Merge pull request #486 from GabrieleBelotti/GabrieleBelotti-erratum-…

…Parker Corrected Parker weights references
RTKConsortium · Apr 26, 2022 · d5112fc · d5112fc
2 parents 26f7829 + 72238ee
commit d5112fc
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diff --git a/include/rtkParkerShortScanImageFilter.h b/include/rtkParkerShortScanImageFilter.h
@@ -29,12 +29,10 @@ namespace rtk
 
 /** \class ParkerShortScanImageFilter
  *
- * Weighting of image projections to handle off-centered panels
- * in tomography reconstruction. Based on [Wang, Med Phys, 2002].
- *
- * Note that the filter does nothing if the panel shift is less than 10%
- * of its size. Otherwise, it does the weighting described in the publication
- * and zero pads the data on the nearest side to the center.
+ * Weighting of image projections to handle short-scans
+ * in tomography reconstruction. Based on [Parker, Med Phys, 1982].
+ * Class implements a fix to typo in equation (12) of Parker as seen
+ * in book "Principles of computerized tomographic imaging" by Kak and Slaney
  *
  * \test rtkshortscantest.cxx, rtkshortscancompcudatest.cxx
  *

diff --git a/include/rtkParkerShortScanImageFilter.hxx b/include/rtkParkerShortScanImageFilter.hxx
@@ -193,6 +193,7 @@ ParkerShortScanImageFilter<TInputImage, TOutputImage>::DynamicThreadedGenerateDa
       else if (beta <= pi - 2 * alpha)
         itWeights.Set(2.);
       else if (beta <= pi + 2 * m_Delta)
+        // Denominator fix to a typo in equation (12) of Parker's article.
         itWeights.Set(2. * pow(sin((pi * (pi + 2 * m_Delta - beta)) / (4 * (m_Delta + alpha))), 2.));
       else
         itWeights.Set(0.);