[Insight-users] Transform

[Luis Ibanez]

Hi Pandu,

This MultiResMIRegistration application uses a

          QuaternionRigidTransform

for performing the registration. The presence of
the AffineTransform is required for converting
the QuaternionRigidTransform into an Affine
transform and returning it for being used elsewhere.

An Affine transform can represent a rigid transform
without any lose of precision. In practice you can
use the Affine transform as a 'generic' transform
that can internally represt

     - Rotation transforms
     - Scaling transforms
     - Translation transforms
     - Rigid transforms
     - Similarity transforms
     - Shearing transforms
     - Reflection transforms

In this way, no matter which one of the above transforms
in actually used for performing the registration, you could
always return the results represented in an Affine transform.


No reason to worry,
Just continue enjoying your reading of the code.


Please let us know if you have further questions.



   Thanks


     Luis


-----------------------
Pandu Jugnu wrote:

> Hi Luis
> 
> I was going over the code for MultiResMIRegistration
> application. I read in the guide that this application
> uses "QuaternionRigidTransform" but I noticed the
> presence of "Affine Transform" in the code too. 
> Can you put some light on this as of why are we using
> the Affine transform in this example.
> 
> Thanks in advance.
> Pandu
> 
> 
>