SphinxExamples/src/Filtering/ImageStatistics/StatisticalPropertiesOfRegions/Code.cxx

/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkImageRegionIterator.h"
#include "itkBinaryImageToLabelMapFilter.h"
#include "itkLabelMapToLabelImageFilter.h"
#include "itkLabelStatisticsImageFilter.h"
 
using ImageType = itk::Image<unsigned char, 2>;
static void
CreateImage(ImageType::Pointer image);
 
int
main()
{
  auto image = ImageType::New();
  CreateImage(image);
 
  using BinaryImageToLabelMapFilterType = itk::BinaryImageToLabelMapFilter<ImageType>;
  auto binaryImageToLabelMapFilter = BinaryImageToLabelMapFilterType::New();
  binaryImageToLabelMapFilter->SetInput(image);
  binaryImageToLabelMapFilter->Update();
 
  using LabelMapToLabelImageFilterType =
    itk::LabelMapToLabelImageFilter<BinaryImageToLabelMapFilterType::OutputImageType, ImageType>;
  auto labelMapToLabelImageFilter = LabelMapToLabelImageFilterType::New();
  labelMapToLabelImageFilter->SetInput(binaryImageToLabelMapFilter->GetOutput());
  labelMapToLabelImageFilter->Update();
 
  using LabelStatisticsImageFilterType = itk::LabelStatisticsImageFilter<ImageType, ImageType>;
  auto labelStatisticsImageFilter = LabelStatisticsImageFilterType::New();
  labelStatisticsImageFilter->SetLabelInput(labelMapToLabelImageFilter->GetOutput());
  labelStatisticsImageFilter->SetInput(image);
  labelStatisticsImageFilter->Update();
 
  std::cout << "Number of labels: " << labelStatisticsImageFilter->GetNumberOfLabels() << std::endl;
  std::cout << std::endl;
 
  using LabelPixelType = LabelStatisticsImageFilterType::LabelPixelType;
 
  for (auto vIt = labelStatisticsImageFilter->GetValidLabelValues().begin();
       vIt != labelStatisticsImageFilter->GetValidLabelValues().end();
       ++vIt)
  {
    if (labelStatisticsImageFilter->HasLabel(*vIt))
    {
      LabelPixelType labelValue = *vIt;
      std::cout << "min: " << labelStatisticsImageFilter->GetMinimum(labelValue) << std::endl;
      std::cout << "max: " << labelStatisticsImageFilter->GetMaximum(labelValue) << std::endl;
      std::cout << "median: " << labelStatisticsImageFilter->GetMedian(labelValue) << std::endl;
      std::cout << "mean: " << labelStatisticsImageFilter->GetMean(labelValue) << std::endl;
      std::cout << "sigma: " << labelStatisticsImageFilter->GetSigma(labelValue) << std::endl;
      std::cout << "variance: " << labelStatisticsImageFilter->GetVariance(labelValue) << std::endl;
      std::cout << "sum: " << labelStatisticsImageFilter->GetSum(labelValue) << std::endl;
      std::cout << "count: " << labelStatisticsImageFilter->GetCount(labelValue) << std::endl;
      // std::cout << "box: " << labelStatisticsImageFilter->GetBoundingBox( labelValue ) << std::endl; // can't output
      // a box
      std::cout << "region: " << labelStatisticsImageFilter->GetRegion(labelValue) << std::endl;
      std::cout << std::endl << std::endl;
    }
  }
 
  return EXIT_SUCCESS;
}
 
void
CreateImage(ImageType::Pointer image)
{
  // Create a black image with a white square
  ImageType::IndexType start{};
 
  auto size = ImageType::SizeType::Filled(20);
 
  ImageType::RegionType region;
  region.SetSize(size);
  region.SetIndex(start);
  image->SetRegions(region);
  image->Allocate();
 
  itk::ImageRegionIterator<ImageType> imageIterator(image, image->GetLargestPossibleRegion());
 
  // Make a square
  while (!imageIterator.IsAtEnd())
  {
    if ((imageIterator.GetIndex()[0] > 5 && imageIterator.GetIndex()[0] < 10) &&
        (imageIterator.GetIndex()[1] > 5 && imageIterator.GetIndex()[1] < 10))
    {
      imageIterator.Set(255);
    }
    else
    {
      imageIterator.Set(0);
    }
 
    ++imageIterator;
  }
 
  itk::WriteImage(image, "image.png");
}