WikiExamples/Statistics/SampleToHistogramFilter.cxx

#include "itkSampleToHistogramFilter.h"
#include "itkListSample.h"
#include "itkHistogram.h"

using MeasurementVectorType = itk::Vector<unsigned char, 1>;
using SampleType = itk::Statistics::ListSample< MeasurementVectorType >;

using HistogramType = itk::Statistics::Histogram< float,
        itk::Statistics::DenseFrequencyContainer2 >;

void CreateSample(SampleType::Pointer image);

int main(int, char *[])
{
  SampleType::Pointer sample = SampleType::New();
  CreateSample(sample);

  using SampleToHistogramFilterType = itk::Statistics::SampleToHistogramFilter<SampleType, HistogramType>;
  SampleToHistogramFilterType::Pointer sampleToHistogramFilter =
    SampleToHistogramFilterType::New();
  sampleToHistogramFilter->SetInput(sample);

  SampleToHistogramFilterType::HistogramSizeType histogramSize(1);
  histogramSize.Fill(10);
  sampleToHistogramFilter->SetHistogramSize(histogramSize);

  sampleToHistogramFilter->Update();

  const HistogramType* histogram = sampleToHistogramFilter->GetOutput();
  std::cout << "Histogram vector size: " << histogram->GetMeasurementVectorSize() << std::endl;
  

  for(unsigned int i = 0; i < histogram->GetSize()[0]; i++)
    {
    std::cout << "Frequency of " << i << " : (" << histogram->GetBinMin(0, i) << " to " << histogram->GetBinMax(0, i) << ") = " << histogram->GetFrequency(i) << std::endl;
    }

  std::cout << "Total count " << histogram->GetTotalFrequency() << std::endl;

  return EXIT_SUCCESS;
}

void CreateSample(SampleType::Pointer sample)
{
  MeasurementVectorType mv;
  mv[0] = 1.0;
  sample->PushBack(mv);

  mv[0] = 1.0;
  sample->PushBack(mv);

  mv[0] = 2.0;
  sample->PushBack(mv);

}