Merge pull request #1767 from ANTsX/AtroposDegCase

BUG:  Address degenerate case.

ImageSegmentation/antsAtroposSegmentationImageFilter.hxx

@@ -41,6 +41,7 @@
 #include "itkOtsuMultipleThresholdsCalculator.h"
 #include "itkSampleClassifierFilter.h"
 #include "itkSignedMaurerDistanceMapImageFilter.h"
+#include "itkStatisticsImageFilter.h"
 #include "itkVariableSizeMatrix.h"
 #include "itkVectorIndexSelectionCastImageFilter.h"
 #include "itkWeightedCentroidKdTreeGenerator.h"
@@ -1306,6 +1307,18 @@ AtroposSegmentationImageFilter<TInputImage, TMaskImage, TClassifiedImage>::Updat
  NumericTraits<RealType>::OneValue() / static_cast<RealType>(totalNumberOfClasses);
  }
  }
+ // Check to see if the resulting number of classes is equal to the total number of classes.
+ using StatisticsImageFilterType = itk::StatisticsImageFilter<ClassifiedImageType>;
+ auto statisticsImageFilter = StatisticsImageFilterType::New();
+ statisticsImageFilter->SetInput(maxLabels);
+ statisticsImageFilter->Update();
+
+ if (statisticsImageFilter->GetMaximum() != totalNumberOfClasses)
+ {
+ itkExceptionMacro("Updating the class labeling resulted in " << statisticsImageFilter->GetMaximum() <<
+ " non-zero label sets but " << totalNumberOfClasses << " is requested.");
+ }
+
  auto labelMapFilter = itk::LabelImageToShapeLabelMapFilter<ClassifiedImageType>::New();
  labelMapFilter->SetInput(maxLabels);
  labelMapFilter->SetComputeOrientedBoundingBox(false);