Examples/DataRepresentation/Mesh/ImageToPointSet.cxx

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 *
 *  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.
 *
 *=========================================================================*/
 
//  Software Guide : BeginLatex
//
//  This example illustrates how to convert an ITK Image into a PointSet.
//
//  Software Guide : EndLatex
 
// Software Guide : BeginCodeSnippet
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
 
 
#include "itkImage.h"
#include "itkPointSet.h"
#include "itkImageRegionConstIterator.h"
 
 
int
main(int argc, char * argv[])
{
  // Verify the number of parameters in the command line
  if (argc < 2)
  {
    std::cerr << "Usage: " << std::endl;
    std::cerr << argv[0] << " inputImageFile  " << std::endl;
    return EXIT_FAILURE;
  }
 
 
  using PixelType = unsigned char;
  constexpr unsigned int Dimension = 2;
 
  using ImageType = itk::Image<PixelType, Dimension>;
  using PointSetType = itk::PointSet<PixelType, Dimension>;
  using ReaderType = itk::ImageFileReader<ImageType>;
 
  auto reader = ReaderType::New();
 
  const char * inputFilename = argv[1];
  reader->SetFileName(inputFilename);
 
  try
  {
    reader->Update();
  }
  catch (const itk::ExceptionObject & err)
  {
    std::cout << "ExceptionObject caught !" << std::endl;
    std::cout << err << std::endl;
    return EXIT_FAILURE;
  }
 
  auto pointSet = PointSetType::New();
 
 
  using IteratorType = itk::ImageRegionConstIterator<ImageType>;
 
  const ImageType * image = reader->GetOutput();
 
  IteratorType it(image, image->GetBufferedRegion());
 
  it.GoToBegin();
 
 
  using PointType = PointSetType::PointType;
  PointType point;
 
  unsigned long pointId = 0;
 
  while (!it.IsAtEnd())
  {
 
    // Convert the pixel position into a Point
    image->TransformIndexToPhysicalPoint(it.GetIndex(), point);
    pointSet->SetPoint(pointId, point);
 
    // Transfer the pixel data to the value associated with the point.
    pointSet->SetPointData(pointId, it.Get());
 
    ++it;
    ++pointId;
  }
 
 
  std::cout << "Number Of Points = ";
  std::cout << pointSet->GetNumberOfPoints() << std::endl;
 
 
  // Software Guide : EndCodeSnippet
  return EXIT_SUCCESS;
}