opencv_contrib/modules/optflow/include/opencv2/optflow/sparse_matching_gpc.hpp

/*
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                       (3-clause BSD License)

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    this list of conditions and the following disclaimer.

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/*
Implementation of the Global Patch Collider algorithm from the following paper:
http://research.microsoft.com/en-us/um/people/pkohli/papers/wfrik_cvpr2016.pdf

@InProceedings{Wang_2016_CVPR,
 author = {Wang, Shenlong and Ryan Fanello, Sean and Rhemann, Christoph and Izadi, Shahram and Kohli, Pushmeet},
 title = {The Global Patch Collider},
 booktitle = {The IEEE Conference on Computer Vision and Pattern Recognition (CVPR)},
 month = {June},
 year = {2016}
}
*/

#ifndef __OPENCV_OPTFLOW_SPARSE_MATCHING_GPC_HPP__
#define __OPENCV_OPTFLOW_SPARSE_MATCHING_GPC_HPP__

#include "opencv2/core.hpp"

namespace cv
{
namespace optflow
{

struct CV_EXPORTS_W GPCPatchDescriptor
{
  static const unsigned nFeatures = 18; // number of features in a patch descriptor
  Vec< double, nFeatures > feature;

  GPCPatchDescriptor( const Mat *imgCh, int i, int j );
};

typedef std::pair< GPCPatchDescriptor, GPCPatchDescriptor > GPCPatchSample;
typedef std::vector< GPCPatchSample > GPCSamplesVector;

/** @brief Class encapsulating training samples.
 */
class CV_EXPORTS_W GPCTrainingSamples
{
private:
  GPCSamplesVector samples;

public:
  /** @brief This function can be used to extract samples from a pair of images and a ground truth flow.
   * Sizes of all the provided vectors must be equal.
   */
  static Ptr< GPCTrainingSamples > create( const std::vector< String > &imagesFrom, const std::vector< String > &imagesTo,
                                           const std::vector< String > &gt );

  size_t size() const { return samples.size(); }

  operator GPCSamplesVector() const { return samples; }

  operator GPCSamplesVector &() { return samples; }
};

class CV_EXPORTS_W GPCTree : public Algorithm
{
public:
  struct Node
  {
    Vec< double, GPCPatchDescriptor::nFeatures > coef; // hyperplane coefficients
    double rhs;
    unsigned left;
    unsigned right;

    bool operator==( const Node &n ) const { return coef == n.coef && rhs == n.rhs && left == n.left && right == n.right; }
  };

private:
  typedef GPCSamplesVector::iterator SIter;

  std::vector< Node > nodes;

  bool trainNode( size_t nodeId, SIter begin, SIter end, unsigned depth );

public:
  void train( GPCSamplesVector &samples );

  void write( FileStorage &fs ) const;

  void read( const FileNode &fn );

  static Ptr< GPCTree > create() { return makePtr< GPCTree >(); }

  bool operator==( const GPCTree &t ) const { return nodes == t.nodes; }
};

template < int T > class CV_EXPORTS_W GPCForest : public Algorithm
{
private:
  GPCTree tree[T];

public:
  /** @brief Train the forest using one sample set for every tree.
   * Please, consider using the next method instead of this one for better quality.
   */
  void train( GPCSamplesVector &samples )
  {
    for ( int i = 0; i < T; ++i )
      tree[i].train( samples );
  }

  /** @brief Train the forest using individual samples for each tree.
   * It is generally better to use this instead of the first method.
   */
  void train( const std::vector< String > &imagesFrom, const std::vector< String > &imagesTo, const std::vector< String > &gt )
  {
    for ( int i = 0; i < T; ++i )
    {
      Ptr< GPCTrainingSamples > samples = GPCTrainingSamples::create( imagesFrom, imagesTo, gt ); // Create training set for the tree
      tree[i].train( *samples );
    }
  }

  void write( FileStorage &fs ) const
  {
    fs << "ntrees" << T << "trees"
       << "[";
    for ( int i = 0; i < T; ++i )
    {
      fs << "{";
      tree[i].write( fs );
      fs << "}";
    }
    fs << "]";
  }

  void read( const FileNode &fn )
  {
    CV_Assert( T == (int)fn["ntrees"] );
    FileNodeIterator it = fn["trees"].begin();
    for ( int i = 0; i < T; ++i, ++it )
      tree[i].read( *it );
  }

  static Ptr< GPCForest > create() { return makePtr< GPCForest >(); }
};
}

CV_EXPORTS void write( FileStorage &fs, const String &name, const optflow::GPCTree::Node &node );

CV_EXPORTS void read( const FileNode &fn, optflow::GPCTree::Node &node, optflow::GPCTree::Node );
}

#endif