[vtkusers] problems with ICP alignement

[Jonathan.Bailleul]

"Jonathan.Bailleul" wrote:
> 
> Dear all,
> 
> I'm using ICP to align polydata of very similar shape but various
> positions and orientation. In general, this works fine for the shape I
> study, but here is a case where ICP fails!
> (http://www.greyc.ismra.fr/~bailleul/These/ICPfail-start.jpg &
> http://www.greyc.ismra.fr/~bailleul/These/ICPfail-end.jpg)
> 
> Please note that in the general case, I might also be obliged to adjust
> the scale factor of the mesh to align in order to converge to a relevant
> result: in that one, no adjustment managed to make it.
> 
> How could I do to have it work in all cases? Adjusting the initial
> orientation of the shapes (how?)?
> 
> In advance, thanks a lot for your comments


I just found a trick to help me out of my own trap, but nothing to be
proud of.
The shape to align is always the same in all my tests, and the reference
shape does not vary too much in position and orientation (since
extracted from brains that are globally aligned). Even that little
variation is enough to have the ICP unstable, but the most important
difference is in the orientation of the shape to align regarding to the
reference ones. 
So, for one case where I managed to align the shape, I replaced the mean
shape by this one with good success in other cases! 

But since this is far from satisfying (manual operations required), I'd
be glad to benefit from your suggestions.


Best regards,


-- 
-----------------------------------
Jonathan BAILLEUL, Doctorant
GREYC Image - Université de Caen 
http://www.greyc.ismra.fr/~bailleul