[Insight-users] [Community] Demons Deformable Registration and Paraview

[Matt McCormick]

Hi Tim,

On Sat, Dec 7, 2013 at 11:36 PM, Tim Bhatnagar <tim.bhatnagar at gmail.com> wrote:
> Hey Matt,
>
> Sorry to re-visit this specific email... in your message, you said:
>
> "The displacement fields output of ITK's deformable image registration
> represent the displacement of a point in the FixedImage to a point in
> the MovingImage.  Therefore overlaying the displacement field vector
> glyphs on the FixedImage should give the correct visualization.  The
> start of the arrow sits on its location in the input FixedImage, and
> the tip of the arrow glyphs are directed towards where a given pixel
> in the FixedImage will move to in the MovingImage."
>
> However, in the Demons examples that are built with the ITK package, an
> 'output' image from the registration is produced by passing the movingImage
> into the WarpImageFilter, and utilizing the newly created deformation field.
> This makes it seem like the deformation field actually takes the movingImage
> form into the fixedImage form, not the other way around.

Yes, it is true that the WarpImageFilter takes the movingImage and
transforms it to the fixedImage space.  Different perspectives could
be taken on what is moving or how it is moving, but all of the above
is correct.

Hope this helps,
Matt