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<p>Hi Simon,</p>
<p>I will clean my code and submit today or Monday then.</p>
<p>best regards,</p>
<p>V.<br>
</p>
<div class="moz-cite-prefix">On 23.04.20 18:13, Simon Rit wrote:<br>
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cite="mid:CAF0oig2UM9hHbZeT3_wqfuE6poyqFpnyxMyxQ4-qrEEKi9dQHA@mail.gmail.com">
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<div dir="ltr">Thanks for the update. It's not a bad idea to
include this in the projections reader but ideally, it should
calculate the permutation parameter automatically from the
geometry. If it's optional, it's not a bad idea to have it in
the projections reader pipeline, don't hesitate to submit if you
have a clean PR.<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Thu, Apr 23, 2020 at 3:56
PM vincent <<a href="mailto:vl@xris.eu" target="_blank"
moz-do-not-send="true">vl@xris.eu</a>> wrote:<br>
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0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p>Hi,</p>
<p>just to bring some closure to that problem..</p>
<p>I didn't manage to adapt the ramp filter, so I instead
modified rtkProjectionsReader to include an Orientation
parameter that sets the right coefficients for an
itkPermuteAxis filter.</p>
<p>I don't think it is worthy to be included in the official
source, but I am happy to share if someone requires it.</p>
<p>Best regards,</p>
<p>Vincent<br>
</p>
<div>On 15.04.20 20:13, Simon Rit wrote:<br>
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<div>Hi Vincent,</div>
<div>Everything you did is correct but rtkfdk always
applies the ramp filter along the first dimension and
does not check if this corresponds to the direction
orthogonal to the rotation axis. For your case, it is
probably not so difficult to adapt the code. When
there is a small rotation, it is debatable whether one
should ignore the rotation for the ramp filter,
resample the image, or recalculate the filter in 2D
(see our recent publication <a
href="https://doi.org/10.1088/1361-6560/ab7875"
target="_blank" moz-do-not-send="true">here</a>
which has not been implemented in RTK). I have opened
an <a
href="https://github.com/SimonRit/RTK/issues/335"
target="_blank" moz-do-not-send="true">issue on
github</a>, hopefully we'll find time to fix this in
the future (at least raise an exception above a
parametrable rotation threshold).<br>
</div>
<div>Best regards,</div>
<div>Simon<br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, Apr 15, 2020
at 7:00 PM vincent <<a href="mailto:vl@xris.eu"
target="_blank" moz-do-not-send="true">vl@xris.eu</a>>
wrote:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px
0px 0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">Hi RTK community,<br>
<br>
I hope everyone is doing well in those hard times.<br>
<br>
I have a panel that is rotated by 90° on the CT
system. I used to <br>
rotate the images back in the right orientation before
building the <br>
sinogram with rtkprojections, but then I thought I
might give a try at <br>
the "newdirection" option. Using the matrix [0 1 0 ;
1 0 0 ; 0 0 1] <br>
gives the expected results. So far so good. But when
I try to <br>
reconstruct the latter with the same geometric
parameters than for the <br>
pre-rotated projections, I obtain a very blurry result
(vs a sharp one <br>
in the first case). I am obviously missing something,
and I would <br>
suspect I am not giving the right information to the
rtkfdk <br>
application. So far, here is what I have tried:<br>
<br>
-keep the projections in the initial orientation, but
give the <br>
"newdirection" option to the rtkfdk application,<br>
<br>
-specify the "newdirection" in both rtkprojections and
rtkfdk,<br>
<br>
-turn to you for advice !<br>
<br>
I thank you very much in advance for any help you
might be able to give.<br>
<br>
Best regards,<br>
<br>
Vincent<br>
<br>
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