[Rtk-users] Does rtkbackprojections handle half-beam data?

[Andy Shieh]

Thanks Simon! It works great!
Merry Christmas and Happy New Year!

Andy


2012/12/27 Simon Rit <simon.rit at creatis.insa-lyon.fr>

> Hi Andy,
> Indeed, you also need to comment the update of the ramp filter:
> m_RampFilter->Update();
> This time, I tested it and it works!
> Simon
>
> On Thu, Dec 20, 2012 at 2:03 PM, Andy Shieh <hsieandy at gmail.com> wrote:
> > Hi Simon,
> >
> > Thanks. I tried disabling ramp filter in
> > rtkFDKConeBeamReconstructionFilter.txx with the new line, but then gets a
> > runtime error as this:
> >
> > ExceptionObject caught with writer->Update()
> > itk::ExceptionObject (0000000000AFE978)
> > Location: "void __cdecl itk::DataObject::PropagateRequestedRegion(void)
> > throw(cl
> > ass itk::InvalidRequestedRegionError)"
> > File: ..\..\..\Code\Common\itkDataObject.cxx
> > Line: 397
> > Description: Requested region is (at least partially) outside the largest
> > possible region.
> >
> > which I don't get if I use the original line. I tried lowering the
> > reconstructed region, but it didn't help.
> > My projection size is 1024*768, 0.388 mm in both directions. It's half
> beam
> > data, detector being displaced by 14.8 cm.
> > The reconstructed region I always use is 512*100*512, spacing being
> > 0.88,2,0.88 mm.
> >
> > Cheers,
> > Andy.
> >
> >
> >
> > 2012/12/17 Simon Rit <simon.rit at creatis.insa-lyon.fr>
> >>
> >> Hi Andy,
> >> Handling of the half-beam data (we call it displaced detector in RTK
> >> if I understand you correctly) is done on the projection level with
> >> the following filter :
> >>
> >>
> http://www.openrtk.org/Doxygen/classrtk_1_1DisplacedDetectorImageFilter.html
> >>
> >> You an check in rtkfdk.cxx how to use it.
> >>
> >> If you want to disable the ramp filter during reconstruction, a
> >> "simple" way would be to change the internal pipeline connections in
> >> rtk::FDKConeBeamReconstructionFilter. Replace in
> >> rtkFDKConeBeamReconstructionFilter.txx the line
> >>   m_BackProjectionFilter->SetInput( 1, m_RampFilter->GetOutput() );
> >> with
> >>   m_BackProjectionFilter->SetInput( 1, m_WeightFilter->GetOutput() );
> >> I hope this helps,
> >> Simon
> >>
> >>
> >> On Sat, Dec 15, 2012 at 2:44 PM, Andy Shieh <hsieandy at gmail.com> wrote:
> >> > Hi Simon,
> >> >
> >> > I've been using rtkfdk to reconstruct and noticed that it handles
> >> > half-beam
> >> > data.
> >> > In some situation, I want to use rtkbackprojections (for cases I don't
> >> > want
> >> > to include ramp filtering). Does rtkbackprojections handle half-beam
> >> > data
> >> > correctly, too? I gave it a try and it seems like rtkbackprojections
> >> > would
> >> > result in some kind of voxel accumulation in the middle, which
> probably
> >> > means it doesn't handle half-beam data correctly like rtkfdk?
> >> > If that's the case, is it possible to make rtkbackproejctions support
> >> > half-beam data in the next patch (if it's not some massive work)?
> >> > Thanks!
> >> >
> >> > Cheers,
> >> > Andy
> >
> >
>
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