Invert Image

Synopsis

Invert an image.

Results

Output In VTK Window

Code

C++

#include "itkImage.h"
#include "itkInvertIntensityImageFilter.h"
#include "itkImageFileReader.h"

#ifdef ENABLE_QUICKVIEW
#  include "QuickView.h"
#endif

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

static void
CreateImage(ImageType::Pointer image);

int
main(int argc, char * argv[])
{
  ImageType::Pointer image = ImageType::New();
  std::stringstream  desc;

  CreateImage(image);

  unsigned int maximum = 255;
  if (argc > 1)
  {
    using ReaderType = itk::ImageFileReader<ImageType>;
    ReaderType::Pointer reader = ReaderType::New();
    reader->SetFileName(argv[1]);
    reader->Update();
    image = reader->GetOutput();
    desc << itksys::SystemTools::GetFilenameName(argv[1]);
    if (argc > 2)
    {
      maximum = std::stoi(argv[2]);
    }
  }
  else
  {
    CreateImage(image);
    desc << "Synthetic image";
    maximum = 50;
  }

  using InvertIntensityImageFilterType = itk::InvertIntensityImageFilter<ImageType>;

  InvertIntensityImageFilterType::Pointer invertIntensityFilter = InvertIntensityImageFilterType::New();
  invertIntensityFilter->SetInput(image);
  invertIntensityFilter->SetMaximum(maximum);

#ifdef ENABLE_QUICKVIEW
  QuickView viewer;
  viewer.AddImage(image.GetPointer(), true, desc.str());

  std::stringstream desc2;
  desc2 << "InvertIntensity, maximum = " << maximum;
  viewer.AddImage(invertIntensityFilter->GetOutput(), true, desc2.str());

  viewer.Visualize();
#endif
  return EXIT_SUCCESS;
}

void
CreateImage(ImageType::Pointer image)
{
  // Create an image
  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] = NumRows;
  size[1] = NumCols;

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

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

  // Make a square
  for (unsigned int r = 40; r < 100; r++)
  {
    for (unsigned int c = 40; c < 100; c++)
    {
      ImageType::IndexType pixelIndex;
      pixelIndex[0] = r;
      pixelIndex[1] = c;

      image->SetPixel(pixelIndex, 50);
    }
  }
}

Classes demonstrated

template<typename TInputImage, typename TOutputImage = TInputImage>
class InvertIntensityImageFilter : public itk::UnaryFunctorImageFilter<TInputImage, TOutputImage, Functor::InvertIntensityTransform<TInputImage::PixelType, TOutputImage::PixelType>>

Invert the intensity of an image.

InvertIntensityImageFilter inverts intensity of pixels by subtracting pixel value to a maximum value. The maximum value can be set with SetMaximum and defaults the maximum of input pixel type. This filter can be used to invert, for example, a binary image, a distance map, etc.

Author

Gaetan Lehmann. Biologie du Developpement et de la Reproduction, INRA de Jouy-en-Josas, France.

See

IntensityWindowingImageFilter ShiftScaleImageFilter

ITK Sphinx Examples:

• All ITK Sphinx Examples

• Invert Image

See itk::InvertIntensityImageFilter for additional documentation.