void MutualInformationRegistration::updateRegistration() {
if(!isReady())
return;
convertVolumes();
//typedef itk::RegularStepGradientDescentOptimizer OptimizerType;
typedef itk::VersorRigid3DTransformOptimizer OptimizerType;
typedef OptimizerType::ScalesType OptimizerScalesType;
typedef itk::LinearInterpolateImageFunction< InternalImageType, double > InterpolatorType;
typedef itk::MattesMutualInformationImageToImageMetric< InternalImageType, InternalImageType > MetricType;
typedef itk::MultiResolutionImageRegistrationMethod< InternalImageType, InternalImageType > RegistrationType;
typedef itk::MultiResolutionPyramidImageFilter< InternalImageType, InternalImageType > FixedImagePyramidType;
typedef itk::MultiResolutionPyramidImageFilter< InternalImageType, InternalImageType > MovingImagePyramidType;
OptimizerType::Pointer optimizer = OptimizerType::New();
InterpolatorType::Pointer interpolator = InterpolatorType::New();
RegistrationType::Pointer registration = RegistrationType::New();
MetricType::Pointer metric = MetricType::New();
FixedImagePyramidType::Pointer fixedImagePyramid = FixedImagePyramidType::New();
MovingImagePyramidType::Pointer movingImagePyramid = MovingImagePyramidType::New();
registration->SetOptimizer(optimizer);
registration->SetTransform(transform_);
registration->SetInterpolator(interpolator);
registration->SetMetric(metric);
registration->SetFixedImagePyramid(fixedImagePyramid);
registration->SetMovingImagePyramid(movingImagePyramid);
OptimizerScalesType optimizerScales( transform_->GetNumberOfParameters() );
float rotScale = 1.0 / 1000.0f;
optimizerScales[0] = 1.0f;
optimizerScales[1] = 1.0f;
optimizerScales[2] = 1.0f;
optimizerScales[3] = rotScale;
optimizerScales[4] = rotScale;
optimizerScales[5] = rotScale;
optimizer->SetScales( optimizerScales );
optimizer->SetMaximumStepLength(0.2);
optimizer->SetMinimumStepLength(0.0001);
InternalImageType::Pointer fixed = voreenToITK<float>(fixedVolumeFloat_);
InternalImageType::Pointer moving = voreenToITK<float>(movingVolumeFloat_);
registration->SetFixedImage(fixed);
registration->SetMovingImage(moving);
registration->SetFixedImageRegion( fixed->GetBufferedRegion() );
registration->SetInitialTransformParameters( transform_->GetParameters() );
metric->SetNumberOfHistogramBins(numHistogramBins_.get());
size_t numVoxels = hmul(fixedVolumeFloat_->getDimensions());
metric->SetNumberOfSpatialSamples(numVoxels * numSamples_.get());
metric->ReinitializeSeed( 76926294 );
//// Define whether to calculate the metric derivative by explicitly
//// computing the derivatives of the joint PDF with respect to the Transform
//// parameters, or doing it by progressively accumulating contributions from
//// each bin in the joint PDF.
metric->SetUseExplicitPDFDerivatives(explicitPDF_.get());
optimizer->SetNumberOfIterations(numIterations_.get());
optimizer->SetRelaxationFactor(relaxationFactor_.get());
// Create the Command observer and register it with the optimizer.
CommandIterationUpdate::Pointer observer = CommandIterationUpdate::New();
optimizer->AddObserver( itk::IterationEvent(), observer );
typedef RegistrationInterfaceCommand<RegistrationType> CommandType;
CommandType::Pointer command = CommandType::New();
registration->AddObserver( itk::IterationEvent(), command );
registration->SetNumberOfLevels(numLevels_.get());
try
{
registration->StartRegistration();
std::cout << "Optimizer stop condition: " << registration->GetOptimizer()->GetStopConditionDescription() << std::endl;
}
catch( itk::ExceptionObject & err )
{
std::cout << "ExceptionObject caught !" << std::endl;
std::cout << err << std::endl;
//return EXIT_FAILURE;
}
ParametersType finalParameters = registration->GetLastTransformParameters();
transform_->SetParameters(finalParameters);
unsigned int numberOfIterations = optimizer->GetCurrentIteration();
double bestValue = optimizer->GetValue();
// Print out results
std::cout << "Result = " << std::endl;
std::cout << " Versor " << finalParameters[0] << " " << finalParameters[1] << " " << finalParameters[2] << std::endl;
std::cout << " Translation " << finalParameters[1] << " " << finalParameters[4] << " " << finalParameters[5] << std::endl;
std::cout << " Iterations = " << numberOfIterations << std::endl;
std::cout << " Metric value = " << bestValue << std::endl;
invalidate(INVALID_RESULT);
}
