itkHistogramToProbabilityImageFilter.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 __itkHistogramToProbabilityImageFilter_h
#define __itkHistogramToProbabilityImageFilter_h

#include "itkHistogramToImageFilter.h"

namespace itk
{
namespace Function
{
template< typename TInput, typename TOutput = float >
class HistogramProbabilityFunction
{
public:

  //Probability function = Number of occurrences in each bin /
  //   Total Number of occurrences.
  //
  // Returns pixels of float..
  typedef  TOutput OutputPixelType;

  HistogramProbabilityFunction():
    m_TotalFrequency(1) {}

  ~HistogramProbabilityFunction() {}

  inline OutputPixelType operator()(const TInput & A) const
  {
    return static_cast< OutputPixelType >( static_cast< OutputPixelType >( A )
                                           / static_cast< OutputPixelType >( m_TotalFrequency ) );
  }

  void SetTotalFrequency(SizeValueType n)
  {
    m_TotalFrequency = n;
  }

  SizeValueType GetTotalFrequency() const
  {
    return m_TotalFrequency;
  }

private:
  SizeValueType m_TotalFrequency;
};
}

template< typename THistogram, typename TImage=Image< float, 3> >
class HistogramToProbabilityImageFilter:
  public HistogramToImageFilter< THistogram, TImage,
                                 Function::HistogramProbabilityFunction< SizeValueType, typename TImage::PixelType > >
{
public:

  typedef HistogramToProbabilityImageFilter Self;

  typedef HistogramToImageFilter< THistogram, TImage,
                                 Function::HistogramProbabilityFunction< SizeValueType, typename TImage::PixelType > >
  Superclass;

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

  itkTypeMacro(HistogramToProbabilityImageFilter, HistogramToImageFilter);

  itkNewMacro(Self);

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

private:
  HistogramToProbabilityImageFilter(const Self &); //purposely not implemented
  void operator=(const Self &);                    //purposely not implemented
};
} // end namespace itk

#endif