ENH: Use BinaryFunctor for "digitializing" input image

Use a threaded filter to perform digitizing and masking of the input
image into histograms bins. Reuse the Digitizer functor.

Author: blowekamp

include/itkRunLengthTextureFeaturesImageFilter.h

@@ -113,6 +113,8 @@ class ITK_TEMPLATE_EXPORT RunLengthTextureFeaturesImageFilter:public ImageToImag
 
   typedef TInputImage                     InputImageType;
   typedef TOutputImage                    OutputImageType;
+  typedef TInputImage                     MaskImageType;
+  typedef TInputImage                     DigitizedImageType;
 
   typedef typename InputImageType::PixelType    PixelType;
   typedef typename InputImageType::IndexType    IndexType;

include/itkRunLengthTextureFeaturesImageFilter.hxx

@@ -21,6 +21,8 @@
 #include "itkRunLengthTextureFeaturesImageFilter.h"
 #include "itkRegionOfInterestImageFilter.h"
 #include "itkNeighborhoodAlgorithm.h"
+#include "itkBinaryFunctorImageFilter.h"
+#include "itkDigitizerFunctor.h"
 
 namespace itk
 {
@@ -84,46 +86,37 @@ void
 RunLengthTextureFeaturesImageFilter<TInputImage, TOutputImage>
 ::BeforeThreadedGenerateData()
 {
-  typename TInputImage::Pointer maskPointer = TInputImage::New();
-  maskPointer = const_cast<TInputImage *>(this->GetMaskImage());
-  this->m_DigitizedInputImage = InputImageType::New();
-  this->m_DigitizedInputImage->SetRegions(this->GetInput()->GetRequestedRegion());
-  this->m_DigitizedInputImage->CopyInformation(this->GetInput());
-  this->m_DigitizedInputImage->Allocate();
-  typedef itk::ImageRegionIterator< InputImageType> IteratorType;
-  IteratorType digitIt( this->m_DigitizedInputImage, this->m_DigitizedInputImage->GetLargestPossibleRegion() );
-  typedef itk::ImageRegionConstIterator< InputImageType> ConstIteratorType;
-  ConstIteratorType inputIt( this->GetInput(), this->GetInput()->GetLargestPossibleRegion() );
-  unsigned int binNumber;
-  while( !inputIt.IsAtEnd() )
+
+  typename TInputImage::Pointer input = InputImageType::New();
+  input->Graft(const_cast<TInputImage *>(this->GetInput()));
+
+  typedef Digitizer<PixelType,
+                      PixelType,
+                      typename DigitizedImageType::PixelType>
+    DigitizerFunctorType;
+
+  DigitizerFunctorType digitalizer(m_NumberOfBinsPerAxis, m_InsidePixelValue, m_HistogramValueMinimum, m_HistogramValueMaximum);
+
+  typedef BinaryFunctorImageFilter< MaskImageType, InputImageType, InputImageType, DigitizerFunctorType> FilterType;
+  typename FilterType::Pointer filter = FilterType::New();
+  if (this->GetMaskImage() != ITK_NULLPTR)
     {
-    if( maskPointer && maskPointer->GetPixel( inputIt.GetIndex() ) != this->m_InsidePixelValue )
-      {
-      digitIt.Set(-10);
-      }
-    else if(inputIt.Get() < this->m_HistogramValueMinimum || inputIt.Get() >= this->m_HistogramValueMinimum)
-      {
-      digitIt.Set(-1);
-      }
-    else
-      {
-      binNumber = ( inputIt.Get() - m_HistogramValueMinimum)/( (m_HistogramValueMaximum - m_HistogramValueMinimum) / (float)m_NumberOfBinsPerAxis );
-      digitIt.Set(binNumber);
-      }
-    ++inputIt;
-    ++digitIt;
+    typename TInputImage::Pointer mask = MaskImageType::New();
+    mask->Graft(const_cast<TInputImage *>(this->GetMaskImage()));
+    filter->SetInput1(mask);
     }
-  m_Spacing = this->GetInput()->GetSpacing();
+  else
+    {
+    filter->SetConstant1(m_InsidePixelValue);
+    }
+  filter->SetInput2(input);
+  filter->SetFunctor(digitalizer);
+  filter->SetNumberOfThreads(this->GetNumberOfThreads());
 
-  // Support VectorImages by setting the number of components on the output.
-  typename TOutputImage::Pointer outputPtr = TOutputImage::New();
-  outputPtr = this->GetOutput();
-  if ( strcmp(outputPtr->GetNameOfClass(), "VectorImage") == 0 )
-      {
-      typedef typename TOutputImage::AccessorFunctorType AccessorFunctorType;
-      AccessorFunctorType::SetVectorLength( outputPtr, 10 );
-      }
-  outputPtr->Allocate();
+  filter->Update();
+  m_DigitizedInputImage = filter->GetOutput();
+
+  m_Spacing = this->GetInput()->GetSpacing();
 }