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sauvola_formula.hh
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26 
27 #ifndef SCRIBO_BINARIZATION_INTERNAL_SAUVOLA_FORMULA_HH
28 # define SCRIBO_BINARIZATION_INTERNAL_SAUVOLA_FORMULA_HH
29 
30 
35 
36 
37 // Setup default Sauvola's formula parameters values.
38 // These macros may be used in other variant of Sauvola's algorithms.
39 //
40 // Values are set according to the following reference: "Automatic
41 // Evaluation of Document Binarization Results", Badekas and al, 2005
42 //
43 // Badekas et al. said 0.34 was best for Sauvola.
44 # define SCRIBO_DEFAULT_SAUVOLA_K 0.34
45 //
46 // 128 is best for grayscale documents.
47 # define SCRIBO_DEFAULT_SAUVOLA_R 128
48 
49 
50 #include <mln/core/alias/point2d.hh>
51 
52 namespace scribo
53 {
54 
55  namespace binarization
56  {
57 
58  namespace internal
59  {
60 
61  using namespace mln;
62 
64  {
65 
78  double operator()(const double m_x_y, const double s_x_y,
79  const double K, const double R) const;
80 
85  double operator()(const double m_x_y, const double s_x_y) const;
86 
87  };
88 
89 
90 # ifndef MLN_INCLUDE_ONLY
91 
92  inline
93  double
94  sauvola_formula::operator()(const double m_x_y, const double s_x_y,
95  const double K, const double R) const
96  {
97  return m_x_y * (1.0 + K * ((s_x_y / R) - 1.0));
98  }
99 
100  inline
101  double
102  sauvola_formula::operator()(const double m_x_y, const double s_x_y) const
103  {
104  return (*this)(m_x_y, s_x_y,
105  SCRIBO_DEFAULT_SAUVOLA_K, SCRIBO_DEFAULT_SAUVOLA_R);
106  }
107 
108 # endif // ! MLN_INCLUDE_ONLY
109 
110  } // end of namespace scribo::binarization::internal
111 
112  } // end of namespace scribo::binarization
113 
114 } // end of namespace scribo
115 
116 #endif // ! SCRIBO_BINARIZATION_INTERNAL_SAUVOLA_FORMULA_HH