Regional Maximal

Synopsis

Regional maximal image filter.

Results

intensityblobs.png

intensityblobs.png

maximal.png

maximal.png

Code

C++

#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkRegionalMaximaImageFilter.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 RegionalMaximaImageFilter = itk::RegionalMaximaImageFilter<ImageType, ImageType>;

  RegionalMaximaImageFilter::Pointer filter = RegionalMaximaImageFilter::New();
  filter->SetInput(image);

  using WriterType = itk::ImageFileWriter<ImageType>;
  WriterType::Pointer writer = WriterType::New();

  writer->SetFileName("intensityblobs.png");
  writer->SetInput(image);
  writer->Update();

  writer->SetFileName("maximal.png");
  writer->SetInput(filter->GetOutput());
  writer->Update();

  return EXIT_SUCCESS;
}

void
CreateImage(ImageType::Pointer image)
{
  // Create an image with 2 connected components
  ImageType::RegionType region;
  ImageType::IndexType  start;
  start[0] = 0;
  start[1] = 0;

  ImageType::SizeType size;
  unsigned int        NumRows = 200;
  unsigned int        NumCols = 300;
  size[0] = NumCols;
  size[1] = NumRows;

  region.SetSize(size);
  region.SetIndex(start);

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

  // Make two intensity blobs
  for (unsigned int r = 0; r < NumRows; r++)
  {
    for (unsigned int c = 0; c < NumCols; 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;

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

      image->SetPixel(pixelIndex, val);
    }
  }
}

Classes demonstrated