[Rtk-users] Back Projection
Simon Rit
simon.rit at creatis.insa-lyon.fr
Tue Aug 30 12:05:00 UTC 2022
I can't make use of this log without the corresponding program. As far as I
can tell, it seems to run!
Simon
On Tue, Aug 30, 2022 at 1:33 PM Adarsh S Sunil <adarshto3 at gmail.com> wrote:
> Hi,
>
>
>
> End means stopping the execution when addImageFilter->Update() is
> called. It won’t return from Update().
>
>
> Cmd output when it exit the program from Update():
>
>
> D:\InsightToolkit-5.2.1\Bin\bin\Release>FirstCudaReconstruction.exe backward.mha geometry.xml
> D:\InsightToolkit-5.2.1\Data_head
>
> The directory: D:\InsightToolkit-5.2.1\Data_head
>
> Contains the following DICOM Series:
>
> 1.2.826.0.1.3680043.2.1125.1.75064541463040.2005072610175534453.11.0512512
>
>
>
> Reading:
> 1.2.826.0.1.3680043.2.1125.1.75064541463040.2005072610175534453.11.0512512
>
> Writing output image...
>
>
>
> D:\InsightToolkit-5.2.1\Bin\bin\Release>
>
>
>
>
>
> Normal output in cmd:
>
> D:\InsightToolkit-5.2.1\Bin\bin\Release>FirstCudaReconstruction.exe
> backward.mha geometry.xml D:\InsightToolkit-5.2.1\Data_head
>
> The directory: D:\InsightToolkit-5.2.1\Data_head
>
> Contains the following DICOM Series:
>
> 1.2.826.0.1.3680043.2.1125.1.75064541463040.2005072610175534453.11.0512512
>
>
>
> Reading:
> 1.2.826.0.1.3680043.2.1125.1.75064541463040.2005072610175534453.11.0512512
>
> Writing output image...
>
> Reconstructing...
>
> Writing output image...
>
> Done!
>
>
>
> D:\InsightToolkit-5.2.1\Bin\bin\Release>
>
>
>
>
>
> Thanks and regards
>
> Adarsh S S
>
> On Tue, Aug 30, 2022, 2:56 PM Simon Rit <simon.rit at creatis.insa-lyon.fr>
> wrote:
>
>> Hi,
>> How does it end?
>> Simon
>>
>> On Tue, Aug 30, 2022 at 8:43 AM Adarsh S Sunil <adarshto3 at gmail.com>
>> wrote:
>>
>>> Hi,
>>>
>>> Thanks for the reply. I tried based on the suggestion and I am able
>>> to centre the Forward Projection.
>>>
>>>
>>> Now the forward projection looks like this:
>>>
>>>
>>> [image: forward.PNG]
>>>
>>>
>>> Backward Projection looks like this:
>>>
>>> [image: backward.PNG]
>>>
>>>
>>> I tried to use the AddImageFilter in different ways like:
>>>
>>> using AddImageFilterType = itk::AddImageFilter<ImageType, ImageType,
>>> ImageType>;
>>> AddImageFilterType::Pointer addImageFilter =
>>> AddImageFilterType::New();
>>> addImageFilter->SetInput1(changeFilter->GetOutput());
>>> addImageFilter->SetInput2(ForwardProj->GetOutput());
>>> addImageFilter->Update();
>>>
>>> using AddFilterType = itk::AddImageFilter<ImageType, ImageType,
>>> ImageType>;
>>> AddFilterType::Pointer addFilter = AddFilterType::New();
>>> addFilter->SetInput1(outputImage);
>>> addFilter->SetInput2(changeFilter->GetOutput());
>>> addFilter->Update();
>>>
>>> But it is not working. When I use it, the program flow ends at
>>> AddImageFilter.
>>>
>>> What do I need to do to get the correct Backward projection? Please help.
>>>
>>> Thanks & Regards
>>> Adarsh S S
>>>
>>>
>>> On Thu, 25 Aug 2022 at 02:20, Simon Rit <simon.rit at creatis.insa-lyon.fr>
>>> wrote:
>>>
>>>> Hi,
>>>> To make air at 0, you need to add the opposite of the air value (1000
>>>> for HU) to your image, e.g. with itk::AddImageFilter.
