[Insight-users] deformableregistration 4 & 6 error

[Luis Ibanez]

Hi Powerhouseofexcellence,


Dr. Lydia Ng, who is more familiar with Deformable Registration
using BSplines looked at the problem that you reported and found
that the vnl_lbfgs does not behave properly when it is initialized
close to the optimal value. The optimizer is terminating prematurely
and fails to initialize the vector of parameters that it returns.
The vector of parameters is therefore of zero size and results in
a size mismatch with the expected number of parameters. This final
condition is what is being flagged by the Exception.

Lydia created a variant of the DeformableRegistration4 example, by
replacing the vnl_lbfgs optimizer with the itkLBFGSBOptimizer. This
new variant has been committed as

        Insight/Examples/Registration/
                  DeformableRegistration7.cxx

you will have to update your CVS checkout, in order to get this new
example.  The example is already configured for 3D images, you can
adapt this to the dimension of your images, in line 127.


Please let us know if you have further questions,


    Thanks


      Luis




----------------------------------------------------------------------
- - wrote:
> Hi all,
> 
> Going back to the mail about deformableregistration 4 & 6 and the error:
> 
> I   NFN    FUNC        GNORM       STEPLENGTH
> IFLAG= -1. LINE SEARCH FAILED. SEE DOCUMENTATION OF ROUTINE MCSRCH ERROR RETURN
> OF LINE SEARCH: INFO=3 POSSIBLE CAUSES: FUNCTION OR GRADIENT ARE 
> INCORRECT OR INCORRECT TOLERANCESvnl_lbfgs: ** EEEK **
> 
> What causes this error? I am registering a dataset using
> deformableregistration4, it gets through a significant portion of the
> dataset but fails on certain images, I cannot tell why. The try/catch
> statement which launches registration gives the error:
> 
> itk::ExceptionObject (0012F1B4)
> Location: "Unknown" 
> File: c:\insighttoolkit-1.8.0\code\common\itkBSplineDeformableTransform.txx
> Line: 232
> Description: itk::ERROR: BSplineDeformableTransform(01125E20):
> Mismatched between parameters size and region size
> 
> Though I am printing out all the parameters of the transform, and they
> are no different from the previous iterations.. any info would be
> appreciated, thanks!
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users
> 
>