[Insight-users] help in choosing right deformable registration algorithms

[Ryan Guan]

Thanks Vivien!
That's right, the 'deformation' in this case is actually the translation of the lower ball, and I think that both algorithms caught this since the there is no much vectors around the upper ball. 
I actually also tried Demons and BSpline with another phantom, and the motion is closer to a local deformation,
Demons:
http://dl.dropbox.com/u/1906263/squash_demons.gif
B-Spline:
http://dl.dropbox.com/u/1906263/squash_bspline.gif

While when I look at them now, I start to feel that maybe BSpline got the motion right, will try to assess the accuracy.
For Demons, it's not completely unacceptable for the single ball (http://dl.dropbox.com/u/1906263/squash_demons.gif); but for the translation motion, it just couldn't work it out (http://dl.dropbox.com/u/1906263/golf_demons.gif). Is it because of the nature of Demons that prevents it from working for translation?

Thanks a lot for your help!
On 10/16/2011 07:36 PM, Ryan Guan wrote:
>Dear ITK Users,  Hi Ryan, >I am new to DIR world and I need to work out the best DVFs for my >'deformed' phantom images. >I tried Demons and B-Spline as in DeformableRegistration2 and >DeformableRegistration7, but neither of them seem to be very good. The >results can be downloaded from my dropbox: >Demons: >http://dl.dropbox.com/u/1906263/golf_demons.gif >B-Spline: >http://dl.dropbox.com/u/1906263/golf_bspline.gif >>The B-Spline ones look more reasonable but still with quite obvious >errors at the region where there is no deformation. I guess there might >be something to do before deformable registration could be helpful or >there might be better algorithms for this case? Your suggestions will be >appreciated VERY MUCH!  In your image you have a background which is not moving. It is in 
contradiction with the image registration that tries to find a smooth 
vector field on the whole image. In your case your transformation is 
locally a translation so you should try to find a translation on a 
masked image that isolate your object from your background. >Another question regarding visualizing vector fields in Paraview: it >seems that Paraview display PNG (images) and VTK (vector field, after >'scalars_X*iHat+scalars_Y*jHat' and glyph) in different Y orientations. >I haven't figured out how to correctly overlay them, but just tried to >flip and shift the vector field in Paraview, so the vector field in the >above results might not be quite aligned with the images. Will also >appreciate if you can help to let me know the best&correct way to >visualize the vector fields!  I don't know how Paraview work but for vertor field visualisation I use 
VV (http://www.creatis.insa-lyon.fr/rio/vv) >Thanks a lot for any inputs! >>Ryan  -- 
Vivien Delmon
PhD student at CREATIS, Lyon
Supported by ANRT and ELEKTA
http://www.creatis.insa-lyon.fr/rio 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20111019/20dc7c93/attachment.htm>