>>>> To shift your image, you can change its origin with
>>>> itk::ChangeInformationImageFilter.
>>>> Simon
>>>>
>>>> On Mon, Aug 22, 2022 at 5:26 PM Adarsh S Sunil <adarshto3 at gmail.com>
>>>> wrote:
>>>>
>>>>> Hi Simon,
>>>>>
>>>>> Thanks for the support. I tried based on your suggestions.
>>>>>
>>>>>
>>>>>
>>>>> First I tried to align my volume to center by adjusting values in SetOrigin()
>>>>> and geometry->AddProjection(sid, sdd, 0, 0, 0, angle, 0, 0 , 0).
>>>>>
>>>>> But it only shifted the projection even I tried to change offset for
>>>>> source.
>>>>>
>>>>> Also I couldn’t find anything that shows how to make the air at 0.
>>>>>
>>>>> Could you please suggest a reference which shows how to do them both??
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Thanks and Regards
>>>>>
>>>>> Adarsh S S
>>>>>
>>>>> On Thu, Aug 18, 2022, 3:29 AM Simon Rit <
>>>>> simon.rit at creatis.insa-lyon.fr> wrote:
>>>>>
>>>>>> I ran it and the output is not completely black. But you probably
>>>>>> need to modify your projections to make the air at 0 (add -1024). You also
>>>>>> may want to center your volume, the forward projections look weird
>>>>>> currently.
>>>>>> Simon
>>>>>>
>>>>>> On Wed, Aug 17, 2022 at 8:41 AM Adarsh S Sunil <adarshto3 at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> I’m attaching my code here. I’m trying to get the
>>>>>>> Forward projection and backward projection from dicom data.
>>>>>>>
>>>>>>>
>>>>>>> CT input :
>>>>>>> https://drive.google.com/drive/folders/1Vc3HfqvfBdtviuVdbBhDQev2ZDEH7NYX?usp=sharing
>>>>>>>
>>>>>>>
>>>>>>> Usage: Run from output location on cmd as
>>>>>>>
>>>>>>> FirstCudaReconstruction.exe <outputFile.mha> <geoemtry.xml> <CT
>>>>>>> DICOM directory location>
>>>>>>>
>>>>>>>
>>>>>>> Please check it and let me know the problems in it.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Thanks and Regards
>>>>>>>
>>>>>>> Adarsh SS
>>>>>>> Thanks & Regards
>>>>>>> Adarsh S S
>>>>>>>
>>>>>>>
>>>>>>> On Tue, 16 Aug 2022 at 19:05, Simon Rit <
>>>>>>> simon.rit at creatis.insa-lyon.fr> wrote:
>>>>>>>
>>>>>>>> Hi,
>>>>>>>> Can you maybe share a complete script with an input CT? I also
>>>>>>>> don't understand what's going on but we never get a full picture of what
>>>>>>>> you're doing.
>>>>>>>> Simon
>>>>>>>>
>>>>>>>> On Tue, Aug 16, 2022 at 3:23 PM Adarsh S Sunil <adarshto3 at gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> Thank you for the answer.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> The following is the output for Forward Projection (ForwardProj->
>>>>>>>>> GetOutput()) :
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> [image: image002.png]
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> As you suggested I tried with changeFilter->GetOutput() instead
>>>>>>>>> of outputImage1 as follows:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> using BackFilter = rtk::CudaFDKConeBeamReconstructionFilter;
>>>>>>>>>
>>>>>>>>> auto BackProjFilter = BackFilter::New();
>>>>>>>>>
>>>>>>>>> // FDK reconstruction
>>>>>>>>>
>>>>>>>>> std::cout << "Reconstructing..." << std::endl;
>>>>>>>>>
>>>>>>>>> BackProjFilter->SetInput(0, changeFilter->GetOutput());
>>>>>>>>>
>>>>>>>>> BackProjFilter->SetInput(1, ForwardProj->GetOutput());
>>>>>>>>>
>>>>>>>>> BackProjFilter->SetGeometry(geometry);
>>>>>>>>>
>>>>>>>>> BackProjFilter->Update();
>>>>>>>>>
>>>>>>>>> BackProjFilter->UpdateOutputInformation();
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> // Writer
>>>>>>>>>
>>>>>>>>> std::cout << "Writing output image..." << std::endl;
>>>>>>>>>
>>>>>>>>> using WriterType = itk::ImageFileWriter<ImageType>;
>>>>>>>>>
>>>>>>>>> WriterType::Pointer writer = WriterType::New();
>>>>>>>>>
>>>>>>>>> writer->SetFileName(argv[1]);
>>>>>>>>>
>>>>>>>>> writer->SetInput(BackProjFilter->GetOutput());
>>>>>>>>>
>>>>>>>>> writer->Update();
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> But I’m still getting the output BackProjFilter->GetOutput() as a
>>>>>>>>> black image.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> [image: image004.png]
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I checked the value for changeFilter->GetOutput()and it gives the
>>>>>>>>> dicom data.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I’m using ITK version 5.2.1 and RTK version 2.0. Can you please
>>>>>>>>> help me understand why I’m not getting a back projection?
