ITK/Examples/ImageProcessing/BinaryFunctorImageFilterCustom

This example computes the squared difference between corresponding pixels. Note: This functionality is already available in SquaredDifferenceImageFilter. We simply use this as a simple operation to demonstrate the BinaryFunctorImageFilter.

BinaryFunctorImageFilter.cxx

<source lang="cpp">

1. include "itkVectorImage.h"
2. include "itkVector.h"
3. include "itkVariableLengthVector.h"
4. include "itkRigid2DTransform.h"
5. include "itkBinaryFunctorImageFilter.h"

typedef itk::Image<float, 2> ImageType; static void CreateImage(ImageType::Pointer image);

namespace Functor { template< class TPixel> class MySquaredDifference { public:

 MySquaredDifference() {}
 ~MySquaredDifference() {}
 bool operator!=(const MySquaredDifference &) const
 {
   return false;
 }

 bool operator==(const MySquaredDifference & other) const
 {
   return !( *this != other );
 }

 inline TPixel operator()(const TPixel & A,
                           const TPixel & B) const
 {
   const double dA = static_cast< double >( A );
   const double dB = static_cast< double >( B );
   const double diff = dA - dB;

   return static_cast< TPixel >( diff * diff );
 }

}; }

int main(int, char *[]) {

 ImageType::Pointer image1 = ImageType::New();
 CreateImage(image1);
 image1->FillBuffer(2);

 ImageType::Pointer image2 = ImageType::New();
 CreateImage(image2);
 image2->FillBuffer(5);
 
 typedef itk::BinaryFunctorImageFilter< ImageType, ImageType, ImageType,
                           Functor::MySquaredDifference<ImageType::PixelType> > FilterType;

 FilterType::Pointer filter = FilterType::New();
 filter->SetInput1(image1);
 filter->SetInput2(image2);
 filter->Update();

 itk::Index<2> pixelIndex;
 pixelIndex.Fill(0);
 
 ImageType::PixelType input1PixelValue = image1->GetPixel(pixelIndex);
 ImageType::PixelType input2PixelValue = image2->GetPixel(pixelIndex);
 ImageType::PixelType outputPixelValue = filter->GetOutput()->GetPixel(pixelIndex);

 std::cout << "pixel1 was = " << input1PixelValue << std::endl;
 std::cout << "pixel2 was = " << input2PixelValue << std::endl;
 std::cout << "output is = " << outputPixelValue << std::endl;

 return EXIT_SUCCESS;

}

void CreateImage(ImageType::Pointer image) {

 ImageType::IndexType start;
 start.Fill(0);
 
 ImageType::SizeType size;
 size.Fill(10);

 ImageType::RegionType region(start,size);
 image->SetRegions(region);
 image->Allocate();

} </source>

CMakeLists.txt

<syntaxhighlight lang="cmake"> cmake_minimum_required(VERSION 3.9.5)

project(BinaryFunctorImageFilter)

find_package(ITK REQUIRED) include(${ITK_USE_FILE}) if (ITKVtkGlue_LOADED)

 find_package(VTK REQUIRED)
 include(${VTK_USE_FILE})

endif()

add_executable(BinaryFunctorImageFilter MACOSX_BUNDLE BinaryFunctorImageFilter.cxx)

if( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(BinaryFunctorImageFilter ITKReview ${ITK_LIBRARIES})

else( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(BinaryFunctorImageFilter ${ITK_LIBRARIES})

endif( "${ITK_VERSION_MAJOR}" LESS 4 )

</syntaxhighlight>

Download and Build BinaryFunctorImageFilter

Click here to download BinaryFunctorImageFilter and its CMakeLists.txt file. Once the tarball BinaryFunctorImageFilter.tar has been downloaded and extracted,

cd BinaryFunctorImageFilter/build

• If ITK is installed:

cmake ..

• If ITK is not installed but compiled on your system, you will need to specify the path to your ITK build:

cmake -DITK_DIR:PATH=/home/me/itk_build ..

Build the project:

make

and run it:

./BinaryFunctorImageFilter

WINDOWS USERS PLEASE NOTE: Be sure to add the ITK bin directory to your path. This will resolve the ITK dll's at run time.

Building All of the Examples

Many of the examples in the ITK Wiki Examples Collection require VTK. You can build all of the the examples by following these instructions. If you are a new VTK user, you may want to try the Superbuild which will build a proper ITK and VTK.

ItkVtkGlue

ITK >= 4

For examples that use QuickView (which depends on VTK), you must have built ITK with Module_ITKVtkGlue=ON.

ITK < 4

Some of the ITK Examples require VTK to display the images. If you download the entire ITK Wiki Examples Collection, the ItkVtkGlue directory will be included and configured. If you wish to just build a few examples, then you will need to download ItkVtkGlue and build it. When you run cmake it will ask you to specify the location of the ItkVtkGlue binary directory.