ITK/Examples/ImageProcessing/AbsImageFilter

This example demonstrates how to compute the absolute value of each pixel in an image. The output shows the input image and the absolute value image. The input image, by necessity of this demonstration, has negative pixel values. This type of image is impossible to display directly, so it is scaled and shifted before being displayed so its values are in the range (0,255).

AbsImageFilter.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkImageFileWriter.h"
3. include "itkRescaleIntensityImageFilter.h"
4. include "itkAbsImageFilter.h"

1. include "QuickView.h"

typedef itk::Image<unsigned char, 2> UnsignedCharImageType; typedef itk::Image<float, 2> FloatImageType;

static void CreateImage(FloatImageType::Pointer image);

int main(int, char *[]) {

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

 // Take the absolute value of the image
 typedef itk::AbsImageFilter <FloatImageType, FloatImageType>
         AbsImageFilterType;

 AbsImageFilterType::Pointer absFilter
         = AbsImageFilterType::New ();
 absFilter->SetInput(image);

 QuickView viewer;
 viewer.AddImage<FloatImageType>(image);
 viewer.AddImage<FloatImageType>(absFilter->GetOutput());
 viewer.Visualize();

 return EXIT_SUCCESS;

}

void CreateImage(FloatImageType::Pointer image) {

 // Create an image with negative values
 FloatImageType::RegionType region;
 FloatImageType::IndexType start;
 start[0] = 0;
 start[1] = 0;

 FloatImageType::SizeType size;
 size[0] = 200;
 size[1] = 300;

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

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

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

 while(!imageIterator.IsAtEnd())
   {
   imageIterator.Set(imageIterator.GetIndex()[0] - imageIterator.GetIndex()[1]);
   ++imageIterator;
   }
 

} </source>

CMakeLists.txt

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

PROJECT(AbsImageFilter)

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(AbsImageFilter AbsImageFilter.cxx) TARGET_LINK_LIBRARIES(AbsImageFilter vtkHybrid ITKBasicFilters ITKCommon ITKIO)

</source>