>>>>>>>>>
>>>>>>>>> Are there any extra options to set for getting the back
>>>>>>>>> projection? What do I have to do to get the correct back projection?
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Thanks and Regards
>>>>>>>>>
>>>>>>>>> Adarsh S S
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Sat, Aug 13, 2022, 10:43 AM Simon Rit <
>>>>>>>>> simon.rit at creatis.insa-lyon.fr> wrote:
>>>>>>>>>
>>>>>>>>>> Your approach is correct and there is no need to do multiple
>>>>>>>>>> files. The outputImage1 (for backprojection) should have the same
>>>>>>>>>> information as the tomography (changeFilter->GetOutput()), not the same
>>>>>>>>>> information as the projections (outputImage). Maybe that's the problem here?
>>>>>>>>>> Simon
>>>>>>>>>>
>>>>>>>>>> On Fri, Aug 12, 2022 at 2:37 PM Adarsh S Sunil <
>>>>>>>>>> adarshto3 at gmail.com> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi,
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Thanks for the reply. The outputImage passed as
>>>>>>>>>>> input to the backprojection does not have the same information as
>>>>>>>>>>> reader->GetOutput().
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> I’m writing the forwardProjection in to a single file named
>>>>>>>>>>> Forward.mha.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> rtk::ForwardProjectionImageFilter<ImageType, ImageType>::
>>>>>>>>>>> Pointer ForwardProj =
>>>>>>>>>>>
>>>>>>>>>>> rtk::CudaForwardProjectionImageFilter<ImageType, ImageType
>>>>>>>>>>> >::New();
>>>>>>>>>>>
>>>>>>>>>>> dynamic_cast<rtk::CudaForwardProjectionImageFilter<ImageType,
>>>>>>>>>>> ImageType> *>(ForwardProj.GetPointer())->SetStepSize(1);
>>>>>>>>>>>
>>>>>>>>>>> ForwardProj->SetInput(0, outputImage);
>>>>>>>>>>>
>>>>>>>>>>> ForwardProj->SetInput(1, changeFilter->GetOutput());
>>>>>>>>>>>
>>>>>>>>>>> ForwardProj->SetGeometry(geometry);
>>>>>>>>>>>
>>>>>>>>>>> ForwardProj->Update();
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> // Writer
>>>>>>>>>>>
>>>>>>>>>>> std::cout << "Writing output image..." << std::endl;
>>>>>>>>>>>
>>>>>>>>>>> using WriterType1 = itk::ImageFileWriter<ImageType>;
>>>>>>>>>>>
>>>>>>>>>>> WriterType1::Pointer writer1 = WriterType1::New();
>>>>>>>>>>>
>>>>>>>>>>> writer1->SetFileName("Forward.mha");
>>>>>>>>>>>
>>>>>>>>>>> writer1->SetInput(ForwardProj->GetOutput());
>>>>>>>>>>>
>>>>>>>>>>> writer1->Update();
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Also, I’m setting the same regions, spacing, origin etc. to
>>>>>>>>>>> forward and backward projections as follows:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> using RegionType = itk::ImageRegion<3>;
>>>>>>>>>>>
>>>>>>>>>>> ImageType::Pointer inputImage = reader->GetOutput();
>>>>>>>>>>>
>>>>>>>>>>> RegionType inputRegion =
>>>>>>>>>>> inputImage->GetLargestPossibleRegion();
>>>>>>>>>>>
>>>>>>>>>>> ImageType::Pointer outputImage = ImageType::New();
>>>>>>>>>>>
>>>>>>>>>>> ImageType::Pointer outputImage1 = ImageType::New();
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> using changeImageFilter = itk::ChangeInformationImageFilter<
>>>>>>>>>>> ImageType>;
>>>>>>>>>>>
>>>>>>>>>>> auto changeFilter = changeImageFilter::New();
