[Insight-users] Interpretation of the values in the parameters array - non-rigid image registration?

[Luis Ibanez]

Hi Motes,

Yes, your interpretation of the parameters is correct.

The values that the BSpline grid is interpolating are actually the
displacements of points located at the node grid coordinates.

(The link to your PDF file didn't work for me...)

You are right in that specifying a value in the parameters array
is equivalent to defining one of the components (X or Y) of a
displacement.

This is explained in the Tutorial on deformable registration:

http://www.na-mic.org/Wiki/images/0/06/Insight-DeformableRegistration-BSplines.ppt



      Regards,


             Luis


----------------------------------------------------------------------------------
On Tue, Oct 27, 2009 at 5:48 PM, motes motes <mort.motes at gmail.com> wrote:
> When doing non-rigid 2D image registration using the
> BSplineDeformableTransform the parameters array contains the
> components of the deformation vectors in the following order:
>
>                              x1,x2,..., xN,  y1,y2,...,yN,
>
> But could those parameters not be interpreted as offsets for the
> location of the control points in a "classic" free form deformation?
>
> In the below figure the end points of the final deformation vectors
> actually corresponds to the final location of the control points in a
> 2D free form deformation:
>
> http://img163.imageshack.us/i/deformationfield.pdf/
>
> In that context specifying a value in the parameters array actually
> just corresponds to specifying an offset to the location of a control
> point in the regular grid in a free form deformation.
>
> Does this make sense?
> _____________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Kitware offers ITK Training Courses, for more information visit:
> http://www.kitware.com/products/protraining.html
>
> Please keep messages on-topic and check the ITK FAQ at:
> http://www.itk.org/Wiki/ITK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.itk.org/mailman/listinfo/insight-users
>