Mercurial > hg > octave-image

changeset 276:e7355884e532 release-1.0.5

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Actually use the number of bins, and scale the matrix to 0..1 range before using it (For Jonas Wagner)
author adb014
date Mon, 11 Feb 2008 09:28:14 +0000
parents 2c020edd905e
children 02b11f5cf655
files inst/histeq.m
diffstat 1 files changed, 14 insertions(+), 6 deletions(-) [+]
line wrap: on
line diff
--- a/inst/histeq.m
+++ b/inst/histeq.m
@@ -14,14 +14,20 @@
 ## along with this program; If not, see <http://www.gnu.org/licenses/>.
 
 ## -*- texinfo -*-
-## @deftypefn {Function File} @var{J}= histeq (@var{I}, @var{n})
+## @deftypefn {Function File} @var{J} = histeq (@var{I}, @var{n})
 ## Histogram equalization of a gray-scale image. The histogram contains
 ## @var{n} bins, which defaults to 64.
+##
+## @var{I}: Image in double format, with values from 0.0 to 1.0
+##
+## @var{J}: Returned image, in double format as well
 ## @seealso{imhist}
 ## @end deftypefn
 
 ## Author:	Kai Habel <kai.habel@gmx.de>
 ## Date:	08. August 2000
+## Modified-by: Jonas Wagner <j.b.w@gmx.ch>
+## Date:        11. February 2008
 
 function J = histeq (I, n)
   if (nargin == 0)
@@ -30,10 +36,12 @@
     n = 64;
   endif
 
-  [r,c] = size (I); 
-  [X,map] = gray2ind(I);
-  [nn,xx] = imhist(I);
-  Icdf = ceil (n * cumsum (1/prod(size(I)) * nn));
+  [r,c] = size(I); 
+  I = mat2gray(I);
+  [X,map] = gray2ind(I, n);
+  [nn,xx] = imhist(I, n);
+  Icdf = 1 / prod(size(I)) * cumsum(nn);
   J = reshape(Icdf(X),r,c);
-  plot(Icdf,'b;;');
+  plot(Icdf,'b');
+  legend( 'Image Cumulative Density Function');
 endfunction