>>>>>>>>>>>
>>>>>>>>>>> double rotationX = 90;
>>>>>>>>>>>
>>>>>>>>>>> itk::Versor<double> rotation;
>>>>>>>>>>>
>>>>>>>>>>> const double angleInRadians = rotationX * vnl_math::pi
>>>>>>>>>>> / 180.0;
>>>>>>>>>>>
>>>>>>>>>>> rotation.SetRotationAroundY(angleInRadians);
>>>>>>>>>>>
>>>>>>>>>>> const ImageType::DirectionType direction =
>>>>>>>>>>> inputImage->GetDirection();
>>>>>>>>>>>
>>>>>>>>>>> const ImageType::DirectionType newDirection = direction *
>>>>>>>>>>> rotation.GetMatrix();
>>>>>>>>>>>
>>>>>>>>>>> changeFilter->SetOutputDirection(newDirection);
>>>>>>>>>>>
>>>>>>>>>>> changeFilter->ChangeAll();
>>>>>>>>>>>
>>>>>>>>>>> changeFilter->SetInput(inputImage);
>>>>>>>>>>>
>>>>>>>>>>> changeFilter->UpdateOutputInformation();
>>>>>>>>>>>
>>>>>>>>>>> changeFilter->Update();
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> const unsigned int NumberOfProjectionImages = 180;
>>>>>>>>>>>
>>>>>>>>>>> ImageType::IndexType start;
>>>>>>>>>>>
>>>>>>>>>>> start[0] = inputRegion.GetIndex()[0];
>>>>>>>>>>>
>>>>>>>>>>> start[1] = inputRegion.GetIndex()[1];
>>>>>>>>>>>
>>>>>>>>>>> start[2] = inputRegion.GetIndex()[2];
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> RegionType::SizeType size;
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> size[0] = inputRegion.GetSize()[0];
>>>>>>>>>>>
>>>>>>>>>>> size[1] = inputRegion.GetSize()[1];
>>>>>>>>>>>
>>>>>>>>>>> size[2] = NumberOfProjectionImages;
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> RegionType region;
>>>>>>>>>>>
>>>>>>>>>>> region.SetSize(size);
>>>>>>>>>>>
>>>>>>>>>>> region.SetIndex(start);
>>>>>>>>>>>
>>>>>>>>>>> ImageType::SpacingType spacing;
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> spacing[0] = inputImage->GetSpacing()[0];
>>>>>>>>>>>
>>>>>>>>>>> spacing[1] = inputImage->GetSpacing()[1];
>>>>>>>>>>>
>>>>>>>>>>> spacing[2] = inputImage->GetSpacing()[2];
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> ImageType::PointType origin;
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> origin[0] = inputImage->GetOrigin()[0];
>>>>>>>>>>>
>>>>>>>>>>> origin[1] = inputImage->GetOrigin()[1];
>>>>>>>>>>>
>>>>>>>>>>> origin[2] = inputImage->GetOrigin()[2];
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> //For Forward Projection
>>>>>>>>>>>
>>>>>>>>>>> outputImage->SetRegions(region);
>>>>>>>>>>>
>>>>>>>>>>> outputImage->SetSpacing(spacing);
>>>>>>>>>>>
>>>>>>>>>>> outputImage->SetOrigin(origin);
>>>>>>>>>>>
>>>>>>>>>>> outputImage->Allocate();
>>>>>>>>>>>
>>>>>>>>>>> outputImage->FillBuffer(size[0] * size[1] * size[2]);
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> //For Backward Projection
>>>>>>>>>>>
>>>>>>>>>>> outputImage1->SetRegions(region);
>>>>>>>>>>>
>>>>>>>>>>> outputImage1->SetSpacing(spacing);
>>>>>>>>>>>
>>>>>>>>>>> outputImage1->SetOrigin(origin);
>>>>>>>>>>>
>>>>>>>>>>> outputImage1->Allocate();
>>>>>>>>>>>
>>>>>>>>>>> outputImage1->FillBuffer(size[0] * size[1] * size[2]);
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> I tried to give the output of forward projection directly. But
>>>>>>>>>>> it did not work. I was only getting a blank image.
