[Rtk-users] Conjugate Gradient Artefact

[Simon Rit]

Hi,
Probably an offset detector artefact. Look at this conversation:
http://public.kitware.com/pipermail/rtk-users/2015-March/000713.html
Maybe try one of the algorithms that properly uses the offset detector
filter? For the FOV, the option --displaced will provide the full FOV.
I hope this helps,
Simon

On Thu, May 7, 2015 at 1:40 PM, Jonathan Mason <j.mason at ed.ac.uk> wrote:

> Hello RTK users,
>
> I have been using RTK for a couple of weeks now, and really like the
> software. The extensive number of tools available is really impressive
> and helpful, so thanks!
>
> I have been experiencing an cylindrical artefact in using conjugate
> gradient reconstruction — illustrated in the attached images along with
> FDK with no artefact — of which I am unsure of its origin. The data is a
> scan of a thorax phantom from a Varian on-board imager. At first I
> suspected it was due to the specimen extending beyond the reconstruction
> volume, but extending this unfortunately did not help. Something else I
> have noticed is that the FOV filter isolates just this pale cylindrical
> artefact around the centre of rotation.
>
> Do you know of the cause of this effect, or how it could be remedied?
>
> Best wishes,
>
> Jonathan
>
> --
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
>
>
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