<div dir="ltr"><div><div><div>Hey Yago,<br><br></div>Thanks for the work you did for me!<br><br></div>For my work, it's not the actual visualization that I can't achieve.. it's not being able to know (for certain) which 'direction' my displacement field maps my data. <br>
<br></div><div>BUT, you don't seem to do any 'scaling' of your deformation field before you visualize it in Paraview.. so is it safe to say that the displacementfield.vtk file I output from my registration process, will be visualized correctly (no need to 'flip' axes, etc) in Paraview? Even knowing that for sure would definitely help!<br>
<br></div><div>Also, did you just generate a deformation field, or is it a result of a registration process?<br><br>Thanks so much!<br><br>Tim<br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Mon, Dec 9, 2013 at 8:42 AM, Yago Diez <span dir="ltr"><<a href="mailto:yagodiezdonoso@gmail.com" target="_blank">yagodiezdonoso@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><div class="gmail_quote"><div dir="ltr">Tim,<br><div><br>I did a small test visualizing 2D deformation fields in <span>paraview</span>, I used .vtk files but .mhd files should also work fine.<br>
<br>You can use <span>paraview</span> to visualize deformation fields. You have a description on how to do this in the 8.15 section of the itk guide (Visualizing Deformation fields).<br>
<br>Mainly you have to:<br><br>1) open the file with paraview<br>
2) Open a calculator with the following formula: <br>
<br>scalars_X*iHat+scalars_Y*jHat+0*kHat<br><div><br>The idea here is to
obtain a 3D vector with z component =0 and the other components the
deformation components. For 3D you probably want to represent all
components using something like (not tested!) ->
scalars_X*iHat+scalars_Y*jHat+scalars_Z*kHat<br>
<br>3) In order to visualize this, you have to use a "gliph", here you
can control the number of points that you represent and so on, you
obtain something like the "campDefDemons" attached file.<br></div><br><div class="gmail_extra"></div><div class="gmail_extra">Hope this helps<span class="HOEnZb"><font color="#888888"><span><font color="#888888"><br>
</font></span></font></span></div><span class="HOEnZb"><font color="#888888"><span><font color="#888888"><div class="gmail_extra">
Yago<br></div></font></span></font></span><div><div><div class="gmail_extra">
<br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Sun, Dec 8, 2013 at 6:07 AM, Matt McCormick <span dir="ltr"><<a href="mailto:matt.mccormick@kitware.com" target="_blank">matt.mccormick@kitware.com</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div class="h5">Hi Tim,<br>
<div><br>
On Sat, Dec 7, 2013 at 11:36 PM, Tim Bhatnagar <<a href="mailto:tim.bhatnagar@gmail.com" target="_blank">tim.bhatnagar@gmail.com</a>> wrote:<br>
> Hey Matt,<br>
><br>
> Sorry to re-visit this specific email... in your message, you said:<br>
><br>
> "The displacement fields output of ITK's deformable image registration<br>
> represent the displacement of a point in the FixedImage to a point in<br>
> the MovingImage. Therefore overlaying the displacement field vector<br>
> glyphs on the FixedImage should give the correct visualization. The<br>
> start of the arrow sits on its location in the input FixedImage, and<br>
> the tip of the arrow glyphs are directed towards where a given pixel<br>
> in the FixedImage will move to in the MovingImage."<br>
><br>
> However, in the Demons examples that are built with the ITK package, an<br>
> 'output' image from the registration is produced by passing the movingImage<br>
> into the WarpImageFilter, and utilizing the newly created deformation field.<br>
> This makes it seem like the deformation field actually takes the movingImage<br>
> form into the fixedImage form, not the other way around.<br>
<br>
</div>Yes, it is true that the WarpImageFilter takes the movingImage and<br>
transforms it to the fixedImage space. Different perspectives could<br>
be taken on what is moving or how it is moving, but all of the above<br>
is correct.<br>
<br>
Hope this helps,<br>
Matt<br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Tim Bhatnagar<br>PhD Candidate<br>Orthopaedic Injury Biomechanics Group<br>Department of Mechanical Engineering<br>University of British Columbia<br><br>Rm 5000 - 818 West 10th Ave.<br>
Vancouver, BC<br>Canada<br>V5Z 1M9<br><br>Ph: (604) 675-8845<br>Fax: (604) 675-8820<br>Web: <a href="http://oibg.mech.ubc.ca" target="_blank">oibg.mech.ubc.ca</a><br>
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