itkWindowedSincInterpolateImageFunction.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 itkWindowedSincInterpolateImageFunction_h
#define itkWindowedSincInterpolateImageFunction_h
 
#include "itkConstNeighborhoodIterator.h"
#include "itkZeroFluxNeumannBoundaryCondition.h"
#include "itkInterpolateImageFunction.h"
#include "itkMath.h"
 
namespace itk
{
// clang-format off
namespace Function
{
template <unsigned int VRadius, typename TInput = double, typename TOutput = double>
class ITK_TEMPLATE_EXPORT CosineWindowFunction
{
public:
  inline TOutput
  operator()(const TInput & A) const
  {

    static constexpr double factor = Math::pi / (2 * VRadius);
    return static_cast<TOutput>(std::cos(A * factor));
  }
};

template <unsigned int VRadius, typename TInput = double, typename TOutput = double>
class ITK_TEMPLATE_EXPORT HammingWindowFunction
{
public:
  inline TOutput
  operator()(const TInput & A) const
  {

    static constexpr double factor = Math::pi / VRadius;
    return static_cast<TOutput>(0.54 + 0.46 * std::cos(A * factor));
  }
};

template <unsigned int VRadius, typename TInput = double, typename TOutput = double>
class ITK_TEMPLATE_EXPORT WelchWindowFunction
{
public:
  inline TOutput
  operator()(const TInput & A) const
  {
 
    static constexpr double factor = 1.0 / (VRadius * VRadius);
    return static_cast<TOutput>(1.0 - A * factor * A);
  }
};

template <unsigned int VRadius, typename TInput = double, typename TOutput = double>
class ITK_TEMPLATE_EXPORT LanczosWindowFunction
{
public:
  inline TOutput
  operator()(const TInput & A) const
  {
    if (A == 0.0)
    {
      return static_cast<TOutput>(1.0);
    } // namespace Function

    static constexpr double factor = Math::pi / VRadius;
    const double z = factor * A;
    return static_cast<TOutput>(std::sin(z) / z);
  } // namespace itk
};

template <unsigned int VRadius, typename TInput = double, typename TOutput = double>
class ITK_TEMPLATE_EXPORT BlackmanWindowFunction
{
public:
  inline TOutput
  operator()(const TInput & A) const
  {

    static constexpr double factor1 = Math::pi / VRadius;

    static constexpr double factor2 = 2.0 * Math::pi / VRadius;
    return static_cast<TOutput>(0.42 + 0.5 * std::cos(A * factor1) + 0.08 * std::cos(A * factor2));
  }
};
} // namespace Function
// clang-format on

template <typename TInputImage,
          unsigned int VRadius,
          typename TWindowFunction = Function::HammingWindowFunction<VRadius>,
          class TBoundaryCondition = ZeroFluxNeumannBoundaryCondition<TInputImage, TInputImage>,
          class TCoordinate = double>
class ITK_TEMPLATE_EXPORT WindowedSincInterpolateImageFunction
  : public InterpolateImageFunction<TInputImage, TCoordinate>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(WindowedSincInterpolateImageFunction);

  using Self = WindowedSincInterpolateImageFunction;
  using Superclass = InterpolateImageFunction<TInputImage, TCoordinate>;
 
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkOverrideGetNameOfClassMacro(WindowedSincInterpolateImageFunction);

  itkNewMacro(Self);

  using typename Superclass::OutputType;

  using typename Superclass::InputImageType;

  using typename Superclass::RealType;

  static constexpr unsigned int ImageDimension = Superclass::ImageDimension;

  using typename Superclass::IndexType;
  using typename Superclass::IndexValueType;

  using typename Superclass::SizeType;

  using ImageType = TInputImage;

  using typename Superclass::ContinuousIndexType;
 
  void
  SetInputImage(const ImageType * image) override;

  OutputType
  EvaluateAtContinuousIndex(const ContinuousIndexType & index) const override;
 
  SizeType
  GetRadius() const override
  {
    constexpr auto radius = SizeType::Filled(VRadius);
    return radius;
  }
 
protected:
  WindowedSincInterpolateImageFunction() = default;
  ~WindowedSincInterpolateImageFunction() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;
 
private:
  // Internal type alias
  using IteratorType = ConstNeighborhoodIterator<ImageType, TBoundaryCondition>;
 
  // Constant to store twice the radius
  static constexpr unsigned int m_WindowSize{ 2 * VRadius };

  TWindowFunction m_WindowFunction{};

  static constexpr unsigned int m_OffsetTableSize = Math::UnsignedPower(m_WindowSize, ImageDimension);

  unsigned int m_OffsetTable[m_OffsetTableSize]{};

  unsigned int m_WeightOffsetTable[m_OffsetTableSize][ImageDimension]{};

  static double
  Sinc(const double x)
  {
    const double px = Math::pi * x;
    return (x == 0.0) ? 1.0 : std::sin(px) / px;
  }
};
} // namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkWindowedSincInterpolateImageFunction.hxx"
#endif
 
#endif // _itkWindowedSincInterpolateImageFunction_h