ITK  5.0.0
Insight Segmentation and Registration Toolkit
Examples/RegistrationITKv3/DisplacementFieldInitialization.cxx
/*=========================================================================
*
* Copyright Insight Software Consortium
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
// Software Guide : BeginLatex
//
// In order to initialize deformable registration algorithm it is often
// convenient to generate a displacemnt field from a set of feature
// correspondances provided by the user. The following example illustrates how
// to use the \doxygen{itkLandmarkDisplacementFieldSource} class in order to generate a
// displacement field from the specification of two sets of landmarks.
// Landmarks from one set are associated one-to-one to the landmarks in the
// other set. Each landmark pair defines one displacement vector. This class
// interpolates the values of all other displacement vectors using
// \doxygen{KernelBasedTransform}
//
//
// \index{Registration!Finite Element-Based}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
#include "itkImage.h"
#include "itkVector.h"
#include <fstream>
int main( int argc, char * argv[] )
{
if( argc < 3 )
{
std::cerr << "Missing Parameters " << std::endl;
std::cerr << "Usage: " << argv[0];
std::cerr << " landmarksFile fixedImage outputDisplacementField"
<< std::endl;
return EXIT_FAILURE;
}
constexpr unsigned int Dimension = 2;
using VectorComponentType = float;
using DisplacementFieldType = itk::Image< VectorType, Dimension >;
using PixelType = unsigned char;
using FixedImageType = itk::Image< PixelType, Dimension >;
using FixedReaderType = itk::ImageFileReader< FixedImageType >;
FixedReaderType::Pointer fixedReader = FixedReaderType::New();
fixedReader->SetFileName( argv[2] );
try
{
fixedReader->Update();
}
catch( itk::ExceptionObject & excp )
{
std::cerr << "Exception thrown " << std::endl;
std::cerr << excp << std::endl;
return EXIT_FAILURE;
}
FixedImageType::ConstPointer fixedImage = fixedReader->GetOutput();
FilterType::Pointer filter = FilterType::New();
filter->SetOutputSpacing( fixedImage->GetSpacing() );
filter->SetOutputOrigin( fixedImage->GetOrigin() );
filter->SetOutputRegion( fixedImage->GetLargestPossibleRegion() );
filter->SetOutputDirection( fixedImage->GetDirection() );
// Create source and target landmarks.
//
using LandmarkContainerType = FilterType::LandmarkContainer;
using LandmarkPointType = FilterType::LandmarkPointType;
LandmarkContainerType::Pointer sourceLandmarks
= LandmarkContainerType::New();
LandmarkContainerType::Pointer targetLandmarks
= LandmarkContainerType::New();
std::ifstream pointsFile;
pointsFile.open( argv[1] );
LandmarkPointType sourcePoint;
pointsFile >> sourcePoint;
LandmarkPointType targetPoint;
pointsFile >> targetPoint;
unsigned int pointId = 0;
while( !pointsFile.fail() )
{
sourceLandmarks->InsertElement( pointId, sourcePoint );
targetLandmarks->InsertElement( pointId, targetPoint );
pointId++;
pointsFile >> sourcePoint;
pointsFile >> targetPoint;
}
pointsFile.close();
filter->SetSourceLandmarks( sourceLandmarks );
filter->SetTargetLandmarks( targetLandmarks );
try
{
filter->UpdateLargestPossibleRegion();
}
catch( itk::ExceptionObject & excp )
{
std::cerr << "Exception thrown " << std::endl;
std::cerr << excp << std::endl;
return EXIT_FAILURE;
}
// Write an image for regression testing
WriterType::Pointer writer = WriterType::New();
writer->SetInput ( filter->GetOutput() );
writer->SetFileName( argv[3] );
filter->Print( std::cout );
try
{
writer->Update();
}
catch( itk::ExceptionObject & excp )
{
std::cerr << "Exception thrown by writer" << std::endl;
std::cerr << excp << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
// Software Guide : EndLatex
}