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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkContourDirectedMeanDistanceImageFilter.h,v $
  Language:  C++
  Date:      $Date: 2006/03/27 17:01:04 $
  Version:   $Revision: 1.4 $

  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 __itkContourDirectedMeanDistanceImageFilter_h
#define __itkContourDirectedMeanDistanceImageFilter_h

#include "itkImageToImageFilter.h"
#include "itkNumericTraits.h"
#include "itkArray.h"
#include "itkImage.h"

namespace itk {

/** \class ContourDirectedMeanDistanceImageFilter 
 * \brief Computes the directed Mean distance between the boundaries of 
 * non-zero pixel regions of two images.
 *
 * ContourDirectedMeanDistanceImageFilter computes the distance between the set
 * non-zero pixels of two images using the following formula:
 * \f[ h(A,B) = \mean_{a \in A} \min_{b \in B} \| a - b\| \f]
 * where \f$A\f$ and \f$B\f$ are respectively the set of non-zero pixels
 * in the first and second input images. It identifies the point \f$ a \in A \f$
 * that is farthest from any point of \f$B\f$ and measures the distance from \f$a\f$
 * to the nearest neighbor in \f$B\f$. Note that this function is not
 * is not symmetric and hence is not a true distance.
 *
 * In particular, this filter uses the SignedDanielssonDistanceMapImageFilter inside
 * to compute distance map from all non-zero pixels in the second image. It
 * then computes the mean distance (in pixels) within the boundary pixels of
 * non-zero regions in the first image.
 *
 * Use MeanDistanceImageFilter to compute the full Mean distance.
 *
 * This filter requires the largest possible region of the first image and the
 * same corresponding region in the second image.  It behaves as filter with
 * two input and one output. Thus it can be inserted in a pipeline with other
 * filters. The filter passes the first input through unmodified.
 *
 * This filter is templated over the two input image type. It assume
 * both image have the same number of dimensions.
 *
 * \sa SignedDanielssonDistanceMapImageFilter
 * \sa MeanDistanceImageFilter
 *
 * \ingroup MultiThreaded
 * 
 * \author Teo Popa, ISIS Center, Georgetown University
 *                   
 */
template<class TInputImage1, class TInputImage2>
class ITK_EXPORT ContourDirectedMeanDistanceImageFilter : 
    public ImageToImageFilter<TInputImage1, TInputImage1>
{
public:
  /** Standard Self typedef */
  typedef ContourDirectedMeanDistanceImageFilter Self;
  typedef ImageToImageFilter<TInputImage1,TInputImage1>  Superclass;
  typedef SmartPointer<Self>        Pointer;
  typedef SmartPointer<const Self>  ConstPointer;
  
  /** Method for creation through the object factory. */
  itkNewMacro(Self);  

  /** Runtime information support. */
  itkTypeMacro(ContourDirectedMeanDistanceImageFilter, ImageToImageFilter);
  
  /** Image related typedefs. */
  typedef TInputImage1 InputImage1Type;
  typedef TInputImage2 InputImage2Type;
  typedef typename TInputImage1::Pointer InputImage1Pointer;
  typedef typename TInputImage2::Pointer InputImage2Pointer;
  typedef typename TInputImage1::ConstPointer InputImage1ConstPointer;
  typedef typename TInputImage2::ConstPointer InputImage2ConstPointer;

  typedef typename TInputImage1::RegionType RegionType ;
  typedef typename TInputImage1::SizeType SizeType ;
  typedef typename TInputImage1::IndexType IndexType ;

  typedef typename TInputImage1::PixelType InputImage1PixelType;
  typedef typename TInputImage2::PixelType InputImage2PixelType;
  
  /** Image related typedefs. */
  itkStaticConstMacro(ImageDimension, unsigned int,
                      TInputImage1::ImageDimension);

  /** Type to use form computations. */
  typedef typename NumericTraits<InputImage1PixelType>::RealType RealType;

  /** Set the first input. */
  void SetInput1( const InputImage1Type * image )
  { this->SetInput( image ); }

  /** Set the second input. */
  void SetInput2( const InputImage2Type * image );

  /** Get the first input. */
  const InputImage1Type * GetInput1(void)
  { return this->GetInput(); }
  
  /** Get the second input. */
  const InputImage2Type * GetInput2(void);
  
  /** Return the computed directed Mean distance. */
  itkGetMacro(ContourDirectedMeanDistance,RealType);

#ifdef ITK_USE_CONCEPT_CHECKING
  /** Begin concept checking */
  itkConceptMacro(InputHasNumericTraitsCheck,
    (Concept::HasNumericTraits<InputImage1PixelType>));
  /** End concept checking */
#endif

protected:
  ContourDirectedMeanDistanceImageFilter();
  ~ContourDirectedMeanDistanceImageFilter(){};
  void PrintSelf(std::ostream& os, Indent indent) const;

  /** Pass the input through unmodified. Do this by Grafting in the AllocateOutputs method. */
  void AllocateOutputs();      

  /** Initialize some accumulators before the threads run. */
  void BeforeThreadedGenerateData ();
  
  /** Do final mean and variance computation from data accumulated in threads. */
  void AfterThreadedGenerateData ();
  
  /** Multi-thread version GenerateData. */
  void  ThreadedGenerateData (const RegionType& 
                              outputRegionForThread,
                              int threadId) ;

  // Override since the filter needs all the data for the algorithm
  void GenerateInputRequestedRegion();

  // Override since the filter produces all of its output
  void EnlargeOutputRequestedRegion(DataObject *data);

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

  typedef Image<RealType,itkGetStaticConstMacro(ImageDimension)> DistanceMapType;
  
  typename DistanceMapType::Pointer   m_DistanceMap;
  Array<RealType>                     m_MeanDistance;
  Array<int>                          m_Count;
  RealType                            m_ContourDirectedMeanDistance;

} ; // end of class

} // end namespace itk
  
#ifndef ITK_MANUAL_INSTANTIATION
#include "itkContourDirectedMeanDistanceImageFilter.txx"
#endif

#endif
