median.hh 4.25 KB
Newer Older
Thierry Geraud's avatar
Thierry Geraud committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
// Copyright (C) 2007 EPITA Research and Development Laboratory
//
// This file is part of the Olena Library.  This library is free
// software; you can redistribute it and/or modify it under the terms
// of the GNU General Public License version 2 as published by the
// Free Software Foundation.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this library; see the file COPYING.  If not, write to
// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
// Boston, MA 02111-1307, USA.
//
// As a special exception, you may use this file as part of a free
// software library without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to
// produce an executable, this file does not by itself cause the
// resulting executable to be covered by the GNU General Public
// License.  This exception does not however invalidate any other
// reasons why the executable file might be covered by the GNU General
// Public License.

#ifndef MLN_LEVEL_MEDIAN_HH
# define MLN_LEVEL_MEDIAN_HH

/*! \file mln/level/median.hh
 *
33
 * \brief Median filtering of an image.
Thierry Geraud's avatar
Thierry Geraud committed
34
35
36
37
38
39
40
41
42
43
44
45
46
 */

# include <mln/core/concept/image.hh>
# include <mln/core/window2d.hh>
# include <mln/accu/median.hh>


namespace mln
{

  namespace level
  {

47
48
    /*! Compute in \p output the median filter of image \p input by
     *  the window \p win.
Thierry Geraud's avatar
Thierry Geraud committed
49
50
51
52
53
     *
     * \param[in] input The image to be filtered.
     * \param[in] win The window.
     * \param[in,out] output The output image.
     *
54
     * \pre \p input and \p output have to be initialized.
Thierry Geraud's avatar
Thierry Geraud committed
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
     */
    template <typename I, typename W, typename O>
    void median(const Image<I>& input, const Window<W>& win,
		Image<O>& output);


# ifndef MLN_INCLUDE_ONLY


    namespace impl
    {

      template <typename I, typename W, typename O>
      void median(const I& input,
		  const W& win,
		  O& output)
      {
72
73
74
75
76
77
	mln_precondition(input.has_data());
	mln_precondition(output.has_data());

	int
	  min_row = input.min_row(), max_row = input.max_row(),
	  min_col = input.min_col(), max_col = input.max_col();
Thierry Geraud's avatar
Thierry Geraud committed
78
79

	window2d
80
81
82
83
84
85
86
87
88
89
90
91
	  win_fwd_plus  = win - (win + left),
	  win_fwd_minus = (win + left) - win,
	  win_bkd_plus  = win - (win + right),
	  win_bkd_minus = (win + right) - win,
	  win_bot  = win - (win + up),
	  win_top = (win + up) - win;

	point2d p;
	mln_qiter(W)
	  q_fp(win_fwd_plus, p), q_fm(win_fwd_minus, p),
	  q_bp(win_bkd_plus, p), q_bm(win_bkd_minus, p),
	  q_top(win_top, p), q_bot(win_bot, p);
Thierry Geraud's avatar
Thierry Geraud committed
92
93
94
	
	accu::median_on<mln_value(I)> med;

95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
	// initialization

	p = input.domain().pmin() + up;
	med.init();
	{
	  mln_qiter(W) q(win, p);
	  for_all(q) if (input.has(q))
	    med.take(input(q));
	}

	int& row = p.row();
	int& col = p.col();
	bool fwd = true;

	mln_assertion(p.col() == min_col);
	mln_assertion(p.row() == min_row - 1);
Thierry Geraud's avatar
Thierry Geraud committed
111

112
	for (row = min_row; row <= max_row; ++row)
Thierry Geraud's avatar
Thierry Geraud committed
113
	  {
114
115
116
117
118
	    // "go down"
	    for_all(q_top) if (input.has(q_top))
	      med.untake(input(q_top));
	    for_all(q_bot) if (input.has(q_bot))
	      med.take(input(q_bot));
Thierry Geraud's avatar
Thierry Geraud committed
119
120
	    output(p) = med;

121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
	    if (fwd)
	      // browse line fwd
	      while (col < max_col)
		{
		  ++col;
		  for_all(q_fm) if (input.has(q_fm))
		    med.untake(input(q_fm));
		  for_all(q_fp) if (input.has(q_fp))
		    med.take(input(q_fp));
		  output(p) = med;
		}
	    else
	      // browse line bkd
	      while (col > min_col)
		{
		  --col;
		  for_all(q_bm) if (input.has(q_bm))
		    med.untake(input(q_bm));
		  for_all(q_bp) if (input.has(q_bp))
		    med.take(input(q_bp));
		  output(p) = med;
		}

	    // change browsing
	    fwd = ! fwd;
Thierry Geraud's avatar
Thierry Geraud committed
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
	  }
      }

    } // end of namespace mln::level::impl


    // facade

    template <typename I, typename W, typename O>
    void median(const Image<I>& input, const Window<W>& win,
		Image<O>& output)
    {
      impl::median(exact(input), exact(win), exact(output)); 
    }

# endif // ! MLN_INCLUDE_ONLY

  } // end of namespace mln::level

} // end of namespace mln


#endif // ! MLN_LEVEL_MEDIAN_HH