Go to the documentation of this file.00001 #ifndef bsta_otsu_threshold_txx_
00002 #define bsta_otsu_threshold_txx_
00003
00004 #include "bsta_otsu_threshold.h"
00005
00006 template <class T>
00007 bsta_otsu_threshold<T>::bsta_otsu_threshold(bsta_histogram<T> const& hist)
00008 : distribution_1d_(hist)
00009 {
00010 }
00011
00012 template <class T>
00013 bsta_otsu_threshold<T>::bsta_otsu_threshold(vcl_vector<T> data, T low , T high)
00014 :distribution_1d_(low,high,data)
00015 {
00016 }
00017
00018 template <class T>
00019 bsta_otsu_threshold<T>::~bsta_otsu_threshold()
00020 {
00021 }
00022
00023 template <class T>
00024 unsigned bsta_otsu_threshold<T>::bin_threshold() const
00025 {
00026 T no_of_pixels_in_class1=0;
00027 int threshold =0;
00028 T max_between_class_variance=0;
00029 T no_of_pixels_in_class2 = distribution_1d_.area();
00030
00031 for (unsigned t=0; t<distribution_1d_.nbins(); ++t)
00032 {
00033 T mu1 = distribution_1d_.mean(0, t);
00034 T mu2 = distribution_1d_.mean(t, distribution_1d_.nbins()-1);
00035
00036 T between_class_variance=no_of_pixels_in_class1*no_of_pixels_in_class2*
00037 (mu1-mu2)*(mu1-mu2);
00038
00039 if (between_class_variance>max_between_class_variance)
00040 {
00041 max_between_class_variance=between_class_variance;
00042 threshold=t;
00043 }
00044 no_of_pixels_in_class1+=distribution_1d_.counts(t);
00045 no_of_pixels_in_class2-=distribution_1d_.counts(t);
00046 }
00047
00048 return threshold;
00049 }
00050
00051 #undef BSTA_OTSU_THRESHOLD_INSTANTIATE
00052 #define BSTA_OTSU_THRESHOLD_INSTANTIATE(T) \
00053 template class bsta_otsu_threshold<T >
00054
00055 #endif // bsta_otsu_threshold_txx_
