itkWeightedAddImageFilter.h

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/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkWeightedAddImageFilter.h,v $
  Language:  C++
  Date:      $Date: 2009-04-01 14:36:37 $
  Version:   $Revision: 1.7 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef __itkWeightedAddImageFilter_h
#define __itkWeightedAddImageFilter_h

#include "itkBinaryFunctorImageFilter.h"
#include "itkNumericTraits.h"


namespace itk
{
  
namespace Functor {  
  
template< class TInput1, class TInput2, class TOutput >
class WeightedAdd2
{
public:
  typedef typename NumericTraits< TInput1 >::AccumulateType AccumulatorType;
  typedef typename NumericTraits< TInput1 >::RealType       RealType;
  WeightedAdd2() {};
  ~WeightedAdd2() {};
  bool operator!=( const WeightedAdd2 & other ) const
    {
    if( m_Alpha != other.m_Alpha)
      {
      return true;
      }
    return false;
    }
  bool operator==( const WeightedAdd2 & other ) const
    {
    return !(*this != other);
    }

  inline TOutput operator()( const TInput1 & A, const TInput2 & B) const
    {
    const RealType sum1 = A * m_Alpha;
    const RealType sum2 = B * m_Beta;
    return static_cast<TOutput>( sum1 + sum2 );
    }
  void SetAlpha( RealType alpha )
    { 
    m_Alpha = alpha; 
    m_Beta  = NumericTraits< RealType >::One - m_Alpha;
    }
  RealType GetAlpha() const
    {
    return m_Alpha;
    }
private:
  RealType  m_Alpha;
  RealType  m_Beta;    // auxiliary var to avoid a subtraction at every pixel
}; 

}
template <class TInputImage1, class TInputImage2, class TOutputImage>
class ITK_EXPORT WeightedAddImageFilter :
    public
BinaryFunctorImageFilter<TInputImage1,TInputImage2,TOutputImage, 
                         Functor::WeightedAdd2< 
  typename TInputImage1::PixelType, 
  typename TInputImage2::PixelType,
  typename TOutputImage::PixelType>   >


{
public:
  typedef WeightedAddImageFilter    Self;
  typedef BinaryFunctorImageFilter<TInputImage1,TInputImage2,TOutputImage, 
                                   Functor::WeightedAdd2< 
    typename TInputImage1::PixelType, 
    typename TInputImage2::PixelType,
    typename TOutputImage::PixelType>   
  >                                 Superclass;
  typedef SmartPointer<Self>        Pointer;
  typedef SmartPointer<const Self>  ConstPointer;

  typedef typename Superclass::FunctorType    FunctorType;
  typedef typename FunctorType::RealType      RealType;

  itkNewMacro(Self);
  
  itkTypeMacro(WeightedAddImageFilter, 
               BinaryFunctorImageFilter);

  void SetAlpha( RealType alpha ) 
    {
    this->GetFunctor().SetAlpha( alpha );
    this->Modified();
    }

#ifdef ITK_USE_CONCEPT_CHECKING

  itkConceptMacro(Input1HasNumericTraitsCheck,
    (Concept::HasNumericTraits<typename TInputImage1::PixelType>));
  itkConceptMacro(Input1RealTypeMultiplyCheck,
    (Concept::MultiplyOperator<typename TInputImage1::PixelType,
                               RealType, RealType>));
  itkConceptMacro(Input2RealTypeMultiplyCheck,
    (Concept::MultiplyOperator<typename TInputImage2::PixelType,
                               RealType, RealType>));
#endif

protected:
  WeightedAddImageFilter() {}
  virtual ~WeightedAddImageFilter() {}

private:
  WeightedAddImageFilter(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented

};

} // end namespace itk


#endif