[Insight-users] Problem with BSplines-Registration and Mutual Information Metric

[TienGarry]

metric->SetNumberOfSpatialSamples( numberOfSamples );it seems that mutualinformation method only uses part of the image samples,
itkMeanSquaresImageToImageMetric  uses all the image pixels. It is not surprise
for you to get the result for same modality image registration.
Guys, is it right?> Date: Fri, 19 Dec 2008 17:00:24 +0100> From: carola.schmidt at igd.fraunhofer.de> To: insight-users at itk.org> Subject: [Insight-users] Problem with BSplines-Registration and Mutual Information Metric> > Hi, itk users.> > I am implementing the BSpline Registration to register CT-Data of the > abdomen. I use the LBFGSBOptimizer> and use the parameters of the deformableRegistration8.cxx file> > OptimizerType::BoundSelectionType > boundSelect(transform->GetNumberOfParameters());> OptimizerType::BoundValueType > upperBound(transform->GetNumberOfParameters());> OptimizerType::BoundValueType > lowerBound(transform->GetNumberOfParameters());> > boundSelect.Fill(0);> upperBound.Fill(0.0);> lowerBound.Fill(0.0);> > optimizer->SetBoundSelection(boundSelect);> optimizer->SetUpperBound(upperBound);> optimizer->SetLowerBound(lowerBound);> > optimizer->SetCostFunctionConvergenceFactor( 1e+7 );> optimizer->SetProjectedGradientTolerance( 1e-4 );> optimizer->SetMaximumNumberOfIterations( 500 );> optimizer->SetMaximumNumberOfEvaluations( 500 );> optimizer->SetMaximumNumberOfCorrections( 12 );> > > As metrics I tried itkMeanSquaresImageToImageMetric and > itkMattesMutualInformationImageToImageMetric. When I use the > itkMeanSquaresImageToImageMetric the registration takes really long but > the results are quite ok.> When I use itkMattesMutualInformationImageToImageMetric the registration > only takes a few seconds but most of the time the warped image looks > like a hardly deformed moving image. Since the registration time is very > short, it seems that the registration stops after a few steps and warps > the image then. I use those parameters for the mututal information:> > metric->SetNumberOfHistogramBins( 40 );> const unsigned int numberOfSamples = 10000; > //fixedRegion.GetNumberOfPixels()/ 10;> metric->SetNumberOfSpatialSamples( numberOfSamples );> metric->ReinitializeSeed( 76926294 );> metric->SetMovingImage(m_itkimage);> metric->SetFixedImage(m_itkatlas);> metric->SetFixedImageRegion(fixedRegion);> > Why does the Mutual Information Metric not work as expected? Should I > change the parameters of the optimizer?> Thanks for an answer.> > Ciao,> Carola> _______________________________________________> Insight-users mailing list> Insight-users at itk.org> http://www.itk.org/mailman/listinfo/insight-users
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