[vtkusers] procrustes alignment in similarity mode

[Leon Chen]

Hi all,


I have some corresponding landmarks and try to use procrustes filter
to align them. in rigidbody mode, the result seems right, but when I
use the similarity, which allow the scaling during transformation, all
of these points converge into one point.

It seems correct, of course the distance between these landmarks are
minimal at this moment... but ... it is so weird! In some paper they
showed it should not work like such situation...

What confuse me is that,  I tried to transform the objects (where the
landmarks are sticked) with the vtkLandmarkTransform whose destination
is the result of the procrustes filter, which is a single point! and
it worked! these object goes together but not shrink to a point again,
(rigid mode in landmark trans, if use similarity mode, they are really
shrinked...)

So my question is what is the transformation between the result from
procrustes and original position of these landmark points? and how do
they successfully transform the object together?


It annoys me for a long time, hope some one can give a talk. thank you
very much.
-- 
Leon Chen,
Imperial College, London

MSN: shineofleo at hotmail.com