Regional Minimal

Synopsis

Regional minimal image filter.

Results

input.png

input.png

output.png

output.png

Code

C++

#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkRegionalMinimaImageFilter.h"

using ImageType = itk::Image<unsigned char, 2>;

static void
CreateImage(ImageType::Pointer image);

int
main(int, char *[])
{
  ImageType::Pointer image = ImageType::New();
  CreateImage(image);

  using RegionalMinimaImageFilterType = itk::RegionalMinimaImageFilter<ImageType, ImageType>;
  RegionalMinimaImageFilterType::Pointer regionalMinimaImageFilter = RegionalMinimaImageFilterType::New();
  regionalMinimaImageFilter->SetInput(image);
  regionalMinimaImageFilter->Update();

  using WriterType = itk::ImageFileWriter<ImageType>;
  WriterType::Pointer writer = WriterType::New();
  writer->SetFileName("input.png");
  writer->SetInput(image);
  writer->Update();

  writer->SetFileName("output.png");
  writer->SetInput(regionalMinimaImageFilter->GetOutput());
  writer->Update();

  return EXIT_SUCCESS;
}

void
CreateImage(ImageType::Pointer image)
{
  ImageType::IndexType start;
  start.Fill(0);

  ImageType::SizeType size;
  size[0] = 200;
  size[1] = 300;

  ImageType::RegionType region(start, size);

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

  // Make two intensity blobs
  for (unsigned int r = 0; r < size[1]; r++)
  {
    for (unsigned int c = 0; c < size[0]; c++)
    {
      ImageType::IndexType pixelIndex;
      pixelIndex[0] = c;
      pixelIndex[1] = r;

      double c1 = c - 100.0;
      double c2 = c - 200.0;

      double rr = r - 100.0;

      // purposely use 270,257 since it is > 255
      double v1 = 270.0 - std::sqrt(rr * rr + c1 * c1);
      double v2 = 257.0 - std::sqrt(rr * rr + c2 * c2);

      double maxv = v1;
      if (maxv < v2)
        maxv = v2;

      double val = maxv;

      // Clip
      if (val < 0.0)
        val = 0.0;
      if (val > 255.0)
        val = 255.0;

      image->SetPixel(pixelIndex, static_cast<unsigned char>(val));
    }
  }
}

Classes demonstrated