Invert Image Using Binary Not Operation#

Synopsis#

Invert an image using the Binary Not operation.

Results#

../../../../_images/Input8.png — input.png#

../../../../_images/output9.png — output.png#

Code#

C++#

#include "itkImage.h"
#if ITK_VERSION_MAJOR >= 4
#  include "itkBinaryNotImageFilter.h"
#endif
#include "itkImageRegionIterator.h"
#include "itkImageFileWriter.h"

using ImageType = itk::Image<unsigned char, 2>;
static void
CreateImage(ImageType::Pointer image);

int
main()
{
#if ITK_VERSION_MAJOR >= 4
  auto image = ImageType::New();
  CreateImage(image);

  itk::WriteImage(image, "input.png");

  using BinaryNotImageFilterType = itk::BinaryNotImageFilter<ImageType>;

  auto binaryNotFilter = BinaryNotImageFilterType::New();
  binaryNotFilter->SetInput(image);
  binaryNotFilter->Update();

  itk::WriteImage(binaryNotFilter->GetOutput(), "output.png");
#endif

  return EXIT_SUCCESS;
}
void
CreateImage(ImageType::Pointer 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] > 50)
    {
      imageIterator.Set(255);
    }
    else
    {
      imageIterator.Set(0);
    }

    ++imageIterator;
  }
}

Classes demonstrated#

template<typename TImage> class BinaryNotImageFilter : public itk::UnaryFunctorImageFilter<TImage, TImage, Functor::BinaryNot<TImage::PixelType>>

Implements the BinaryNot logical operator pixel-wise between two images.

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

The total operation over one pixel will be

output_pixel = static_cast<PixelType>( input1_pixel != input2_pixel )

Where “!=” is the equality operator in C++.

This implementation was taken from the Insight Journal paper:

https://www.insight-journal.org/browse/publication/176