Re: Removing Ring Artefacts

Posted by Gluender-2 on Oct 01, 2008; 11:10pm
URL: http://imagej.273.s1.nabble.com/Removing-Ring-Artefacts-tp3694905p3694908.html

>Gluender-2 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
>>
>>
>>  I'm quite sure that those rings are not artefacts of CT image
>>  formation. So could you please be more specific and point us to the
>>  source of your opinion:
>>
>>  "I know that this is a common problem..."
>>
>  > Best
>  >                    Herbie
>
>Ring artifacts are common on all real world CT image systems. They
>correspond for example to defects of the detector. The artifact will be at a
>fixed position on the projections and thus form a circle (360 degrees scan)
>or half circle (180 degrees scan) on the tomographic slice. The best
>solution is to avoid these artifacts at the source or to correct on the
>projections. [...]

Thanks, this is correct but I use to assume that scientists work with
fully functional and adjusted equipment. Again an example where image
processing is to be applied to remedy problems with image
acquisition...

Best
--

                   Herbie

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