--- milena/ChangeLog | 4 ++++ milena/mln/histo/equalize.hh | 24 +++++++++++++++++------- 2 files changed, 21 insertions(+), 7 deletions(-) diff --git a/milena/ChangeLog b/milena/ChangeLog index a9f96d8..d9f0ffa 100644 --- a/milena/ChangeLog +++ b/milena/ChangeLog @@ -1,5 +1,9 @@ 2012-11-13 Guillaume Lazzara <z@lrde.epita.fr> + * mln/histo/equalize.hh: Fix. + +2012-11-13 Guillaume Lazzara <z@lrde.epita.fr> + * mln/histo/equalize.hh: Revamp. 2012-08-23 Guillaume Lazzara <z@lrde.epita.fr> diff --git a/milena/mln/histo/equalize.hh b/milena/mln/histo/equalize.hh index d1de0e9..7f994df 100644 --- a/milena/mln/histo/equalize.hh +++ b/milena/mln/histo/equalize.hh @@ -27,6 +27,7 @@ #ifndef MLN_HISTO_EQUALIZE_HH # define MLN_HISTO_EQUALIZE_HH +# include <cmath> # include <mln/core/concept/image.hh> # include <mln/histo/all.hh> @@ -43,6 +44,9 @@ namespace mln /*! \brief Equalizes the histogram of image \p input. \author J. Fabrizio, R. Levillain + + Source: + http://en.wikipedia.org/wiki/Histogram_equalization */ template <typename I> mln_concrete(I) equalize(const Image<I>& input); @@ -63,19 +67,25 @@ namespace mln array<V> histogram = compute(input); array<V> histo_correction; - unsigned cumulation = 0; - unsigned number_of_pixels = input.nsites(); - //int number_of_colors=histogram.nvalues(); - //int number_of_colors=mln_card(V); + unsigned nsites = input.nsites(); V max_color = mln_max(V); + unsigned h_min = nsites; mln_viter(mln::value::set<V>) v(histogram.vset()); + + // Looking for minimum occurence in histogram + for_all(v) + if (histogram(v) > 0 && h_min > histogram(v)) + h_min = histogram(v); + + // Computing new histogram. + unsigned cdf_v = 0; for_all(v) if (histogram(v) != 0) { - cumulation += histogram(v); - histo_correction(v) = (/*number_of_colors-1*/max_color) - * cumulation / number_of_pixels; + cdf_v += histogram(v); + histo_correction(v) + = round((cdf_v - h_min) / (float)(nsites - h_min) * max_color); } mln_concrete(I) output; -- 1.7.2.5