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niblack_threshold_functor.hh
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26 
27 #ifndef SCRIBO_BINARIZATION_INTERNAL_NIBLACK_THRESHOLD_FUNCTOR_HH
28 # define SCRIBO_BINARIZATION_INTERNAL_NIBLACK_THRESHOLD_FUNCTOR_HH
29 
33 
34 # include <mln/core/image/image2d.hh>
35 # include <mln/core/alias/neighb2d.hh>
36 # include <mln/extension/fill.hh>
37 
38 # include <scribo/binarization/internal/niblack_formula.hh>
39 
40 # ifdef SCRIBO_LOCAL_THRESHOLD_DEBUG
41 # include <scribo/binarization/internal/local_threshold_debug.hh>
42 # endif // ! SCRIBO_LOCAL_THRESHOLD_DEBUG
43 
44 
45 namespace scribo
46 {
47 
48  namespace binarization
49  {
50 
51  namespace internal
52  {
53 
54  using namespace mln;
55 
56 
57  template <typename I>
59  {
60  // Moves in input and output images are made using "step"
61  // pixels. It corresponds to the scale ratio between the input
62  // image and the integral image used to give the statistics
63  // values.
64  enum { step = 3 };
65 
67  double K);
68 
69  void init();
70 
71  // Run every 4 pixels.
72  void exec(double mean, double stddev);
73 
74  void end_of_row(int);
75 
76  void finalize();
77 
78  typedef mln_concrete(I) th_t;
79  th_t output;
80  mln_concrete(I) input;
81 
82  mln_value(I)* po;
83 
84  double K_;
85 
87 
88  unsigned next_line3;
89  unsigned offset1;
90  unsigned offset2;
91  };
92 
93 #ifndef MLN_INCLUDE_ONLY
94 
95  template <typename I>
97  double K)
98  : input(input_),
99  K_(K)
100  {
101  mln_precondition(exact(input_).is_valid());
102  mln_precondition(K > 0.);
103  }
104 
105  template <typename I>
106  void
107  niblack_threshold_functor<I>::init()
108  {
109  // This initialization MUST be done here since input image
110  // borders may have changed!
111  next_line3 = input.delta_offset(dpoint2d(+2,0)) + 2 * input.border() - 1;
112 
113  offset1 = input.delta_offset(dpoint2d(+1,0));
114  offset2 = input.delta_offset(dpoint2d(+2,0));
115 
116  initialize(output, input);
117  po = &output(output.domain().pmin());
118  }
119 
120  template <typename I>
121  void
122  niblack_threshold_functor<I>::exec(double mean, double stddev)
123  {
124  mln_assertion(input.border() == output.border());
125  static point2d p(0,0);
126 
127  typedef mln_value(I) V;
128  V th = static_cast<V>(formula_(mean, stddev, K_));
129 
130  for (int i = 0; i < step; ++i, ++po)
131  {
132  *po = th;
133  *(po + offset1) = th;
134  *(po + offset2) = th;
135  }
136 
137 # ifdef SCRIBO_LOCAL_THRESHOLD_DEBUG
138  // Store local mean
139  unsigned index = po - output.buffer();
140 
141  internal::debug_mean.element(index) = mean * internal::mean_debug_factor;
142  internal::debug_stddev.element(index) = stddev * internal::stddev_debug_factor;
143  internal::debug_threshold.element(index) = t;
144 # endif // ! SCRIBO_LOCAL_THRESHOLD_DEBUG
145 
146  }
147 
148  template <typename I>
149  void
150  niblack_threshold_functor<I>::end_of_row(int)
151  {
152  po += next_line3;
153  }
154 
155  template <typename I>
156  void
157  niblack_threshold_functor<I>::finalize()
158  {
159  }
160 
161 #endif // ! MLN_INCLUDE_ONLY
162 
163  } // end of namespace scribo::binarization::internal
164 
165  } // end of namespace scribo::binarization
166 
167 } // end of namespace scribo
168 
169 #endif // SCRIBO_BINARIZATION_INTERNAL_NIBLACK_THRESHOLD_FUNCTOR_HH