ITK/Examples/SpectralAnalysis/CrossCorrelationInFourierDomain

CrossCorrelationInFourierDomain.cxx

<source lang="cpp">

1. include "itkImage.h"
2. include "itkImageFileReader.h"
3. include "itkImageFileWriter.h"

1. include "itkVnlFFTRealToComplexConjugateImageFilter.h"
2. include "itkVnlFFTComplexConjugateToRealImageFilter.h"
3. include "itkComplexToRealImageFilter.h"
4. include "itkComplexToImaginaryImageFilter.h"
5. include "itkRealAndImaginaryToComplexImageFilter.h"
6. include "itkMultiplyImageFilter.h"
7. include "itkRescaleIntensityImageFilter.h"
8. include "itkFFTShiftImageFilter.h"
9. include "itkMinimumMaximumImageCalculator.h"

1. if ITK_VERSION_MAJOR < 4
2. include "itkMultiplyByConstantImageFilter.h"
3. endif

int main(int argc, char*argv[]) {

 const    unsigned int    Dimension = 2;
 typedef  float                                  PixelType;
 typedef itk::Image< PixelType, Dimension >      FloatImageType;
 typedef itk::Image< unsigned char, Dimension >  UnsignedCharImageType;

 if( argc < 3 )
   {
   std::cerr << "Missing Parameters " << std::endl;
   std::cerr << "Usage: " << argv[0];
   std::cerr << " FixedImage MovingImage"<< std::endl;;
   return EXIT_FAILURE;
   }
 std::string fixedImageFilename = argv[1];
 std::string movingImageFilename = argv[2];

 // Read the input images
 typedef itk::ImageFileReader< FloatImageType  > ImageReaderType;
 ImageReaderType::Pointer  fixedImageReader  = ImageReaderType::New();
 fixedImageReader->SetFileName( fixedImageFilename );
 fixedImageReader->Update();
 
 ImageReaderType::Pointer movingImageReader = ImageReaderType::New();
 movingImageReader->SetFileName( movingImageFilename );
 movingImageReader->Update();

 // Shift the input images
 typedef itk::FFTShiftImageFilter< FloatImageType, FloatImageType > FFTShiftFilterType;
 FFTShiftFilterType::Pointer fixedFFTShiftFilter = FFTShiftFilterType::New();
 fixedFFTShiftFilter->SetInput(fixedImageReader->GetOutput());
 fixedFFTShiftFilter->Update();

 FFTShiftFilterType::Pointer movingFFTShiftFilter = FFTShiftFilterType::New();
 movingFFTShiftFilter->SetInput(movingImageReader->GetOutput());
 movingFFTShiftFilter->Update();
 
 // Compute the FFT of the input
 typedef itk::VnlFFTRealToComplexConjugateImageFilter< FloatImageType >  FFTFilterType;
 FFTFilterType::Pointer fixedFFTFilter = FFTFilterType::New();
 fixedFFTFilter->SetInput( fixedFFTShiftFilter->GetOutput() );
 fixedFFTFilter->Update();
 
 FFTFilterType::Pointer movingFFTFilter = FFTFilterType::New();
 movingFFTFilter->SetInput( movingFFTShiftFilter->GetOutput() );
 
 typedef FFTFilterType::OutputImageType    SpectralImageType;

 // Take the conjugate of the fftFilterMoving
 // Extract the real part
 typedef itk::ComplexToRealImageFilter<SpectralImageType, FloatImageType> RealFilterType;
 RealFilterType::Pointer realFilter = RealFilterType::New();
 realFilter->SetInput(movingFFTFilter->GetOutput());

 // Extract the imaginary part
 typedef itk::ComplexToImaginaryImageFilter<SpectralImageType, FloatImageType> ImaginaryFilterType;
 ImaginaryFilterType::Pointer imaginaryFilter = ImaginaryFilterType::New();
 imaginaryFilter->SetInput(movingFFTFilter->GetOutput());

 // Flip the sign of the imaginary and combine with the real part again

1. if ITK_VERSION_MAJOR < 4

 typedef itk::MultiplyByConstantImageFilter<FloatImageType,PixelType,FloatImageType> MultiplyConstantFilterType;

