otbKuanImageFilter.hxx

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/*
 * Copyright (C) 2005-2024 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 otbKuanImageFilter_hxx
#define otbKuanImageFilter_hxx
 
#include "otbKuanImageFilter.h"
 
#include "itkDataObject.h"
#include "itkConstNeighborhoodIterator.h"
#include "itkNeighborhoodInnerProduct.h"
#include "itkImageRegionIterator.h"
#include "itkNeighborhoodAlgorithm.h"
#include "itkOffset.h"
 
namespace otb
{
 
template <class TInputImage, class TOutputImage>
KuanImageFilter<TInputImage, TOutputImage>::KuanImageFilter()
{
  m_Radius.Fill(1);
  SetNbLooks(1.0);
  this->DynamicMultiThreadingOn();
}
 
template <class TInputImage, class TOutputImage>
void KuanImageFilter<TInputImage, TOutputImage>::GenerateInputRequestedRegion()
{
  // call the superclass' implementation of this method
  Superclass::GenerateInputRequestedRegion();
 
  // get pointers to the input and output
  typename Superclass::InputImagePointer  inputPtr  = const_cast<TInputImage*>(this->GetInput());
  typename Superclass::OutputImagePointer outputPtr = this->GetOutput();
 
  if (!inputPtr || !outputPtr)
  {
    return;
  }
 
  // get a copy of the input requested region (should equal the output
  // requested region)
  typename TInputImage::RegionType inputRequestedRegion;
  inputRequestedRegion = inputPtr->GetRequestedRegion();
 
  // pad the input requested region by the operator radius
  inputRequestedRegion.PadByRadius(m_Radius);
 
  // crop the input requested region at the input's largest possible region
  if (inputRequestedRegion.Crop(inputPtr->GetLargestPossibleRegion()))
  {
    inputPtr->SetRequestedRegion(inputRequestedRegion);
    return;
  }
  else
  {
    // Couldn't crop the region (requested region is outside the largest
    // possible region).  Throw an exception.
 
    // store what we tried to request (prior to trying to crop)
    inputPtr->SetRequestedRegion(inputRequestedRegion);
 
    // build an exception
    itk::InvalidRequestedRegionError e(__FILE__, __LINE__);
    std::ostringstream               msg;
    msg << static_cast<const char*>(this->GetNameOfClass()) << "::GenerateInputRequestedRegion()";
    e.SetLocation(msg.str());
    e.SetDescription("Requested region is (at least partially) outside the largest possible region.");
    e.SetDataObject(inputPtr);
    throw e;
  }
}
 
template <class TInputImage, class TOutputImage>
void KuanImageFilter<TInputImage, TOutputImage>::DynamicThreadedGenerateData(const OutputImageRegionType& outputRegionForThread)
{
  unsigned int                                          i;
  itk::ZeroFluxNeumannBoundaryCondition<InputImageType> nbc;
 
  itk::ConstNeighborhoodIterator<InputImageType> bit;
  itk::ImageRegionIterator<OutputImageType>      it;
 
  typename OutputImageType::Pointer     output = this->GetOutput();
  typename InputImageType::ConstPointer input  = this->GetInput();
 
  // Find the data-set boundary "faces"
  typename itk::NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType>::FaceListType           faceList;
  typename itk::NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType>::FaceListType::iterator fit;
 
  itk::NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType> bC;
  faceList = bC(input, outputRegionForThread, m_Radius);
 
  //  InputRealType pixel;
  InputRealType sum;
  InputRealType sum2;
 
  double Ci2, Cu2, w, E_I, I, Var_I, dPixel;
 
  // Compute the ratio using the number of looks
  Cu2 = 1.0 / m_NbLooks;
 
  // Process each of the boundary faces.  These are N-d regions which border
  // the edge of the buffer.
  for (fit = faceList.begin(); fit != faceList.end(); ++fit)
  {
    bit                                 = itk::ConstNeighborhoodIterator<InputImageType>(m_Radius, input, *fit);
    const unsigned int neighborhoodSize = bit.Size();
    it                                  = itk::ImageRegionIterator<OutputImageType>(output, *fit);
    bit.OverrideBoundaryCondition(&nbc);
 
    bit.GoToBegin();
    it.GoToBegin();
 
 
    while (!bit.IsAtEnd())
    {
      sum  = itk::NumericTraits<InputRealType>::Zero;
      sum2 = itk::NumericTraits<InputRealType>::Zero;
 
      // Parcours du voisinage
      for (i = 0; i < neighborhoodSize; ++i)
      {
        dPixel = static_cast<double>(bit.GetPixel(i));
        sum += dPixel;
      }
      E_I = sum / static_cast<double>(neighborhoodSize);
 
      for (i = 0; i < neighborhoodSize; ++i)
      {
        dPixel = static_cast<double>(bit.GetPixel(i));
        sum2 += (dPixel - E_I) * (dPixel - E_I);
      }
      Var_I = sum2 / static_cast<double>(neighborhoodSize - 1);
 
      I = static_cast<double>(bit.GetCenterPixel());
 
      Ci2 = Var_I / (E_I * E_I);
 
      const double epsilon = 0.0000000001;
      if (std::abs(E_I) < epsilon)
      {
        dPixel = itk::NumericTraits<OutputPixelType>::Zero;
      }
      else if (std::abs(Var_I) < epsilon)
      {
        dPixel = E_I;
      }
      else if (Ci2 < Cu2)
      {
        dPixel = E_I;
      }
      else
      {
        w      = (1 - Cu2 / Ci2) / (1 + Cu2);
        dPixel = I * w + E_I * (1 - w);
      }
 
      // set the weighted value
      it.Set(static_cast<OutputPixelType>(dPixel));
 
      ++bit;
      ++it;
 
    }
  }
}
 
template <class TInputImage, class TOutput>
void KuanImageFilter<TInputImage, TOutput>::PrintSelf(std::ostream& os, itk::Indent indent) const
{
  Superclass::PrintSelf(os, indent);
  os << indent << "Radius: " << m_Radius << std::endl;
}
 
} // end namespace otb
 
#endif