itkSymmetricEigenAnalysisImageFilter.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 __itkSymmetricEigenAnalysisImageFilter_h
#define __itkSymmetricEigenAnalysisImageFilter_h

#include "itkUnaryFunctorImageFilter.h"
#include "itkSymmetricEigenAnalysis.h"

namespace itk
{
// This functor class invokes the computation of Eigen Analysis for
// every pixel. The input pixel type must provide the API for the [][]
// operator, while the output pixel type must provide the API for the
// [] operator. Input pixel matrices should be symmetric.
//
// The default operation is to order eigen values in ascending order.
// You may also use OrderEigenValuesBy( ) to order eigen values by
// magnitude as is common with use of tensors in vessel extraction.
namespace Functor
{
template< typename TInput, typename TOutput >
class SymmetricEigenAnalysisFunction
{
public:
  typedef typename TInput::RealValueType RealValueType;
  SymmetricEigenAnalysisFunction() {}
  ~SymmetricEigenAnalysisFunction() {}
  typedef SymmetricEigenAnalysis< TInput, TOutput > CalculatorType;
  bool operator!=(const SymmetricEigenAnalysisFunction &) const
  {
    return false;
  }

  bool operator==(const SymmetricEigenAnalysisFunction & other) const
  {
    return !( *this != other );
  }

  inline TOutput operator()(const TInput & x) const
  {
    TOutput eigenValues;

    m_Calculator.ComputeEigenValues(x, eigenValues);
    return eigenValues;
  }

  void SetDimension(unsigned int n)
  {
    m_Calculator.SetDimension(n);
  }

  typedef enum {
    OrderByValue = 1,
    OrderByMagnitude,
    DoNotOrder
    } EigenValueOrderType;

  void OrderEigenValuesBy(EigenValueOrderType order)
  {
    if ( order == OrderByMagnitude )
      {
      m_Calculator.SetOrderEigenMagnitudes(true);
      }
    else if ( order == DoNotOrder )
      {
      m_Calculator.SetOrderEigenValues(false);
      }
  }

private:
  CalculatorType m_Calculator;
};
}  // end namespace functor

template< typename  TInputImage, typename  TOutputImage = TInputImage >
class ITK_EXPORT SymmetricEigenAnalysisImageFilter:
  public
  UnaryFunctorImageFilter< TInputImage, TOutputImage,
                           Functor::SymmetricEigenAnalysisFunction<
                             typename TInputImage::PixelType,
                             typename TOutputImage::PixelType > >
{
public:
  typedef SymmetricEigenAnalysisImageFilter Self;
  typedef UnaryFunctorImageFilter<
    TInputImage, TOutputImage,
    Functor::SymmetricEigenAnalysisFunction<
      typename TInputImage::PixelType,
      typename TOutputImage::PixelType > >   Superclass;

  typedef SmartPointer< Self >       Pointer;
  typedef SmartPointer< const Self > ConstPointer;

  typedef typename Superclass::OutputImageType OutputImageType;
  typedef typename TOutputImage::PixelType     OutputPixelType;
  typedef typename TInputImage::PixelType      InputPixelType;
  typedef typename InputPixelType::ValueType   InputValueType;
  typedef typename Superclass::FunctorType     FunctorType;

  typedef typename FunctorType::EigenValueOrderType EigenValueOrderType;

  void OrderEigenValuesBy(EigenValueOrderType order)
  {
    this->GetFunctor().OrderEigenValuesBy(order);
  }

  itkTypeMacro(SymmetricEigenAnalysisImageFilter, UnaryFunctorImageFilter);

  itkNewMacro(Self);

  void PrintSelf(std::ostream & os, Indent indent) const
  { this->Superclass::PrintSelf(os, indent); }

  void SetDimension(unsigned int p)
  {
    this->GetFunctor().SetDimension(p);
  }

#ifdef ITK_USE_CONCEPT_CHECKING

  itkConceptMacro( InputHasNumericTraitsCheck,
                   ( Concept::HasNumericTraits< InputValueType > ) );

#endif
protected:
  SymmetricEigenAnalysisImageFilter() {}
  virtual ~SymmetricEigenAnalysisImageFilter() {}
private:
  SymmetricEigenAnalysisImageFilter(const Self &); //purposely not implemented
  void operator=(const Self &);                    //purposely not implemented
};
} // end namespace itk

#endif