ITK/Examples/Broken/Statistics/ImageToHistogramFilter

The iterator is not increasing over all of the components? The second two components of the cell centers do not move from 0? All of the frequencies are 0?

The current output is <source lang="text"> Index = [0, 2, 0] Histogram cell center = [66.9375, 0, 0] Frequency = 0 Index = [1, 2, 0] Histogram cell center = [200.812, 0, 0] Frequency = 0 Index = [0, 2, 0] Histogram cell center = [66.9375, 0, 0] Frequency = 0 Index = [1, 2, 0] Histogram cell center = [200.812, 0, 0] Frequency = 0 Index = [0, 2, 1] Histogram cell center = [66.9375, 0, 0] Frequency = 0 Index = [1, 2, 1] Histogram cell center = [200.812, 0, 0] Frequency = 0 Index = [0, 2, 1] Histogram cell center = [66.9375, 0, 0] Frequency = 0 Index = [1, 2, 1] Histogram cell center = [200.812, 0, 0] Frequency = 0 Frequency = 0

</source>

I would expect to see the index counting from (0,0,0) to (2,2,2), the Cell center following the same pattern as the index, and some of the frequencies to be non-zero.

ImageToHistogramFilter.cxx

<source lang="cpp">

1. include "itkImageToHistogramFilter.h"
2. include "itkImage.h"
3. include "itkRGBPixel.h"
4. include "itkImageRegionIteratorWithIndex.h"

1. include <fstream>

typedef itk::RGBPixel<unsigned char> RGBPixelType; typedef itk::Image< RGBPixelType, 2> RGBImageType;

void CreateImage(RGBImageType::Pointer image);

int main(int, char *[]) {

 const unsigned int MeasurementVectorSize = 3; // RGB

 RGBImageType::Pointer image = RGBImageType::New();
 CreateImage(image);

 typedef itk::Statistics::ImageToHistogramFilter< RGBImageType >         HistogramFilterType;
 typedef HistogramFilterType::HistogramMeasurementVectorType             HistogramMeasurementVectorType;
 typedef HistogramFilterType::HistogramSizeType                          HistogramSizeType;
 typedef HistogramFilterType::HistogramType                              HistogramType;

 HistogramFilterType::Pointer filter = HistogramFilterType::New();
 filter->SetInput(image);
 filter->SetAutoMinimumMaximum(true);

 HistogramSizeType histogramSize( MeasurementVectorSize );

 histogramSize[0] = 2;  // number of bins for the Red   channel
 histogramSize[1] = 2;  // number of bins for the Green channel
 histogramSize[2] = 2;  // number of bins for the Blue  channel

 filter->SetHistogramSize(histogramSize);
 filter->SetMarginalScale(10); // Required (could this be set in the filter?)
 filter->Update();

 const HistogramType * histogram = filter->GetOutput();

 HistogramType::ConstIterator histogramIterator = histogram->Begin();

 while( histogramIterator  != histogram->End() )
   {
   std::cout << "Index = " << histogram->GetIndex(histogramIterator.GetMeasurementVector())

<< " Histogram cell center = " << histogramIterator.GetMeasurementVector() << " Frequency = " << histogramIterator.GetFrequency() << std::endl;

   ++histogramIterator ;
   }

 HistogramType::MeasurementVectorType mv(3);
 mv[0] = 255;
 mv[1] = 0;
 mv[2] = 0;
 std::cout << "Frequency = " << histogram->GetFrequency(histogram->GetIndex(mv)) << std::endl;
 return EXIT_SUCCESS;

}

void CreateImage(RGBImageType::Pointer image) {

 // Create a black image with a red square and a green square.
 // This should produce a histogram with very strong spikes.
 RGBImageType::SizeType   size;
 size[0] = 3;
 size[1] = 3;

 RGBImageType::IndexType  start;
 start[0] = 0;
 start[1] = 0;

 RGBImageType::RegionType region;
 region.SetIndex(start);
 region.SetSize(size);

 image->SetRegions(region);
 image->Allocate();

 itk::ImageRegionIteratorWithIndex< RGBImageType > iterator( image, image->GetLargestPossibleRegion() );
 iterator.GoToBegin();

 RGBPixelType redPixel;
 redPixel.SetRed(255);
 redPixel.SetGreen(0);
 redPixel.SetBlue(0);

 RGBPixelType blackPixel;
 blackPixel.SetRed(0);
 blackPixel.SetGreen(0);
 blackPixel.SetBlue(0);

 itk::ImageRegionIterator<RGBImageType> imageIterator(image,region);

 while(!imageIterator.IsAtEnd())
   {
   imageIterator.Set(blackPixel);
   ++imageIterator;
   }

 RGBImageType::IndexType index;
 index[0] = 0; index[1] = 0;
 image->SetPixel(index, redPixel);

 index[0] = 1; index[1] = 0;
 image->SetPixel(index, redPixel);  

} </source>

CMakeLists.txt

<source lang="cmake"> cmake_minimum_required(VERSION 2.6)

PROJECT(ImageToHistogramFilter)

FIND_PACKAGE(ITK REQUIRED) INCLUDE(${ITK_USE_FILE})

ADD_EXECUTABLE(ImageToHistogramFilter ImageToHistogramFilter.cxx) TARGET_LINK_LIBRARIES(ImageToHistogramFilter ITKBasicFilters ITKCommon ITKIO ITKStatistics)

</source>