Re: Removing Ring Artefacts

Posted by Jon Harman-3 on Oct 01, 2008; 10:14pm
URL: http://imagej.273.s1.nabble.com/Removing-Ring-Artefacts-tp3694905p3694910.html

Hi,

If your rings are concentric around the center of the CT system
(isocenter) then they are due to poor calibrations.  In 3rd generation
CT scanners the detectors and source rotate around the isocenter.  If a
detector is poorly calibrated the rays from the source to that detector
will be incorrect.  Those rays always pass at a constant distance from
the isocenter.  There will be a "ring" at that distance.

Jon


Sarah Martin wrote:

> Hello All,
>
> I am currently working on X-Ray CT images of soil within plastic columns
> (which have been spilt in half with mesh). See the attached image for an
> example. I am having problems removing the ring artefacts present within my
> images that will effect the analysis of pore spaces present within these
> soil columns. I have checked the archives of this mailing group and the
> plugins page for ImageJ and cannot find any evident solution to the ring
> artefact problem. I know that this is a common problem, so I hope that there
> is a solution out there someone which I have simply missed on my research.
>
> Any help you can offer will be appreciated very much.
>
> Thanks,
> Sarah
>
> http://n2.nabble.com/file/n1131486/Slice0005.jpg