rtkFFTProjectionsConvolutionImageFilter.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 rtkFFTProjectionsConvolutionImageFilter_h
#define rtkFFTProjectionsConvolutionImageFilter_h

#include <itkImageToImageFilter.h>
#include <itkConceptChecking.h>

#include "rtkConfiguration.h"
#include "rtkMacro.h"

namespace rtk
{

template <class TInputImage, class TOutputImage, class TFFTPrecision>
class ITK_TEMPLATE_EXPORT FFTProjectionsConvolutionImageFilter
  : public itk::ImageToImageFilter<TInputImage, TOutputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(FFTProjectionsConvolutionImageFilter);

  using Self = FFTProjectionsConvolutionImageFilter;
  using Superclass = itk::ImageToImageFilter<TInputImage, TOutputImage>;
  using Pointer = itk::SmartPointer<Self>;
  using ConstPointer = itk::SmartPointer<const Self>;

  using InputImageType = TInputImage;
  using OutputImageType = TOutputImage;
  using RegionType = typename InputImageType::RegionType;
  using IndexType = typename InputImageType::IndexType;
  using SizeType = typename InputImageType::SizeType;

  using FFTInputImageType = typename itk::Image<TFFTPrecision, TInputImage::ImageDimension>;
  using FFTInputImagePointer = typename FFTInputImageType::Pointer;
  using FFTOutputImageType = typename itk::Image<std::complex<TFFTPrecision>, TInputImage::ImageDimension>;
  using FFTOutputImagePointer = typename FFTOutputImageType::Pointer;
  using ZeroPadFactorsType = itk::Vector<int, 2>;

  static constexpr unsigned int ImageDimension = TOutputImage::ImageDimension;

  itkOverrideGetNameOfClassMacro(FFTProjectionsConvolutionImageFilter);

  itkGetConstMacro(GreatestPrimeFactor, int);
  itkSetMacro(GreatestPrimeFactor, int);

  itkGetConstMacro(TruncationCorrection, double);
  itkSetMacro(TruncationCorrection, double);

  itkGetConstMacro(ZeroPadFactors, ZeroPadFactorsType);
  virtual void
  SetZeroPadFactors(ZeroPadFactorsType _arg)
  {
    if (m_ZeroPadFactors != _arg)
    {
      m_ZeroPadFactors = _arg;
      m_ZeroPadFactors[0] = std::max(m_ZeroPadFactors[0], 1);
      m_ZeroPadFactors[1] = std::max(m_ZeroPadFactors[1], 1);
      m_ZeroPadFactors[0] = std::min(m_ZeroPadFactors[0], 2);
      m_ZeroPadFactors[1] = std::min(m_ZeroPadFactors[1], 2);
      this->Modified();
    }
  }

  itkConceptMacro(ImageDimensionCheck, (itk::Concept::SameDimensionOrMinusOne<Self::InputImageDimension, 3>));

protected:
  FFTProjectionsConvolutionImageFilter();
  ~FFTProjectionsConvolutionImageFilter() override = default;

  void
  GenerateInputRequestedRegion() override;

  void
  BeforeThreadedGenerateData() override;

  void
  AfterThreadedGenerateData() override;

  void
  ThreadedGenerateData(const RegionType & outputRegionForThread, ThreadIdType threadId) override;

  virtual FFTInputImagePointer
  PadInputImageRegion(const RegionType & inputRegion);
  RegionType
  GetPaddedImageRegion(const RegionType & inputRegion);

  void
  PrintSelf(std::ostream & os, itk::Indent indent) const override;

  bool
  IsPrime(int n) const;

  int
  GreatestPrimeFactor(int n) const;

  virtual void
  UpdateFFTProjectionsConvolutionKernel(const SizeType size) = 0;

  virtual void
                                      UpdateTruncationMirrorWeights();
  typename std::vector<TFFTPrecision> m_TruncationMirrorWeights;

  int m_KernelDimension{ 1 };

  FFTOutputImagePointer m_KernelFFT;

private:
  double m_TruncationCorrection{ 0. };
  int
  GetTruncationCorrectionExtent();

  ZeroPadFactorsType m_ZeroPadFactors;

  int m_GreatestPrimeFactor{ 2 };
  int m_BackupNumberOfThreads{ 1 };
}; // end of class

} // end namespace rtk

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

#endif