typename TImage::Pointer modelBasedImageToImageRegistration(std::string referenceFilename,
std::string targetFilename,
typename TStatisticalModelType::Pointer model,
std::string outputDfFilename,
unsigned numberOfIterations){
typedef itk::ImageFileReader<TImage> ImageReaderType;
typedef itk::InterpolatingStatisticalDeformationModelTransform<TRepresenter, double, VImageDimension> TransformType;
typedef itk::LBFGSOptimizer OptimizerType;
typedef itk::ImageRegistrationMethod<TImage, TImage> RegistrationFilterType;
typedef itk::WarpImageFilter< TImage, TImage, TVectorImage > WarperType;
typedef itk::LinearInterpolateImageFunction< TImage, double > InterpolatorType;
typename ImageReaderType::Pointer referenceReader = ImageReaderType::New();
referenceReader->SetFileName(referenceFilename.c_str());
referenceReader->Update();
typename TImage::Pointer referenceImage = referenceReader->GetOutput();
referenceImage->Update();
typename ImageReaderType::Pointer targetReader = ImageReaderType::New();
targetReader->SetFileName(targetFilename.c_str());
targetReader->Update();
typename TImage::Pointer targetImage = targetReader->GetOutput();
targetImage->Update();
// do the fitting
typename TransformType::Pointer transform = TransformType::New();
transform->SetStatisticalModel(model);
transform->SetIdentity();
// Setting up the fitting
OptimizerType::Pointer optimizer = OptimizerType::New();
optimizer->MinimizeOn();
optimizer->SetMaximumNumberOfFunctionEvaluations(numberOfIterations);
typedef IterationStatusObserver ObserverType;
ObserverType::Pointer observer = ObserverType::New();
optimizer->AddObserver( itk::IterationEvent(), observer );
typename TMetricType::Pointer metric = TMetricType::New();
typename InterpolatorType::Pointer interpolator = InterpolatorType::New();
typename RegistrationFilterType::Pointer registration = RegistrationFilterType::New();
registration->SetInitialTransformParameters(transform->GetParameters());
registration->SetMetric(metric);
registration->SetOptimizer( optimizer );
registration->SetTransform( transform );
registration->SetInterpolator( interpolator );
registration->SetFixedImage( targetImage );
registration->SetFixedImageRegion(targetImage->GetBufferedRegion() );
registration->SetMovingImage( referenceImage );
try {
std::cout << "Performing registration... " << std::flush;
registration->Update();
std::cout << "[done]" << std::endl;
} catch ( itk::ExceptionObject& o ) {
std::cout << "caught exception " << o << std::endl;
}
typename TVectorImage::Pointer df = model->DrawSample(transform->GetCoefficients());
// write deformation field
if(outputDfFilename.size()>0){
typename itk::ImageFileWriter<TVectorImage>::Pointer df_writer = itk::ImageFileWriter<TVectorImage>::New();
df_writer->SetFileName(outputDfFilename);
df_writer->SetInput(df);
df_writer->Update();
}
// warp reference
std::cout << "Warping reference... " << std::flush;
typename WarperType::Pointer warper = WarperType::New();
warper->SetInput(referenceImage );
warper->SetInterpolator( interpolator );
warper->SetOutputSpacing( targetImage->GetSpacing() );
warper->SetOutputOrigin( targetImage->GetOrigin() );
warper->SetOutputDirection( targetImage->GetDirection() );
warper->SetDisplacementField( df );
warper->Update();
std::cout << "[done]" << std::endl;
return warper->GetOutput();
}
