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Hi David,<br>
<br>
Thanks for the suggestion. I looked at the vtkThreshold filer,
however it appears to export the boundary of the thresholded volume,
whereas I require all points inside the volume. Have you any idea of
how to achieve that?<br>
<br>
BW,<br>
Andrew<br>
<br>
<div class="moz-cite-prefix">On 17/11/14 17:16, David Gobbi wrote:<br>
</div>
<blockquote
cite="mid:CANwS1=G-R9G+JCpsA8H1NSRWMTEMrWSNTvN4=O=_F21HMko5bA@mail.gmail.com"
type="cite">
<div dir="ltr">Hi Andrew,
<div><br>
</div>
<div>The vtkThreshold filter will extract only the cells with
the desired</div>
<div>scalar values, and will output them as an unstructured
grid. It</div>
<div>isn't exactly what you want because it extracts cells,
rather than</div>
<div>points, but it might be worth a shot.</div>
<div><br>
</div>
<div> - David</div>
<div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Nov 17, 2014 at 8:28 AM,
Andrew Crozier <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:andrew.crozier@medunigraz.at"
target="_blank">andrew.crozier@medunigraz.at</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
I am trying to evaluate the principal components of a
strucutre in a 3D volume image, to determine its spatial
alignment for use in an automatic processing pipeline.<br>
<br>
The input is a vtkImageData, with multiple integer
values (say, 0, 1, 2 and 3), and I want to perform PCA
on the positions of all voxels with value 2, for
example.<br>
<br>
I have looked at vtkPCAAnalysisFilter, and this requires
an input of vtkPointSet. vtkImageDataToPointSet converts
a vtkImageData to a vtkStructuredGrid, however I expect
this to include all points in the original image. At the
moment I seem to be missing some way of filtering out
the points other than those of value 2.<br>
<br>
Any help provided for this would be greatly appreciated!<br>
<br>
Best wishes,<br>
Andrew Crozier<br>
<br>
</blockquote>
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</blockquote>
<br>
<div class="moz-signature">-- <br>
<hr>
<b>Andrew Crozier</b><br>
<a class="moz-txt-link-abbreviated" href="mailto:andrew.crozier@medunigraz.at">andrew.crozier@medunigraz.at</a><br>
<br>
Postdoctoral Researcher<br>
Institute for Biophysics<br>
Medical University of Graz</div>
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