>>>>>>>>>>>
>>>>>>>>>>> So I tried a different approach. I read somewhere that using
>>>>>>>>>>> Projection reader is better. So, I’m trying using projection readers.
>>>>>>>>>>>
>>>>>>>>>>> Then I put the Forward Projection reader (
>>>>>>>>>>> ForwardProj->GetOutput()) as the input of Backward Projection.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> using FileNamesContainer = std::vector<std::string>;
>>>>>>>>>>>
>>>>>>>>>>> FileNamesContainer fileNames =
>>>>>>>>>>> nameGenerator->GetFileNames(seriesIdentifier);
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> using ReaderType1 = rtk::ProjectionsReader<ImageType>;
>>>>>>>>>>>
>>>>>>>>>>> ReaderType1::Pointer reader1 = ReaderType1::New();
>>>>>>>>>>>
>>>>>>>>>>> reader1->SetFileNames(fileNames);
>>>>>>>>>>>
>>>>>>>>>>> reader1->Update();
>>>>>>>>>>>
>>>>>>>>>>> using BackFilter = rtk::CudaFDKConeBeamReconstructionFilter;
>>>>>>>>>>>
>>>>>>>>>>> auto BackProjFilter = BackFilter::New();
>>>>>>>>>>>
>>>>>>>>>>> // FDK reconstruction
>>>>>>>>>>>
>>>>>>>>>>> std::cout << "Reconstructing..." << std::endl;
>>>>>>>>>>>
>>>>>>>>>>> BackProjFilter->SetInput(0, outputImage1);
>>>>>>>>>>>
>>>>>>>>>>> BackProjFilter->SetInput(1, ForwardProj->GetOutput());
>>>>>>>>>>>
>>>>>>>>>>> BackProjFilter->SetGeometry(geometry);
>>>>>>>>>>>
>>>>>>>>>>> BackProjFilter->Update();
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> // Writer
>>>>>>>>>>>
>>>>>>>>>>> std::cout << "Writing output image..." << std::endl;
>>>>>>>>>>>
>>>>>>>>>>> using WriterType = itk::ImageFileWriter<ImageType>;
>>>>>>>>>>>
>>>>>>>>>>> WriterType::Pointer writer = WriterType::New();
>>>>>>>>>>>
>>>>>>>>>>> writer->SetFileName("BackImage.mha");
>>>>>>>>>>>
>>>>>>>>>>> writer->SetInput(outputImage1);
>>>>>>>>>>>
>>>>>>>>>>> writer->Update();
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Still I’m not getting any valid output.
>>>>>>>>>>>
>>>>>>>>>>> Is my approach to get backward projection from forward
>>>>>>>>>>> projection correct?
>>>>>>>>>>>
>>>>>>>>>>> Do we have to write forward and backward projections to multiple
>>>>>>>>>>> files? Then how to do it?
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Thanks and regards
>>>>>>>>>>>
>>>>>>>>>>> Adarsh S S
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Fri, Aug 12, 2022, 2:16 PM Simon Rit <
>>>>>>>>>>> simon.rit at creatis.insa-lyon.fr> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Hi,
>>>>>>>>>>>> It should work. UpdateOutputInformation is not required (it's
>>>>>>>>>>>> done by Update already). Does the outputImage passed as input to the
>>>>>>>>>>>> backprojection have the same information as reader->GetOutput()?
>>>>>>>>>>>> Simon
>>>>>>>>>>>>
>>>>>>>>>>>> On Fri, Aug 12, 2022 at 8:57 AM Adarsh S Sunil <
>>>>>>>>>>>> adarshto3 at gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> Hi all,
>>>>>>>>>>>>>
>>>>>>>>>>>>> I'm a beginner in rtk. I want to use the forward and
>>>>>>>>>>>>> backward projection in CT images. For that I defined the RTK geometry
>>>>>>>>>>>>> object and seriesIdContainer.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Then I read CT data and assign it to a reader and set it as
>>>>>>>>>>>>> inputImage.
