otbWindowedSincInterpolateImageLanczosFunction.h

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/*
 * Copyright (C) 2005-2022 Centre National d'Etudes Spatiales (CNES)
 *
 * This file is part of Orfeo Toolbox
 *
 *     https://www.orfeo-toolbox.org/
 *
 * 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
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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 otbWindowedSincInterpolateImageLanczosFunction_h
#define otbWindowedSincInterpolateImageLanczosFunction_h
 
#include "otbWindowedSincInterpolateImageFunctionBase.h"
#include "vnl/vnl_math.h"
 
namespace otb
{
 
namespace Function
{
template <class TInput = double, class TOutput = double>
class LanczosWindowFunction
{
public:
  LanczosWindowFunction() : m_Radius(1), m_Factor(CONST_PI)
  {
  } // default factor is 1 at construction
  void SetRadius(unsigned int radius)
  {
    m_Radius = radius;
    m_Factor = CONST_PI / static_cast<double>(radius);
  }
  unsigned int GetRadius() const
  {
    return m_Radius;
  }
  double GetFactor()
  {
    return m_Factor;
  }
 
  inline TOutput operator()(const TInput& A) const
  {
    double x  = static_cast<double>(A);
    double px = CONST_PI * x;
    double temp;
    if (x == 0.0)
    {
      temp = 1.0;
    }
    else
    {
      double z = m_Factor * x;
      temp     = std::sin(z) / z;
    }
    return (x == 0.0) ? static_cast<TOutput>(temp) : static_cast<TOutput>(temp * std::sin(px) / px);
  }
 
private:
  unsigned int m_Radius;
  // Equal to \f$ \frac{\pi}{m} \f$
  double m_Factor;
};
} // namespace Function
 
template <class TInputImage, class TBoundaryCondition = itk::ConstantBoundaryCondition<TInputImage>, class TCoordRep = double,
          class TInputInterpolator = double, class TOutputInterpolator = double>
class ITK_EXPORT WindowedSincInterpolateImageLanczosFunction
    : public WindowedSincInterpolateImageFunctionBase<TInputImage, typename Function::LanczosWindowFunction<TInputInterpolator, TOutputInterpolator>,
                                                      TBoundaryCondition, TCoordRep>
{
public:
 
  typedef WindowedSincInterpolateImageLanczosFunction Self;
  typedef WindowedSincInterpolateImageFunctionBase<TInputImage, typename Function::LanczosWindowFunction<TInputInterpolator, TOutputInterpolator>,
                                                   TBoundaryCondition, TCoordRep>
                                        Superclass;
  typedef itk::SmartPointer<Self>       Pointer;
  typedef itk::SmartPointer<const Self> ConstPointer;
 
  itkTypeMacro(WindowedSincInterpolateImageLanczosFunction, WindowedSincInterpolateImageFunctionBase);
 
  itkNewMacro(Self);
 
  typedef typename Superclass::InputImageType InputImageType;
  typedef typename Superclass::OutputType     OutputType;
 
  itkStaticConstMacro(ImageDimension, unsigned int, Superclass::ImageDimension);
 
  typedef typename Superclass::IndexType           IndexType;
  typedef typename Superclass::SizeType            SizeType;
  typedef typename Superclass::RealType            RealType;
  typedef typename Superclass::IteratorType        IteratorType;
  typedef typename Superclass::ContinuousIndexType ContinuousIndexType;
 
protected:
  WindowedSincInterpolateImageLanczosFunction(){};
  ~WindowedSincInterpolateImageLanczosFunction() override
  {
  }
  void PrintSelf(std::ostream& os, itk::Indent indent) const override
  {
    Superclass::PrintSelf(os, indent);
  }
 
private:
  WindowedSincInterpolateImageLanczosFunction(const Self&) = delete;
  void operator=(const Self&) = delete;
};
 
} // end namespace otb
 
#endif