rsdl_borgefors.h

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#ifndef rsdl_borgefors_h_
#define rsdl_borgefors_h_

//:
// \file
// \brief templated borgefors distance map using 3-4 chamfer distance transform
// \author Charlene Tsai
// \date 5 May 2001
//
// Defines functions associated with a templated borgefors
// distance map. The data based on which the map is built is a vector
// (should be changed to any stl container type later) of any
// datatype with x() and y() functions defined.

#include <vcl_vector.h>
#include <vbl/vbl_array_2d.h>

//: Defines functions associated with a templated borgefors distance map.
//  The data based on which the map is built is a vector
//  (should be changed to any stl container type later) of any
//  datatype with x() and y() functions defined.
//
//  The computation of the distance map is done using 3-4 chamfer distance
//  transform.
//
//  CAVEAT:
//  To avoid data duplication, objects are stored as pointers in the map.
//  Classes having rsdl_borgefors as the internal data should recompute
//  the borgefors map when define the copy constructor and operator=
//  To enforce this, the copy constructor and the operator= of rsdl_borgefors
//  are not implemented and are private member functions to avoid default ones
//  being generated by the compiler.
//
template <class T>
class rsdl_borgefors
{
  typedef typename vcl_vector<T>::iterator iterator_type;
  typedef typename vcl_vector<T>::const_iterator const_iterator_type;

 public:
  //: default constructor
  rsdl_borgefors();
  //: constructor: constructs a distance map, with dimensions set by size_x and size_y
  rsdl_borgefors(int org_x, int org_y, int size_x, int size_y,
                 iterator_type begin, iterator_type end, bool release_dist_map = false);
  //: sets distance and index maps, with dimensions set by size_x and size_y
  //  \param org_x  x-coord of the top left corner
  //  \param org_y  y-coord of the top left corner
  //  \param size_x x dimension
  //  \param size_y y dimension
  //  \param begin  begin ptr of the data vector
  //  \param end    end ptr of the data vector
  //  \param release_dist_map should the distance map be released?
  void set(int org_x, int org_y, int size_x, int size_y,
           iterator_type begin, iterator_type end, bool release_dist_map = false);

  //: sets all data members from the caller
  //  \param org_x  x-coord of the top left corner
  //  \param org_y  y-coord of the top left corner
  //  \param size_x x dimension
  //  \param size_y y dimension
  //  \param begin  begin ptr of the data vector
  //  \param end    end ptr of the data vector
  //  \param index_map    index map
  //  \param distance_map distance map
  void set(int org_x, int org_y, int size_x, int size_y,
           iterator_type begin, iterator_type end,
           vbl_array_2d<int> index_map,
           vbl_array_2d<int>* distance_map = 0 );

  //: resets the data members
  void reset();
  //: returns true if the map contains valid data
  bool is_valid() const {return is_valid_;}

  //: returns approximated distance to between (x,y) and closest object in the map
  double distance(int x, int y) const;
  //: verifies if (x,y) position is valid in the map
  bool in_map(int x, int y) const;
  //: returns a pointer to the closest object to (x,y) in the map
  //  It aborts if (x,y) not in map. Should always check in_map(x,y) first.
  const_iterator_type nearest(int x, int y) const;

  //: returns width of the map
  int width() const {return size_x_; }
  //: returns height of the map
  int height()const {return  size_y_; }

  //: returns origin of the map
  void origin(int& start_x, int& start_y) const;

  const vbl_array_2d<int>& distance_map() const {return distance_map_; }
  const vbl_array_2d<int>& index_map() const {return index_map_; }

  //: equality (comparison) operator
  bool operator== (const rsdl_borgefors<T> & rhs) const;

 private:
  //: copy constructor, not implemented
  rsdl_borgefors(const rsdl_borgefors<T>& old);
  //: assignment operator, not implemented
  rsdl_borgefors<T>& operator=(const rsdl_borgefors<T>& rhs);

  void initialize(iterator_type  begin, iterator_type end);
  void chamfer34();
  void forward_chamfer();
  void backward_chamfer();
  int minimum4(int,int,int,int) const;
  int minimum5(int,int,int,int,int) const;

 private:
  bool is_valid_;
  int org_x_, org_y_, size_x_, size_y_;
  vbl_array_2d<int> distance_map_;
  vbl_array_2d<int> index_map_;
  vcl_vector<iterator_type> data_;
};

#endif // rsdl_borgefors_h_

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