otbSinclairToReciprocalCoherencyMatrixImageFilter.h

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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 otbSinclairToReciprocalCoherencyMatrixImageFilter_h
#define otbSinclairToReciprocalCoherencyMatrixImageFilter_h
 
#include "itkMacro.h"
#include <complex>
#include "otbMath.h"
#include "vnl/vnl_matrix.h"
 
#include "otbFunctorImageFilter.h"
#include "otbPolarimetryTags.h"
 
namespace otb
{
namespace Functor
{
template <class TInput1, class TInput2, class TInput3, class TOutput>
class SinclairToReciprocalCoherencyMatrixFunctor
{
public:
  typedef typename std::complex<double> ComplexType;
  typedef vnl_matrix<ComplexType>       VNLMatrixType;
  typedef typename TOutput::ValueType   OutputValueType;
 
  inline void operator()(TOutput& result, const TInput1& Shh, const TInput2& Shv, const TInput3& Svv) const
  {
    const ComplexType S_hh = static_cast<ComplexType>(Shh);
    const ComplexType S_hv = static_cast<ComplexType>(Shv);
    const ComplexType S_vv = static_cast<ComplexType>(Svv);
 
    VNLMatrixType f3p(3, 1, 0.);
    f3p[0][0] = (S_hh + S_vv) / ComplexType(std::sqrt(2.0), 0.0);
    f3p[1][0] = (S_hh - S_vv) / ComplexType(std::sqrt(2.0), 0.0);
    f3p[2][0] = ComplexType(std::sqrt(2.0), 0.0) * S_hv;
 
    VNLMatrixType res = f3p * f3p.conjugate_transpose();
 
    result[0] = static_cast<OutputValueType>(res[0][0]);
    result[1] = static_cast<OutputValueType>(res[0][1]);
    result[2] = static_cast<OutputValueType>(res[0][2]);
    result[3] = static_cast<OutputValueType>(res[1][1]);
    result[4] = static_cast<OutputValueType>(res[1][2]);
    result[5] = static_cast<OutputValueType>(res[2][2]);
  }
 
  constexpr size_t OutputSize(...) const
  {
    // Size of the  matrix
    return 6;
  }
};
 
} // namespace Functor
 
template <typename TInputImage, typename TOutputImage>
using SinclairToReciprocalCoherencyMatrixImageFilter =
    FunctorImageFilter<Functor::SinclairToReciprocalCoherencyMatrixFunctor<typename TInputImage::PixelType, typename TInputImage::PixelType,
                                                                           typename TInputImage::PixelType, typename TOutputImage::PixelType>,
                       std::tuple<polarimetry_tags::hh, polarimetry_tags::hv_or_vh, polarimetry_tags::vv>>;
 
} // namespace otb
 
#endif