itkImageMomentsCalculator.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 itkImageMomentsCalculator_h
#define itkImageMomentsCalculator_h
 
#include "itkAffineTransform.h"
#include "itkImage.h"
#include "itkSpatialObject.h"
 
#include "vnl/vnl_vector_fixed.h"
#include "vnl/vnl_matrix_fixed.h"
#include "vnl/vnl_diag_matrix.h"
 
namespace itk
{
template <typename TImage>
class ITK_TEMPLATE_EXPORT ImageMomentsCalculator : public Object
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(ImageMomentsCalculator);

  using Self = ImageMomentsCalculator<TImage>;
  using Superclass = Object;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(ImageMomentsCalculator);

  static constexpr unsigned int ImageDimension = TImage::ImageDimension;

  using ScalarType = double;

  using VectorType = Vector<ScalarType, Self::ImageDimension>;

  using SpatialObjectType = SpatialObject<Self::ImageDimension>;

  using SpatialObjectPointer = typename SpatialObjectType::Pointer;
  using SpatialObjectConstPointer = typename SpatialObjectType::ConstPointer;

  using MatrixType = Matrix<ScalarType, Self::ImageDimension, Self::ImageDimension>;

  using ImageType = TImage;

  using ImagePointer = typename ImageType::Pointer;
  using ImageConstPointer = typename ImageType::ConstPointer;

  using AffineTransformType = AffineTransform<double, Self::ImageDimension>;
  using AffineTransformPointer = typename AffineTransformType::Pointer;

  virtual void
  SetImage(const ImageType * image)
  {
    if (m_Image != image)
    {
      m_Image = image;
      this->Modified();
      m_Valid = false;
    }
  }


  virtual void
  SetSpatialObjectMask(const SpatialObject<Self::ImageDimension> * so)
  {
    if (m_SpatialObjectMask != so)
    {
      m_SpatialObjectMask = so;
      this->Modified();
      m_Valid = false;
    }
  }


  void
  Compute();

  ScalarType
  GetTotalMass() const;

  VectorType
  GetFirstMoments() const;

  MatrixType
  GetSecondMoments() const;

  VectorType
  GetCenterOfGravity() const;

  MatrixType
  GetCentralMoments() const;

  VectorType
  GetPrincipalMoments() const;

  MatrixType
  GetPrincipalAxes() const;

  AffineTransformPointer
  GetPrincipalAxesToPhysicalAxesTransform() const;

  AffineTransformPointer
  GetPhysicalAxesToPrincipalAxesTransform() const;
 
protected:
  ImageMomentsCalculator();
  ~ImageMomentsCalculator() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;
 
private:
  bool       m_Valid{}; // Have moments been computed yet?
  ScalarType m_M0{};    // Zeroth moment
  VectorType m_M1{};    // First moments about origin
  MatrixType m_M2{};    // Second moments about origin
  VectorType m_Cg{};    // Center of gravity (physical units)
  MatrixType m_Cm{};    // Second central moments (physical)
  VectorType m_Pm{};    // Principal moments (physical)
  MatrixType m_Pa{};    // Principal axes (physical)
 
  ImageConstPointer         m_Image{};
  SpatialObjectConstPointer m_SpatialObjectMask{};
}; // class ImageMomentsCalculator
} // end namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkImageMomentsCalculator.hxx"
#endif
 
#endif /* itkImageMomentsCalculator_h */