<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
I wrote it out with vtkUnstructuredGridWriter and loaded it up in
Paraview. Showing it there with a 'Points' or '3D Glyphs'
representation shows only vertices on the external surface of the
specified region.<br>
<br>
(Python) code I used to generate:<br>
<br>
tf = vtk.vtkThreshold()<br>
tf.SetInput(img)<br>
tf.ThresholdBetween(1.5,2.5)<br>
tf.Update()<br>
op = tf.GetOutput()<br>
<br>
writer = vtk.vtkUnstructuredGridWriter()<br>
writer.SetFileName('thresh.vtk')<br>
writer.SetInput(op)<br>
writer.Write()<br>
<br>
Andrew<br>
<br>
<div class="moz-cite-prefix">On 17/11/14 17:40, David Gobbi wrote:<br>
</div>
<blockquote
cite="mid:CANwS1=H=ZMiyA2XbPmQHNgr8uQBoRFLeH8ZnjVdE4BvTEGUn8g@mail.gmail.com"
type="cite">
<div dir="ltr">Hi Andrew,
<div><br>
</div>
<div>It should export all the points in the volume, as long as
they are within the applied thresholds. What is your evidence
that it's only exporting the boundary?</div>
<div><br>
</div>
<div> - David</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Nov 17, 2014 at 9:34 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">
<div bgcolor="#FFFFFF" text="#000000"> 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
<div>
<div class="h5"><br>
<br>
<div>On 17/11/14 17:16, David Gobbi wrote:<br>
</div>
<blockquote 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>
</div>
</div>
</div>
</div>
</blockquote>
<br>
</div>
</div>
<span class="HOEnZb"><font color="#888888">
<div>-- <br>
<hr> <b>Andrew Crozier</b><br>
<a moz-do-not-send="true"
href="mailto:andrew.crozier@medunigraz.at"
target="_blank">andrew.crozier@medunigraz.at</a><br>
<br>
Postdoctoral Researcher<br>
Institute for Biophysics<br>
Medical University of Graz</div>
</font></span></div>
</blockquote>
</div>
<br>
</div>
</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>
</body>
</html>