SphinxExamples/src/Filtering/ImageIntensity/ComputeEdgePotential/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 "itkCovariantVector.h"
#include "itkEdgePotentialImageFilter.h"
#include "itkGradientImageFilter.h"
#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkRescaleIntensityImageFilter.h"
 
using UnsignedCharImageType = itk::Image<unsigned char, 2>;
 
static void
CreateImage(UnsignedCharImageType::Pointer image);
 
int
main(int /*argc*/, char * /*argv*/[])
{
  // Setup types
  using FloatImageType = itk::Image<float, 2>;
  using VectorImageType = itk::Image<itk::CovariantVector<float, 2>, 2>;
 
  auto image = UnsignedCharImageType::New();
  CreateImage(image);
 
  // Create and setup a gradient filter
  using GradientFilterType = itk::GradientImageFilter<UnsignedCharImageType, float>;
  auto gradientFilter = GradientFilterType::New();
  gradientFilter->SetInput(image);
  gradientFilter->Update();
 
  // Create and setup an edge potential filter
  using EdgePotentialImageFilterType = itk::EdgePotentialImageFilter<VectorImageType, FloatImageType>;
  auto edgePotentialImageFilter = EdgePotentialImageFilterType::New();
  edgePotentialImageFilter->SetInput(gradientFilter->GetOutput());
  edgePotentialImageFilter->Update();
 
  // Scale so we can write to a PNG
  using RescaleFilterType = itk::RescaleIntensityImageFilter<FloatImageType, UnsignedCharImageType>;
  auto rescaleFilter = RescaleFilterType::New();
  rescaleFilter->SetInput(edgePotentialImageFilter->GetOutput());
  rescaleFilter->SetOutputMinimum(0);
  rescaleFilter->SetOutputMaximum(255);
  rescaleFilter->Update();
 
  itk::WriteImage(rescaleFilter->GetOutput(), "output.png");
 
  return EXIT_SUCCESS;
}
 
 
void
CreateImage(UnsignedCharImageType::Pointer image)
{
  // Create a black image with 2 white regions
 
  UnsignedCharImageType::IndexType start;
  start.Fill(0);
 
  UnsignedCharImageType::SizeType size;
  size.Fill(200);
 
  UnsignedCharImageType::RegionType region(start, size);
  image->SetRegions(region);
  image->Allocate();
  image->FillBuffer(0);
 
  // Make a square
  for (unsigned int r = 20; r < 80; ++r)
  {
    for (unsigned int c = 30; c < 100; ++c)
    {
      UnsignedCharImageType::IndexType pixelIndex;
      pixelIndex[0] = r;
      pixelIndex[1] = c;
 
      image->SetPixel(pixelIndex, 255);
    }
  }
}