STYLE: Address Greptile review on TextureFeatures

itkFirstOrderTextureHistogram.h: guard the unbiased-variance estimate
on count > 1 so a single-pixel window no longer divides by zero and
produces NaN skewness; correct the stale \ingroup tag.

itkFirstOrderTextureFeaturesImageFilter.h: correct the stale
\ingroup tag from ITKTextureFeatures (old remote-module name) to
TextureFeatures.

itkCoocurrenceTextureFeaturesImageFilter.h: drop the unrelated
itkScalarImageToRunLengthMatrixFilter.h include — neither the .h
nor .hxx uses any type from it.

itkCoocurrenceTextureFeaturesImageFilter.hxx: write a zero output
pixel on the totalNumberOfFreq == 0 branch so the output never
contains uninitialized memory; replace raw new[]/delete[] of the
marginal-sums buffer with std::vector for exception safety and
zero-initialization.

test/CMakeLists.txt: drop the dead first set(TextureFeaturesTests …)
block — it listed nonexistent ScalarImageTo* sources and was
immediately overwritten by the second definition.

Author: hjmjohnson

Modules/Filtering/TextureFeatures/include/itkCoocurrenceTextureFeaturesImageFilter.h

@@ -19,7 +19,6 @@
 #define itkCoocurrenceTextureFeaturesImageFilter_h
 
 #include "itkImageToImageFilter.h"
-#include "itkScalarImageToRunLengthMatrixFilter.h"
 #include "itkConstNeighborhoodIterator.h"
 
 namespace itk

Modules/Filtering/TextureFeatures/include/itkCoocurrenceTextureFeaturesImageFilter.hxx

@@ -24,6 +24,8 @@
 #include "itkBinaryFunctorImageFilter.h"
 #include "itkDigitizerFunctor.h"
 
+#include <vector>
+
 namespace itk
 {
 namespace Statistics
@@ -229,6 +231,11 @@ CoocurrenceTextureFeaturesImageFilter<TInputImage, TOutputImage, TMaskImage>::Dy
         this->ComputeFeatures(hist, totalNumberOfFreq, outputPixel);
         outputIt.Set(outputPixel);
       }
+      else
+      {
+        outputPixel.Fill(0);
+        outputIt.Set(outputPixel);
+      }
 
       ++inputNIt;
       ++outputIt;
@@ -360,12 +367,8 @@ CoocurrenceTextureFeaturesImageFilter<TInputImage, TOutputImage, TMaskImage>::Co
   // cleverly compressed to one pass, but it's not clear that that's necessary.
 
   // Initialize everything
-  auto * marginalSums = new double[m_NumberOfBinsPerAxis];
+  std::vector<double> marginalSums(m_NumberOfBinsPerAxis, 0.0);
 
-  for (double * ms_It = marginalSums; ms_It < marginalSums + m_NumberOfBinsPerAxis; ms_It++)
-  {
-    *ms_It = 0;
-  }
   pixelMean = 0;
 
   // Ok, now do the first pass through the histogram to get the marginal sums
@@ -417,8 +420,6 @@ CoocurrenceTextureFeaturesImageFilter<TInputImage, TOutputImage, TMaskImage>::Co
       pixelVariance += (a - pixelMean) * (a - pixelMean) * (frequency);
     }
   }
-
-  delete[] marginalSums;
 }
 
 template <typename TInputImage, typename TOutputImage, typename TMaskImage>

Modules/Filtering/TextureFeatures/include/itkFirstOrderTextureFeaturesImageFilter.h

@@ -45,7 +45,7 @@ namespace itk
  * so that the boundary pixel have lets data to compute the
  * statistics.
  *
- * \ingroup ITKTextureFeatures
+ * \ingroup TextureFeatures
  */
 
 template <class TInputImage, class TOutputImage, class TKernel>

Modules/Filtering/TextureFeatures/include/itkFirstOrderTextureHistogram.h

@@ -34,7 +34,7 @@ namespace Function
  * std::map based "histogram" during iteration and computes first
  * order statistics from the histogram.
  *
- * \ingroup ITKTextureFeatures
+ * \ingroup TextureFeatures
  */
 template <class TInputPixel, class TOutputPixel>
 class ITK_TEMPLATE_EXPORT FirstOrderTextureHistogram
@@ -96,8 +96,8 @@ class ITK_TEMPLATE_EXPORT FirstOrderTextureHistogram
 
     const double mean = sum / count;
 
-    // unbiased estimate
-    const double variance = (sum2 - (sum * sum) / count) / (count - 1);
+    // unbiased estimate (requires at least 2 samples)
+    const double variance = (count > 1) ? (sum2 - (sum * sum) / count) / (count - 1) : 0.0;
     const double sigma = std::sqrt(variance);
     double       skewness = 0.0;
     double       kurtosis = 0.0;

Modules/Filtering/TextureFeatures/test/CMakeLists.txt

@@ -1,20 +1,5 @@
 itk_module_test()
 
-set(
-  TextureFeaturesTests
-  ScalarImageToRunLengthFeaturesImageFilterInstantiationTest.cxx
-  ScalarImageToRunLengthFeaturesImageFilterTest.cxx
-  ScalarImageToRunLengthFeaturesImageFilterTestSeparateFeatures.cxx
-  ScalarImageToRunLengthFeaturesImageFilterTestWithoutMask.cxx
-  ScalarImageToRunLengthFeaturesImageFilterTestWithVectorImage.cxx
-  ScalarImageToRunLengthFeaturesImageFilterTestVectorImageSeparateFeatures.cxx
-  ScalarImageToTextureFeaturesImageFilterInstantiationTest.cxx
-  ScalarImageToTextureFeaturesImageFilterTest.cxx
-  ScalarImageToTextureFeaturesImageFilterTestSeparateFeatures.cxx
-  ScalarImageToTextureFeaturesImageFilterTestWithoutMask.cxx
-  ScalarImageToTextureFeaturesImageFilterTestWithVectorImage.cxx
-)
-
 set(
   TextureFeaturesTests
   RunLengthTextureFeaturesImageFilterInstantiationTest.cxx