Compare Two Images and Set Output Pixel to Min

Synopsis

Pixel wise compare two input images and set the output pixel to their min.

Results

Note

No output is printed, this example simply displays functionality.

Code

C++

#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkMinimumImageFilter.h"
#include "itkImageFileReader.h"
#include "itkImageRegionIterator.h"

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

static void
CreateImage1(ImageType * image);
static void
CreateImage2(ImageType * image);

int
main(int, char *[])
{
  ImageType::Pointer image1 = ImageType::New();
  CreateImage1(image1);

  ImageType::Pointer image2 = ImageType::New();
  CreateImage2(image2);

  using MinimumImageFilterType = itk::MinimumImageFilter<ImageType>;

  MinimumImageFilterType::Pointer minimumImageFilter = MinimumImageFilterType::New();
  minimumImageFilter->SetInput(0, image1);
  minimumImageFilter->SetInput(1, image2);
  minimumImageFilter->Update();

  return EXIT_SUCCESS;
}

void
CreateImage1(ImageType * image)
{
  ImageType::IndexType start;
  start.Fill(0);

  ImageType::SizeType size;
  size.Fill(100);

  ImageType::RegionType region;
  region.SetSize(size);
  region.SetIndex(start);

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

  itk::ImageRegionIterator<ImageType> imageIterator(image, region);

  while (!imageIterator.IsAtEnd())
  {
    if (imageIterator.GetIndex()[0] < 30)
    {
      imageIterator.Set(255);
    }
    else
    {
      imageIterator.Set(0);
    }

    ++imageIterator;
  }
}

void
CreateImage2(ImageType * image)
{
  ImageType::IndexType start;
  start.Fill(0);

  ImageType::SizeType size;
  size.Fill(100);

  ImageType::RegionType region;
  region.SetSize(size);
  region.SetIndex(start);

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

  itk::ImageRegionIterator<ImageType> imageIterator(image, region);

  while (!imageIterator.IsAtEnd())
  {
    if (imageIterator.GetIndex()[0] > 70)
    {
      imageIterator.Set(255);
    }
    else
    {
      imageIterator.Set(0);
    }

    ++imageIterator;
  }
}

Classes demonstrated

template<typename TInputImage1, typename TInputImage2 = TInputImage1, typename TOutputImage = TInputImage1>
class MinimumImageFilter : public itk::BinaryGeneratorImageFilter<TInputImage1, TInputImage2, TOutputImage>

Implements a pixel-wise operator Min(a,b) between two images.

The pixel values of the output image are the minimum between the corresponding pixels of the two input images.

This class is templated over the types of the two input images and the type of the output image. Numeric conversions (castings) are done by the C++ defaults.

ITK Sphinx Examples:

• All ITK Sphinx Examples

• Compare Two Images And Set Output Pixel To Min

See itk::MinimumImageFilter for additional documentation.