[Rtk-users] use RTK to perform CBCT reconstruction of short scan

[Simon Rit]

Hi,
Thanks for the kind words Patrick. To complement Jan's answer:
- rtkparkershortscanweighting may be used to see the effect of the
Parker weighting,
- rtkfdk automatically triggers Parker weighting when it detects that
the scan is short. There is a threshold in the Parker implementation
for this, 20 degrees. See rtkParkerShortScanImageFilter.txx for more
details.
- you just have to add the option --arc to make the scan short, e.g.,
--arc=200. I have added a comment on the wiki about it:
 http://wiki.openrtk.org/index.php/RTK/Scripts/FDK
Simon

On Wed, Jan 15, 2014 at 5:03 AM, Jan Hoskovec <jean.hoskovec at gmail.com> wrote:
> Hello,
>
> rtkparkershortscanweighting is indeed for preprocessing the projection
> data. I don't think there is a tutorial for it, if none of the scripts
> mentioned on wiki.openrtk.org matches your case (you'd better re-check
> that).
>
> To generate a geometry file, you will need to run
> rtksimulatedgeometry. Typing "rtksimulatedgeometry -h" should provide
> enough information, but I suggest you read
> http://www.creatis.insa-lyon.fr/~srit/geometry.pdf should you be
> confused about the geometric conventions.
>
> The -p and -r options specify the input file(s). The tool is designed
> to be able to treat multiple files at the same time, so you specify
> the directory (-p) and a file name pattern (-r) separately. If you
> have just one file in your current working directory that you want to
> treat, then you can type "-p . -r <nameofthefile>". The -o option is
> quite straightforward, it's the name of the output image.
>
> Anyhow, all RTK command line binaries have a reasonably detailed help
> available if you launch them with the "-h" option.
>
> I hope these little hints will help you to find your way out. Don't
> worry, my first reconstruction with RTK was just about as chaotic.
>
> Regards,
>
> Jan
>
> 2014/1/15 Langechuan Liu <llgc at umich.edu>:
>> Hello,
>>
>> I am new to RTK. Thanks to the creators for building such a great toolset.
>>
>> I found information about RTK because I was trying to perform a CBCT recon
>> based on a short scan obtained from Varian OBI.
>>
>> In my specific case, I have 372 projection images (both in the original
>> Varian .hnd format, and raw projection format converted with plastimatch)
>> scanned over 220 degrees of the phantom.
>>
>> I have followed the instructions on the wiki page and successfully installed
>> RTK. However I could not find much documentation regarding the parker short
>> scan weighting tool. I did find some prompts after typing into command line:
>>
>> user at Cluster:~/RTK/RTK-bin/bin$ ./rtkparkershortscanweighting
>> ./rtkparkershortscanweighting: '--geometry' ('-g') option required
>> ./rtkparkershortscanweighting: '--path' ('-p') option required
>> ./rtkparkershortscanweighting: '--regexp' ('-r') option required
>> ./rtkparkershortscanweighting: '--output' ('-o') option required
>>
>> Judging from the name, I suppose this rtkparkershortscanweighting tool is to
>> preprocess the projection data, but I am not sure. I am also puzzled at what
>> I should specify for each of the options, especially the geometry option
>> (how should I generate the geometry file, etc). I googled but to no avail.
>>
>>
>> Could somebody direct me to a tutorial, or shed some light on the usage of
>> the command line tool?
>>
>> Thanks very much!
>>
>> Best Regards,
>> Patrick L. Liu
>>
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