[Insight-users] LandmarkWarping2.cxx artifact

[Luis Ibanez]

Hi Sara,

The planes that you are seeing in the borders of the image
are caused when the deformation is such that points of the
image are mapped outside of the domain of the input image.

In such cases, the itkWarpImageFilter by default sets those
pixels to a zero value.  If the background value of your image
is not zero, then an artificial boundary is created in those
regions.


You can fix this, by calling the method:

         wrapper->SetEdgePaddingValue( VV );

where VV should be a value equal to the background
of your image.

For example,
in a CT scan you probably want to set VV
to the value:    -1024.


   Regards,


        Luis


--------------------------------------------------------------------------------------
On Thu, Apr 29, 2010 at 6:15 PM, Sara Rolfe <smrolfe at u.washington.edu> wrote:
> Hello,
>
> I am testing DeformableRegistration7.cxx and would like to generate my own
> example data.  I have a 3D image and would like to warp it using landmark
> warping.  I am using the example LandmarkWarping2.cxx to do this.  My
> problem is that when I warp the image I get a result that has a plane on one
> or more edges of the image.  When I use a landmark file that has no
> difference between the original and transformed points, I get no error in
> the output.   I am using the same image for the moving and fixed image since
> I assume they should stay in the same space.
>
> Please let me know if you have any idea what might cause artifacts in the
> output of LandmarkWarping2.cxx.
>
> Thanks,
>
> Sara
>
>
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