1. else

 typedef itk::MultiplyImageFilter<FloatImageType,FloatImageType,FloatImageType> MultiplyConstantFilterType;

1. endif

 MultiplyConstantFilterType::Pointer flipSignFilter = MultiplyConstantFilterType::New();

1. if ITK_VERSION_MAJOR < 4

 flipSignFilter->SetConstant(-1);

1. else

 flipSignFilter->SetConstant2(-1);

1. endif

 flipSignFilter->SetInput(imaginaryFilter->GetOutput());
 typedef itk::RealAndImaginaryToComplexImageFilter<FloatImageType> RealImageToComplexFilterType;
 RealImageToComplexFilterType::Pointer conjugateFilter = RealImageToComplexFilterType::New();
 conjugateFilter->SetInput1(realFilter->GetOutput());
 conjugateFilter->SetInput2(flipSignFilter->GetOutput());

 // The conjugate product of the spectrum
 typedef itk::MultiplyImageFilter< SpectralImageType,
   SpectralImageType,
   SpectralImageType >  MultiplyFilterType;
 MultiplyFilterType::Pointer multiplyFilter = MultiplyFilterType::New();
 multiplyFilter->SetInput1( fixedFFTFilter->GetOutput() );
 multiplyFilter->SetInput2( conjugateFilter->GetOutput() );

 // IFFT
 typedef itk::VnlFFTComplexConjugateToRealImageFilter< SpectralImageType >  IFFTFilterType;
 IFFTFilterType::Pointer fftInverseFilter = IFFTFilterType::New();
 fftInverseFilter->SetInput( multiplyFilter->GetOutput() );

 // Write the spectrum
 typedef itk::RescaleIntensityImageFilter< FloatImageType,  UnsignedCharImageType > RescaleFilterType;
 RescaleFilterType::Pointer  rescaler =  RescaleFilterType::New();
 rescaler->SetInput( fftInverseFilter->GetOutput() );
 rescaler->SetOutputMinimum(0);
 rescaler->SetOutputMaximum(255);
 rescaler->Update();
   
 typedef itk::ImageFileWriter< UnsignedCharImageType >  WriterType;
 WriterType::Pointer writer =  WriterType::New();
 writer->SetFileName( "CrossCorr.png" );
 writer->SetInput( rescaler->GetOutput() );
 writer->Update();

 typedef itk::MinimumMaximumImageCalculator <UnsignedCharImageType>
   ImageCalculatorFilterType;

 ImageCalculatorFilterType::Pointer imageCalculatorFilter
   = ImageCalculatorFilterType::New ();
 imageCalculatorFilter->SetImage(rescaler->GetOutput());
 imageCalculatorFilter->Compute();
 
 UnsignedCharImageType::IndexType maximumLocation = imageCalculatorFilter->GetIndexOfMaximum();
 std::cout << maximumLocation << std::endl; // should be (17,15)
 
 /*
 if ypeak < size(I,1)/2 ypeak = -(ypeak-1);
 else ypeak = size(I,1) - (ypeak-1);
 end
 if xpeak < size(I,2)/2 xpeak = -(xpeak-1);
 else xpeak = size(I,2) - (xpeak-1);
 end
 */
 
 return EXIT_SUCCESS;

} </source>

CMakeLists.txt

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

project(CrossCorrelationInFourierDomain)

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

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

endif()

add_executable(CrossCorrelationInFourierDomain MACOSX_BUNDLE CrossCorrelationInFourierDomain.cxx)

if( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(CrossCorrelationInFourierDomain ITKReview ${ITK_LIBRARIES})

else( "${ITK_VERSION_MAJOR}" LESS 4 )

 target_link_libraries(CrossCorrelationInFourierDomain ${ITK_LIBRARIES})

endif( "${ITK_VERSION_MAJOR}" LESS 4 )

</syntaxhighlight>

Download and Build CrossCorrelationInFourierDomain

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

cd CrossCorrelationInFourierDomain/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:

./CrossCorrelationInFourierDomain

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.