itkFFTConvolutionImageFilter.h

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/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  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 itkFFTConvolutionImageFilter_h
#define itkFFTConvolutionImageFilter_h
 
#include "itkConvolutionImageFilterBase.h"
 
#include "itkProgressAccumulator.h"
#include "itkHalfHermitianToRealInverseFFTImageFilter.h"
#include "itkRealToHalfHermitianForwardFFTImageFilter.h"
#include "itkZeroFluxNeumannBoundaryCondition.h"
 
namespace itk
{
template <typename TInputImage,
          typename TKernelImage = TInputImage,
          typename TOutputImage = TInputImage,
          typename TInternalPrecision = double>
class ITK_TEMPLATE_EXPORT FFTConvolutionImageFilter
  : public ConvolutionImageFilterBase<TInputImage, TKernelImage, TOutputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(FFTConvolutionImageFilter);
 
  using Self = FFTConvolutionImageFilter;
  using Superclass = ConvolutionImageFilterBase<TInputImage, TKernelImage, TOutputImage>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(FFTConvolutionImageFilter);

  static constexpr unsigned int ImageDimension = TInputImage::ImageDimension;
 
  using InputImageType = TInputImage;
  using OutputImageType = TOutputImage;
  using KernelImageType = TKernelImage;
  using InputPixelType = typename InputImageType::PixelType;
  using OutputPixelType = typename OutputImageType::PixelType;
  using KernelPixelType = typename KernelImageType::PixelType;
  using InputIndexType = typename InputImageType::IndexType;
  using OutputIndexType = typename OutputImageType::IndexType;
  using KernelIndexType = typename KernelImageType::IndexType;
  using InputSizeType = typename InputImageType::SizeType;
  using OutputSizeType = typename OutputImageType::SizeType;
  using KernelSizeType = typename KernelImageType::SizeType;
  using SizeValueType = typename InputSizeType::SizeValueType;
  using InputRegionType = typename InputImageType::RegionType;
  using OutputRegionType = typename OutputImageType::RegionType;
  using KernelRegionType = typename KernelImageType::RegionType;

  using InternalImageType = Image<TInternalPrecision, TInputImage::ImageDimension>;
  using InternalRegionType = typename InternalImageType::RegionType;
  using InternalSizeType = typename InternalImageType::SizeType;
  using InternalIndexType = typename InternalImageType::IndexType;
  using InternalImagePointerType = typename InternalImageType::Pointer;
  using InternalComplexType = std::complex<TInternalPrecision>;
  using InternalComplexImageType = Image<InternalComplexType, TInputImage::ImageDimension>;
  using InternalComplexImagePointerType = typename InternalComplexImageType::Pointer;

  using typename Superclass::BoundaryConditionType;
 
  itkSetMacro(SizeGreatestPrimeFactor, SizeValueType);
  itkGetMacro(SizeGreatestPrimeFactor, SizeValueType);
 
protected:
  FFTConvolutionImageFilter();
  ~FFTConvolutionImageFilter() override = default;

  using FFTFilterType = RealToHalfHermitianForwardFFTImageFilter<InternalImageType, InternalComplexImageType>;
  using IFFTFilterType = HalfHermitianToRealInverseFFTImageFilter<InternalComplexImageType, InternalImageType>;

  void
  GenerateInputRequestedRegion() override;

  void
  GenerateData() override;

  void
  PrepareInputs(const InputImageType *            input,
                const KernelImageType *           kernel,
                InternalComplexImagePointerType & preparedInput,
                InternalComplexImagePointerType & preparedKernel,
                ProgressAccumulator *             progress,
                float                             progressWeight);

  void
  PrepareInput(const InputImageType *            input,
               InternalComplexImagePointerType & preparedInput,
               ProgressAccumulator *             progress,
               float                             progressWeight);

  void
  PadInput(const InputImageType *     input,
           InternalImagePointerType & paddedInput,
           ProgressAccumulator *      progress,
           float                      progressWeight);

  void
  TransformPaddedInput(const InternalImageType *         paddedInput,
                       InternalComplexImagePointerType & transformedInput,
                       ProgressAccumulator *             progress,
                       float                             progressWeight);

  void
  PrepareKernel(const KernelImageType *           kernel,
                InternalComplexImagePointerType & preparedKernel,
                ProgressAccumulator *             progress,
                float                             progressWeight);

  void
  ProduceOutput(InternalComplexImageType * paddedOutput, ProgressAccumulator * progress, float progressWeight);

  void
  CropOutput(InternalImageType * paddedOutput, ProgressAccumulator * progress, float progressWeight);

  KernelSizeType
  GetKernelRadius() const;

  InternalSizeType
  GetFFTPadSize() const;

  [[nodiscard]] bool
  GetXDimensionIsOdd() const;
 
  void
  PrintSelf(std::ostream & os, Indent indent) const override;
 
private:
  SizeValueType      m_SizeGreatestPrimeFactor{};
  InternalSizeType   m_FFTPadSize{ { 0 } };
  InternalRegionType m_PaddedInputRegion{};
};
} // namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkFFTConvolutionImageFilter.hxx"
#endif
 
#endif