[Insight-users] how to calculate displacement from B-Spline parameters

[M.Staring at lumc.nl]

Hi Pinpress,

Then the code seems to be ok. Also to me the deformation fields seems
not to correspond to expectation. Other than a problem with
visualisation I'm clueless.

Marius

> -----Original Message-----
> From: insight-users-bounces at itk.org 
> [mailto:insight-users-bounces at itk.org] On Behalf Of pinpress
> Sent: Wednesday, October 29, 2008 6:31 PM
> To: insight-users at itk.org
> Subject: Re: [Insight-users] how to calculate displacement 
> from B-Spline parameters
> 
> 
> Hi Marius,
> 
> The code is exactly the registration example program
> DeformableRegistration15.cxx -- I only modified the # of 
> iterations. I also
> checked the code, and found the following lines:
> 
>   bsplineTransformCoarse->SetBulkTransform( affineTransform );
>   bsplineTransformFine->SetBulkTransform( affineTransform );
> 
> Therefore, I think the bulk transformation was indeed set properly.?
> 
> Also, I am attaching two larger PNG files, hope it enhances 
> visualization
> (sorry for the negligence earlier). 
> 
> http://www.nabble.com/file/p20231967/output_Affine_BS.png
> output_Affine_BS.png 
> http://www.nabble.com/file/p20231967/output_LS.png output_LS.png 
> 
> Would it be possible that I post the fixed and moving images 
> here? They are
> in Analyze format. Again, the registration code is exactly the same as
> DeformableRegistration15.cxx (from ITK version 3.8).
> 
> Thanks very much!
> 
> Pinpress
> 
> 
> 
> 
> Hi Pinpress,
> 
> when you do the affine + B-spline registration you have to set the
> affine result in the bulk transform of the B-spline. You have 
> to do this
> also when you compute the displacement field. If you forget to do that
> than you will only compute the displacement of the B-spline 
> part. I can
> imagine that this part is almost zero, since the match between the
> larger and smaller circle can be captured by an affine transformation
> only. 
> 
> Can you check that you did set the affine transform in the 
> bulktransform
> of the B-spline?
> 
> I find it hard to judge the images you uploaded. Can you easily
> construct images where the deformation field is evaluated a coarser
> grid, with larger arrows?
> 
> The error seems to be a bug in your code somewhere. If you post your
> code we may be able to track it down.
> 
> Marius
> 
> 
> -- 
> View this message in context: 
> http://www.nabble.com/how-to-calculate-displacement-from-B-Spl
> ine-parameters-tp20220125p20231967.html
> Sent from the ITK - Users mailing list archive at Nabble.com.
> 
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users
> 
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com 
> Version: 8.0.175 / Virus Database: 270.8.5/1755 - Release 
> Date: 10/29/2008 5:27 PM
>