rtkBackProjectionImageFilter.h

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/*=========================================================================
 *
 *  Copyright RTK Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/

#ifndef rtkBackProjectionImageFilter_h
#define rtkBackProjectionImageFilter_h

#include "rtkConfiguration.h"

#include <itkInPlaceImageFilter.h>
#include <itkConceptChecking.h>

#include "rtkThreeDCircularProjectionGeometry.h"

#include <type_traits>
#include <typeinfo>

namespace rtk
{

template <class TInputImage, class TOutputImage>
class ITK_TEMPLATE_EXPORT BackProjectionImageFilter : public itk::InPlaceImageFilter<TInputImage, TOutputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(BackProjectionImageFilter);

  using Self = BackProjectionImageFilter;
  using Superclass = itk::ImageToImageFilter<TInputImage, TOutputImage>;
  using Pointer = itk::SmartPointer<Self>;
  using ConstPointer = itk::SmartPointer<const Self>;
  using InputPixelType = typename TInputImage::PixelType;
  using InternalInputPixelType = typename TInputImage::InternalPixelType;
  using OutputImageRegionType = typename TOutputImage::RegionType;

  using GeometryType = rtk::ThreeDCircularProjectionGeometry;
  using GeometryConstPointer = typename GeometryType::ConstPointer;
  using ProjectionMatrixType = typename GeometryType::MatrixType;
  using ProjectionImageType = itk::Image<InputPixelType, TInputImage::ImageDimension - 1>;
  using ProjectionImagePointer = typename ProjectionImageType::Pointer;

  itkNewMacro(Self);

#ifdef itkOverrideGetNameOfClassMacro
  itkOverrideGetNameOfClassMacro(BackProjectionImageFilter);
#else
  itkTypeMacro(BackProjectionImageFilter, itk::ImageToImageFilter);
#endif


  itkGetConstObjectMacro(Geometry, GeometryType);
  itkSetConstObjectMacro(Geometry, GeometryType);

  itkGetMacro(Transpose, bool);
  itkSetMacro(Transpose, bool);

protected:
  BackProjectionImageFilter()
    : m_Geometry(nullptr)
  {
    this->SetNumberOfRequiredInputs(2);
    this->SetInPlace(true);
  };
  ~BackProjectionImageFilter() override = default;

  void
  VerifyPreconditions() ITKv5_CONST override;

  void
  GenerateInputRequestedRegion() override;

  void
  BeforeThreadedGenerateData() override;

  void
  DynamicThreadedGenerateData(const OutputImageRegionType & outputRegionForThread) override;

  virtual void
  CylindricalDetectorCenteredOnSourceBackprojection(
    const OutputImageRegionType &                                                         region,
    const ProjectionMatrixType &                                                          volIndexToProjPP,
    const itk::Matrix<double, TInputImage::ImageDimension, TInputImage::ImageDimension> & projPPToProjIndex,
    const ProjectionImagePointer                                                          projection);

  virtual void
  OptimizedBackprojectionX(const OutputImageRegionType & region,
                           const ProjectionMatrixType &  matrix,
                           const ProjectionImagePointer  projection);

  virtual void
  OptimizedBackprojectionY(const OutputImageRegionType & region,
                           const ProjectionMatrixType &  matrix,
                           const ProjectionImagePointer  projection);

  void
  VerifyInputInformation() const override
  {}

  template <class TProjectionImage>
  typename TProjectionImage::Pointer
  GetProjection(const unsigned int iProj);

  ProjectionMatrixType
  GetIndexToIndexProjectionMatrix(const unsigned int iProj);

  ProjectionMatrixType
  GetVolumeIndexToProjectionPhysicalPointMatrix(const unsigned int iProj);

  itk::Matrix<double, TInputImage::ImageDimension, TInputImage::ImageDimension>
  GetProjectionPhysicalPointToProjectionIndexMatrix(const unsigned int iProj);

  GeometryConstPointer m_Geometry;

private:
  bool m_Transpose{ false };
};

} // end namespace rtk

#ifndef ITK_MANUAL_INSTANTIATION
#  include "rtkBackProjectionImageFilter.hxx"
#endif

#endif