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<p>Dear VTK users list:</p>
<p>I am reporting that the issue can be fixed by calling
SeparateWindowLevelOperationOff() on the mapper.</p>
<p>This solution was learned from an off-line conversation with
David Gobbi. The conversation was off-line as I could not provide
publicly sharable code, due to privacy considerations related to
medical data-sets.</p>
<p>Best Regards,</p>
<p>Andrea<br>
</p>
<br>
<div class="moz-cite-prefix">On 5/3/2018 11:54 PM, David Gobbi
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CANwS1=H==1f_sohwqFF56WAHqbeLTygE4UpGOy2sO1gVQvTrWA@mail.gmail.com">
<div dir="ltr">
<div>Hi Andrea,</div>
<div><br>
</div>
<div>I've tried reproducing your problem with CTs on my own
system, but so far I haven't seen the grey border.</div>
<div><br>
</div>
<div>Can you show me all of the settings that you use with
vtkImageResliceMapper and also all the settings for the
vtkImageProperty?</div>
<div><br>
</div>
<div>Also, can you tell me what version of VTK you are using?
And whether you're using the OpenGL backend or the OpenGL2
backend?</div>
<div><br>
</div>
<div>And what your are using to read the DICOM images into your
program (ITK, vtkDICOMImageReader, vtk-dicom, GDCM, etc)?</div>
<div><br>
</div>
<div> - David</div>
<div><br>
</div>
<br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, May 3, 2018 at 3:14 PM,
Andrea Borsic <span dir="ltr"><<a
href="mailto:aborsic@ne-scientific.com" target="_blank"
moz-do-not-send="true">aborsic@ne-scientific.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> Hi,<br>
<br>
I have a question about the use of the vtkImageReslice
mapper.<br>
<br>
In setting up a VTK pipeline for displaying CT image
slices we used previously a vtkImageReslice followed by
a vtkImageMapToColors. We have recently switched to
using a vtkImageResliceMapper instead of the two
previous classes, but we are experiencing an issue.<br>
<br>
When using vtkImageReslice the method
SetBackgroundLevel() was called with a value of -1000
which mapped pixels falling outside the sampled CT
volume to a black pixel on screen, given the LUT in use.<br>
<br>
In vtkImageResliceMapper the conversion from CT scalar
values to screen colors is performed internally and we
have tried playing with BackgroundOn() and with
SetBackingColor of a vtkImagePorperty is passed to the
vtkImageResliceMapper, but we are not able to get rid of
a thin gray border that at times shows around the image
as shown in the screenshot below ....<br>
<br>
<img src="cid:part2.65752F8F.56B7DC13@ne-scientific.com"
alt="" class=""><br>
<br>
Additionally, when the slicing plane is set at the very
beginning of the volume or at the very end, the output
is a slice which is completely gray.<br>
<br>
I suspect that pixel values for sampling locations that
fall outside of the CT image volume are set to a default
value which results in the gray pixels.<br>
<br>
Can anyone please advise on how to control such value -
so that gray borders could be eliminated?<br>
<br>
Thanks in advance for any suggestion,<br>
<br>
Best Regards,<br>
<br>
Andrea<br>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
++++++++++++++++++++++++++++++++++++++
Andrea Borsic Ph.D.
Founder & CEO - NE Scientific LLC
web: <a class="moz-txt-link-freetext" href="http://www.ne-scientific.com/">http://www.ne-scientific.com/</a>
twitter: <a class="moz-txt-link-freetext" href="https://twitter.com/NE_Scientific">https://twitter.com/NE_Scientific</a>
phone: +1 603 676 7450</pre>
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