[Insight-users] What optimizer and transform can/should I use?

[Yu Qi]

Hi,
I tried the Versor transform function and optimizer.
and following is the code for metric
 
 unsigned int numberOfBins =32;
  MetricType::HistogramType::SizeType histogramSize;
  histogramSize[0] = numberOfBins;
  histogramSize[1] = numberOfBins;
  metric->SetHistogramSize( histogramSize );
 
  const unsigned int numberOfParameters = transform->GetNumberOfParameters();
  typedef MetricType::ScalesType ScalesType;
  ScalesType scales( numberOfParameters );
  scales.Fill( 1.0 );
    
  metric->SetDerivativeStepLengthScales(scales);
 
 
I do not know why the computation was so slow.
Every iteration will take 2 second.
Do you know why?
 
Thanks!
Best regards,
Yu Qi
 
 
 
Luis Ibanez <luis.ibanez at kitware.com> 写道：

Hi Yu,


The Optimizers to use depends a lot on the Transform
that you choose. Therefore the decision about the
Transform should be taken first.

Since this is 3D and you probably are dealing with
images from the same patient, I would suggest that
you use a rigid Transform such as:

VersorRigid3DTransform
http://www.itk.org/Insight/Doxygen/html/classitk_1_1VersorRigid3DTransform.html

and therefore use the

VersorRigid3DTransformOptimizer
http://www.itk.org/Insight/Doxygen/html/classitk_1_1VersorRigid3DTransformOptimizer.html


There are multiple options for Mutual Information, but
if you insist in using Normalized Mutual Information,
then the class that you need is:

http://www.itk.org/Insight/Doxygen/html/classitk_1_1NormalizedMutualInformationHistogramImageToImageMetric.html


You will find a versy similar example on the
ITK Software Guide

http://www.itk.org/ItkSoftwareGuide.pdf

in section: 8.6.4, pdf-page 391. The source code is
available in


Insight/Examples/Registration/
ImageRegistration8.cxx



You are *STRONGLY* encouraged to read the full Chapter
on registration before you attempt to use this particular
example.



Regards,


Luis



--------------
Yu Qi wrote:
> Hi.
> I am going to register 3d MRI and fMRI using Normalized MI metric.
> 
> What optimizer and transform can I use?
> Can I use any of the transform and optimizer supplied by ITK?
> 
> And which is the most popular one for normalized MI?
> 
> Thank you!
> 
> 
> 
> 
> *Best Regards!*
> ** 
> *Yu Qi*
> 
> 
> 



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