[Insight-users] Multi-Resolution Demons with initial Affine

[Emma Saunders]

Hi everyone,

I'm attempting some multi-resolution demons, as input I use an initial
affine transform.  When monitoring convergence however, I get peaks at
every pyramid level (see attached diagram).  Is this normal behaviour

 my pseudocode looks something like:

//Define Demons filter

 RegistrationFilterType::Pointer filter = RegistrationFilterType::New();

//Create initial Affine transform and convert to Displacement field, called
AffineField

  AffineField=converter->GetOutput();

  filter->SetInput(AffineField);
  filter->SetStandardDeviations( 0.8);

//use multiResolution

 MultiResRegistrationFilterType::Pointer multires =
MultiResRegistrationFilterType::New();

  multires->SetRegistrationFilter( filter );
  multires->SetNumberOfLevels( 4 );
  multires->SetFixedImage( FixedImage );
  multires->SetMovingImage( MovedImage );
  unsigned int nIterations[4] = {100, 100, 50, 50 };
  multires->SetNumberOfIterations( nIterations );
  multires->Update();

Am I correct in setting the initial affine field in this manner, does this
set the affine field for the first stage of the pyramid? or is it a case of
the affine field being re-applied at every pyramid value and hence peaks in
the metric

Thoughts appreciated

Thanks

Emma
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20130731/4fca1ab6/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Iter.jpg
Type: image/jpeg
Size: 13496 bytes
Desc: not available
URL: <http://www.itk.org/pipermail/insight-users/attachments/20130731/4fca1ab6/attachment.jpg>