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> * while (seriesItr != seriesUID.end())*
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> * { seriesIdentifier = seriesItr->c_str();
>>>>>>>>>>>>> seriesItr++; std::cout << "\nReading: "; std::cout <<
>>>>>>>>>>>>> seriesIdentifier << std::endl; using FileNamesContainer =
>>>>>>>>>>>>> std::vector<std::string>; FileNamesContainer fileNames =
>>>>>>>>>>>>> nameGenerator->GetFileNames(seriesIdentifier); using ImageIOType =
>>>>>>>>>>>>> itk::GDCMImageIO; auto dicomIO = ImageIOType::New();
>>>>>>>>>>>>> reader->SetImageIO(dicomIO); reader->SetFileNames(fileNames);
>>>>>>>>>>>>> reader->ForceOrthogonalDirectionOff(); // properly read CTs with gantry
>>>>>>>>>>>>> tilt TRY_AND_EXIT_ON_ITK_EXCEPTION(reader->Update()) }*
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> * using RegionType = itk::ImageRegion<3>;
>>>>>>>>>>>>> ImageType::Pointer inputImage = reader->GetOutput(); RegionType
>>>>>>>>>>>>> inputRegion = inputImage->GetLargestPossibleRegion(); ImageType::Pointer
>>>>>>>>>>>>> outputImage = ImageType::New();*
>>>>>>>>>>>>>
>>>>>>>>>>>>> Then I created Imageregion and imageFilter for outputImage.
>>>>>>>>>>>>> Then I set the regions, spacing, origin etc.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Then I get the Forward Projection like the following:
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> * rtk::ForwardProjectionImageFilter<ImageType,
>>>>>>>>>>>>> ImageType>::Pointer ForwardProj =
>>>>>>>>>>>>> rtk::CudaForwardProjectionImageFilter<ImageType, ImageType>::New();
>>>>>>>>>>>>> dynamic_cast<rtk::CudaForwardProjectionImageFilter<ImageType, ImageType>
>>>>>>>>>>>>> *>(ForwardProj.GetPointer()) ->SetStepSize( 1 ); ForwardProj->SetInput( 0,
>>>>>>>>>>>>> outputImage ); ForwardProj->SetInput( 1, changeFilter->GetOutput());
>>>>>>>>>>>>> ForwardProj->SetGeometry( geometry ); ForwardProj->Update();*
>>>>>>>>>>>>>
>>>>>>>>>>>>> Then I wrote the ForwardProj to an mha file.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Then I put the output from Forward Projection as input of Back
>>>>>>>>>>>>> Projection.
>>>>>>>>>>>>> Now I am trying to get the back projection like the following:
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> * using ReaderType1 = rtk::ProjectionsReader<ImageType>;
>>>>>>>>>>>>> ReaderType1::Pointer reader1 = ReaderType1::New(); reader1->SetFileNames(
>>>>>>>>>>>>> fileNames ); reader1->Update(); using BackFilter =
>>>>>>>>>>>>> rtk::CudaFDKConeBeamReconstructionFilter; auto BackProjFilter =
>>>>>>>>>>>>> BackFilter::New(); // FDK reconstruction BackProjFilter->SetInput( 0,
>>>>>>>>>>>>> outputImage ); BackProjFilter->SetInput( 1, reader1->GetOutput() );
>>>>>>>>>>>>> BackProjFilter->SetGeometry( geometry ); BackProjFilter->Update();
>>>>>>>>>>>>> BackProjFilter->UpdateOutputInformation();*
>>>>>>>>>>>>>
>>>>>>>>>>>>> But I'm not getting the back projection. Are there any
>>>>>>>>>>>>> additional options I have to set??
>>>>>>>>>>>>> Is there anything I have missed??
>>>>>>>>>>>>>
>>>>>>>>>>>>> Thanks & Regards
>>>>>>>>>>>>> Adarsh S S
>>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>>> Rtk-users mailing list
>>>>>>>>>>>>> Rtk-users at public.kitware.com
>>>>>>>>>>>>> https://public.kitware.com/cgi-bin/mailman/listinfo/rtk-users
>>>>>>>>>>>>>
>>>>>>>>>>>>
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