itkPSMImageDomainWithHessians.h

/*=========================================================================
 *
 *  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 __itkPSMImageDomainWithHessians_h
#define __itkPSMImageDomainWithHessians_h

#include "itkImage.h"
#include "itkPSMImageDomainWithGradients.h"
#include "itkLinearInterpolateImageFunction.h"
#include "itkGradientImageFilter.h"
#include "itkFixedArray.h"
#include "itkImageDuplicator.h"
#include "itkDiscreteGaussianImageFilter.h"
#include "itkDerivativeImageFilter.h"
#include "vnl/vnl_matrix_fixed.h"

namespace itk
{
template <class T, unsigned int VDimension>
class ITK_EXPORT PSMImageDomainWithHessians
  : public PSMImageDomainWithGradients<T, VDimension>
{
public:
  typedef PSMImageDomainWithHessians Self;
  typedef PSMImageDomainWithGradients<T, VDimension> Superclass;
  typedef SmartPointer<Self>  Pointer;
  typedef SmartPointer<const Self> ConstPointer;
  typedef WeakPointer<const Self>  ConstWeakPointer;

  typedef typename Superclass::PointType PointType;
  
  typedef typename Superclass::ImageType ImageType;
  typedef typename Superclass::ScalarInterpolatorType ScalarInterpolatorType;
  typedef vnl_matrix_fixed<T, VDimension, VDimension> VnlMatrixType;
  
  itkNewMacro(Self);

  itkTypeMacro(PSMImageDomainWithHessians, PSMImageDomainWithGradients);

  itkStaticConstMacro(Dimension, unsigned int, VDimension);

  void SetImage(ImageType *I)
  {
    Superclass::SetImage(I);
    
    typename DiscreteGaussianImageFilter<ImageType, ImageType>::Pointer
      gaussian = DiscreteGaussianImageFilter<ImageType, ImageType>::New();
    gaussian->SetVariance(m_Sigma * m_Sigma);
    gaussian->SetInput(this->GetImage());
    gaussian->SetUseImageSpacingOn();
    gaussian->Update();
    
    // Compute the second derivatives and set up the interpolators
    for (unsigned int i = 0; i < VDimension; i++)
      {
      typename DerivativeImageFilter<ImageType, ImageType>::Pointer
        deriv = DerivativeImageFilter<ImageType, ImageType>::New();
      deriv->SetInput(gaussian->GetOutput());
      deriv->SetDirection(i);
      deriv->SetOrder(2);
      deriv->SetUseImageSpacingOn();
      deriv->Update();

      m_PartialDerivatives[i] = deriv->GetOutput();

      m_Interpolators[i] = ScalarInterpolatorType::New();
      m_Interpolators[i]->SetInputImage(m_PartialDerivatives[i]);
      }

    // Compute the cross derivatives and set up the interpolators
    unsigned int k = VDimension;
    for (unsigned int i = 0; i < VDimension; i++)
      {
      for (unsigned int j = i+1; j < VDimension; j++, k++)
        {
        typename DerivativeImageFilter<ImageType, ImageType>::Pointer
          deriv1 = DerivativeImageFilter<ImageType, ImageType>::New();
        deriv1->SetInput(gaussian->GetOutput());
        deriv1->SetDirection(i);
        deriv1->SetUseImageSpacingOn();
        deriv1->SetOrder(1);
        deriv1->Update();

        typename DerivativeImageFilter<ImageType, ImageType>::Pointer
          deriv2 = DerivativeImageFilter<ImageType, ImageType>::New();
        deriv2->SetInput(deriv1->GetOutput());
        deriv2->SetDirection(j);
        deriv2->SetUseImageSpacingOn();
        deriv2->SetOrder(1);
        
        deriv2->Update();
        
        m_PartialDerivatives[k] = deriv2->GetOutput();
        m_Interpolators[k] = ScalarInterpolatorType::New();
        m_Interpolators[k]->SetInputImage(m_PartialDerivatives[k]);
        }
      }
  } // end setimage
  
  inline VnlMatrixType SampleHessianVnl(const PointType &p) const
  {
    VnlMatrixType ans;
    for (unsigned int i = 0; i < VDimension; i++)
      {      ans[i][i] = m_Interpolators[i]->Evaluate(p);      }
    
    // Cross derivatives
    unsigned int k = VDimension;
    for (unsigned int i =0; i < VDimension; i++)
      {
      for (unsigned int j = i+1; j < VDimension; j++, k++)
        {
        ans[i][j] = ans[j][i] = m_Interpolators[k]->Evaluate(p);
        }
      }
    return ans;
  }
  
  itkSetMacro(Sigma, double);
  itkGetMacro(Sigma, double);

  typename ScalarInterpolatorType::Pointer *GetInterpolators()
  { return m_Interpolators; }
  typename ImageType::Pointer *GetPartialDerivatives()
  { return m_PartialDerivatives; }
  
protected:
  PSMImageDomainWithHessians() : m_Sigma(0.0)
  {  }

  void PrintSelf(std::ostream& os, Indent indent) const
  {
    Superclass::PrintSelf(os, indent);
  }
  virtual ~PSMImageDomainWithHessians() {};

  void DeletePartialDerivativeImages()
  {
    for (unsigned int i = 0; i < VDimension + ((VDimension * VDimension) - VDimension) / 2; i++)
      {
      m_PartialDerivatives[i]=0;
      m_Interpolators[i]=0;
      }
  }
  
private:
  double m_Sigma;
  
  PSMImageDomainWithHessians(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented

  // Partials are stored:
  //     0: dxx  3: dxy  4: dxz
  //                 1: dyy  5: dyz
  //                            2: dzz
  //
  typename ImageType::Pointer  m_PartialDerivatives[ VDimension + ((VDimension * VDimension) - VDimension) / 2];

  typename ScalarInterpolatorType::Pointer m_Interpolators[VDimension + ((VDimension * VDimension) - VDimension) / 2];
};

} // end namespace itk

#endif