<br><br>Hi Motes:<br><br><br> A Rigid Transforms is not<br> just an Affine centered Transform.<br><br><br>1) A Rigid Transform supports:<br> Translations and Rotations<br><br>2) An Affine Transform supports:<br>
Translations, Rotations, Scaling and Shearing.<br><br><br>In ITK, both the Rigid and Affine transforms are "centered".<br>Which means that you can specify what point of space should<br>be used as the center of rotations.<br>
<br><br>Yes, there is something unique that is accomplished by using<br>a Rigid Transform:<br><br><br> Managing Translations and Rotations, by only optimizing<br> in an space of Six dimensions, instead of the space of <br>
12 dimensions where you have to optimize an Affine Transform.<br> (this for the case of 3D images).<br><br><br><br> Regards,<br><br><br> Luis<br><br><br>--------------------------------------------------------------------------------------------<br>
<div class="gmail_quote">On Sun, Jul 12, 2009 at 3:14 PM, motes motes <span dir="ltr"><<a href="mailto:mort.motes@gmail.com">mort.motes@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
In the itkSoftwareGuide an examples is walked through using a RigidTransform. But is a RigidTransform not just a centered AffineTransform? I am a bit confused that a RigidTransform exists, as I understand rigid and non-rigid are concepts that includes transforms. Something like:<br>
<br>Rigid:<br> - Translation<br> - Affine<br><br>Non-Rigid<br> - BsplineDeformableTransform<br><br><br>Or are there something unique about a RigidTransform that is not accomplished using eg. translation or Affine transforms?<br>
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