
within the bundle adjustment phase. Bad 3D tie points and outliers are detected and removed, relying on micro and macro-clusters
analyses. Clusters are built according to the prevalent dimensionality class (1D, 2D, 3D) assigned to low-entropy points, and
corresponding to the main linear, planar o scatter local behaviour of the point cloud. While the macro-clusters analysis removes smallsized
clusters and high-entropy points, in the micro-clusters investigation covariance features are used to verify the inner coherence of
each point to the assigned class. Results on heritage scenarios are presented and discussed.&lt;/p&gt;</p>
</abstract>
<counts><page-count count="8"/></counts>
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