itkFrequencyImageRegionConstIteratorWithIndex.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 itkFrequencyImageRegionConstIteratorWithIndex_h
#define itkFrequencyImageRegionConstIteratorWithIndex_h
 
#include "itkImageRegionConstIteratorWithIndex.h"
 
namespace itk
{
template <typename TImage>
class ITK_TEMPLATE_EXPORT FrequencyImageRegionConstIteratorWithIndex : public ImageRegionConstIteratorWithIndex<TImage>
{
public:
  using Self = FrequencyImageRegionConstIteratorWithIndex;
  using Superclass = ImageRegionConstIteratorWithIndex<TImage>;

  using typename Superclass::IndexType;
  using typename Superclass::SizeType;
  using typename Superclass::OffsetType;
  using typename Superclass::RegionType;
  using typename Superclass::ImageType;
  using typename Superclass::PixelContainer;
  using typename Superclass::PixelContainerPointer;
  using typename Superclass::InternalPixelType;
  using typename Superclass::PixelType;
  using typename Superclass::AccessorType;
 
  using FrequencyType = typename ImageType::SpacingType;
  using FrequencyValueType = typename ImageType::SpacingValueType;
  FrequencyImageRegionConstIteratorWithIndex()
    : ImageRegionConstIteratorWithIndex<TImage>()
  {
    this->Init();
  }

  FrequencyImageRegionConstIteratorWithIndex(const TImage * ptr, const RegionType & region)
    : ImageRegionConstIteratorWithIndex<TImage>(ptr, region)
  {
    this->Init();
  }

  explicit FrequencyImageRegionConstIteratorWithIndex(const Superclass & it)
    : ImageRegionConstIteratorWithIndex<TImage>(it)
  {
    this->Init();
  }
 
  /*
   * The image is in the frequency domain already, return the index.
   */
  IndexType
  GetFrequencyBin() const
  {
    return this->GetIndex();
  }
 
  /* Similar to TransformIndexToPhysicalPoint on GetIndex(),
   * but the result is cast to FrequencyType. And direction is not taken into account.
   */
  FrequencyType
  GetFrequency() const
  {
    FrequencyType freq;
    IndexType     freqInd = this->GetFrequencyBin();
    // FrequencyType freq;
    for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
    {
      freq[dim] = this->m_FrequencyOrigin[dim] + this->m_FrequencySpacing[dim] * freqInd[dim];
    }
    return freq;
  }
 
  FrequencyValueType
  GetFrequencyModuloSquare() const
  {
    FrequencyValueType w2(0);
    FrequencyType      w(this->GetFrequency());
 
    for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
    {
      w2 += w[dim] * w[dim];
    }
    return w2;
  }

  itkGetConstReferenceMacro(FrequencyOrigin, FrequencyType);

  itkGetConstReferenceMacro(FrequencySpacing, FrequencyType);
 
private:
  void
  Init()
  {
    for (unsigned int dim = 0; dim < ImageType::ImageDimension; ++dim)
    {
      this->m_FrequencyOrigin[dim] = this->m_Image->GetOrigin()[dim];
      this->m_FrequencySpacing[dim] = this->m_Image->GetSpacing()[dim];
    }
  }
 
  FrequencyType m_FrequencyOrigin;
  FrequencyType m_FrequencySpacing;
};
} // end namespace itk
#endif