itkImageMomentsCalculator.h

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/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  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.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_ASSIGN(ImageMomentsCalculator);

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

  itkNewMacro(Self);

  itkTypeMacro(ImageMomentsCalculator, Object);

  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 */