[Insight-users] FEM Scaling problem

[Felix Bollenbeck]

Hi all,

Im using the FEMRegistrationFilter for non-rigid Registration.

Using a smaller scale, I experienced this unexpected behavior:

Im using the default parameter file with modification to the scale: I 
changed the scaling to 4 4 and ran the registration.

The warped output image shows not the rescaled image, but one quarter of 
the origanal image (lower left).

Is this a problem caused by retrieving the warped output image, or what 
could be the reason for the failed scaling?

Regards,

Felix



% ---------------------------------------------------------
1 % Number of levels in the multi-res pyramid (1 = single-res)
1 % Highest level to use in the pyramid
4 4% Scaling at lowest level of pyramid
4 4 % Number of pixels per element
1.e4 % Elasticity (E)
1.e4 % Density x capacity (RhoC)
1 % Image energy scaling (gamma) - sets gradient step size
2 % NumberOfIntegrationPoints
1 % WidthOfMetricRegion
20 % MaximumIterations
% -------------------------------
% Parameters for the registration
% -------------------------------
0 0.99 % Similarity metric (0=mean sq, 1 = ncc, 2=pattern int, 3=MI, 
5=demons)
1.0 % Alpha
0 % DescentDirection (1 = max, 0 = min)
0 % DoLineSearch (0=never, 1=always, 2=if needed)
1.e1 % TimeStep
0.5 % Landmark variance
0 % Employ regridding / enforce diffeomorphism ( >= 1 -> true)
% ----------------------------------
% Information about the image inputs
% ----------------------------------
1800 % Nx (image x dimension)
1500 % Ny (image y dimension)
0 % Nz (image z dimension - not used if 2D)
../../Insight/Examples/Data/RatLungSlice1.mha % ReferenceFileName
../../Insight/Examples/Data/RatLungSlice2.mha % TargetFileName
% -------------------------------------------------------------------
% The actions below depend on the values of the flags preceding them.
% For example, to write out the displacement fields, you have to set
% the value of WriteDisplacementField to 1.
% -------------------------------------------------------------------
0 % UseLandmarks? - read the file name below if this is true
- % LandmarkFileName
./RatLung_result % ResultsFileName (prefix only)
1 % WriteDisplacementField?
./RatLung_disp % DisplacementsFileName (prefix only)
0 % ReadMeshFile?
- % MeshFileName   
END   

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