--- /dev/null
+## Copyright (C) 1999,2000 Kai Habel
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} @var{I}= mat2gray (@var{M},[min max])
+## Converts a matrix to a intensity image.
+## @end deftypefn
+
+## Author: Kai Habel <kai.habel@gmx.de>
+## Date: 22/03/2000
+
+function I = mat2gray (M, scale)
+
+ if (nargin < 1|| nargin > 2)
+ usage ("mat2gray(...) number of arguments must be 1 or 2");
+ endif
+
+ if (!ismatrix (M))
+ usage ("mat2gray(M,...) M must be a matrix");
+ endif
+
+ if (nargin == 1)
+ Mmin = min (min (M));
+ Mmax = max (max (M));
+ else
+ if (isvector (scale))
+ Mmin = min (scale (1), scale (2));
+ Mmax = max (scale (1), scale (2));
+ endif
+ endif
+
+ I = (M < Mmin) .* 0;
+ I = I + (M >= Mmin & M < Mmax) .* (1 / (Mmax - Mmin) * (M - Mmin));
+ I = I + (M >= Mmax);
+
+endfunction