ITK/Examples/ImageProcessing/InvertIntensityImageFilter

This example demonstrates how to invert the intensity of pixels by subtracting each pixel value from a specified maximum value. The output shows the original image and the inverted image.

InvertIntensityImageFilter.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkRescaleIntensityImageFilter.h"
3. include "itkInvertIntensityImageFilter.h"
4. include "itkImageFileReader.h"

1. include "itkImageToVTKImageFilter.h"

1. include "vtkImageViewer.h"
2. include "vtkRenderWindowInteractor.h"
3. include "vtkSmartPointer.h"
4. include "vtkImageActor.h"
5. include "vtkInteractorStyleImage.h"
6. include "vtkRenderer.h"

typedef itk::Image<unsigned char, 2> ImageType;

static void CreateImage(ImageType::Pointer image);

int main(int, char *[]) {

 ImageType::Pointer image = ImageType::New();
 CreateImage(image);

 typedef itk::InvertIntensityImageFilter <ImageType>
   InvertIntensityImageFilterType;

 InvertIntensityImageFilterType::Pointer invertIntensityFilter
   = InvertIntensityImageFilterType::New();
 invertIntensityFilter->SetInput(image);
 invertIntensityFilter->SetMaximum(50);
 invertIntensityFilter->Update();

 // Visualize first image
 typedef itk::ImageToVTKImageFilter<ImageType> ConnectorType;
 ConnectorType::Pointer originalConnector = ConnectorType::New();
 originalConnector->SetInput(image);

 vtkSmartPointer<vtkImageActor> originalActor =
   vtkSmartPointer<vtkImageActor>::New();
 originalActor->SetInput(originalConnector->GetOutput());

 // Visualize inverted image
 ConnectorType::Pointer invertedConnector = ConnectorType::New();
 invertedConnector->SetInput(invertIntensityFilter->GetOutput());

 vtkSmartPointer<vtkImageActor> invertedActor =
   vtkSmartPointer<vtkImageActor>::New();
 invertedActor->SetInput(invertedConnector->GetOutput());

 // There will be one render window
 vtkSmartPointer<vtkRenderWindow> renderWindow =
   vtkSmartPointer<vtkRenderWindow>::New();
 renderWindow->SetSize(600, 300);

 vtkSmartPointer<vtkRenderWindowInteractor> interactor =
   vtkSmartPointer<vtkRenderWindowInteractor>::New();
 interactor->SetRenderWindow(renderWindow);

 // Define viewport ranges
 // (xmin, ymin, xmax, ymax)
 double leftViewport[4] = {0.0, 0.0, 0.5, 1.0};
 double rightViewport[4] = {0.5, 0.0, 1.0, 1.0};

 // Setup both renderers
 vtkSmartPointer<vtkRenderer> leftRenderer =
   vtkSmartPointer<vtkRenderer>::New();
 renderWindow->AddRenderer(leftRenderer);
 leftRenderer->SetViewport(leftViewport);
 leftRenderer->SetBackground(.6, .5, .4);

 vtkSmartPointer<vtkRenderer> rightRenderer =
   vtkSmartPointer<vtkRenderer>::New();
 renderWindow->AddRenderer(rightRenderer);
 rightRenderer->SetViewport(rightViewport);
 rightRenderer->SetBackground(.4, .5, .6);

 // Add the sphere to the left and the cube to the right
 leftRenderer->AddActor(originalActor);
 rightRenderer->AddActor(invertedActor);

 leftRenderer->ResetCamera();
 rightRenderer->ResetCamera();

 renderWindow->Render();

 vtkSmartPointer<vtkInteractorStyleImage> style =
   vtkSmartPointer<vtkInteractorStyleImage>::New();
 interactor->SetInteractorStyle(style);

 interactor->Start();

 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);
     }
   }

} </source>

CMakeLists.txt

<source lang="cmake"> cmake_minimum_required(VERSION 2.6)

PROJECT(InvertIntensityImageFilter)

include_directories(/home/doriad/src/ITK/Wrapping/WrapITK/ExternalProjects/ItkVtkGlue/src/)

FIND_PACKAGE(VTK REQUIRED) INCLUDE(${VTK_USE_FILE})

FIND_PACKAGE(ITK REQUIRED) INCLUDE(${ITK_USE_FILE})

ADD_EXECUTABLE(InvertIntensityImageFilter InvertIntensityImageFilter.cxx) TARGET_LINK_LIBRARIES(InvertIntensityImageFilter vtkHybrid ITKBasicFilters ITKCommon ITKIO)

</source>