scale_image.m

function imo = scale_image(im, vlow, vhigh, ilow, ihigh)
% linearly scale the input image IM to the range [vlow, vhigh]
% from the range [ilow ihigh] (if provided)
%
% Authors: Deqing Sun, Department of Computer Science, Brown University 
% Contact: dqsun@cs.brown.edu
% $Date: $
% $Revision: $
%
% Copyright 2007-2010, Brown University, Providence, RI. USA
% 
%                          All Rights Reserved
% 
% All commercial use of this software, whether direct or indirect, is
% strictly prohibited including, without limitation, incorporation into in
% a commercial product, use in a commercial service, or production of other
% artifacts for commercial purposes.     
%
% Permission to use, copy, modify, and distribute this software and its
% documentation for research purposes is hereby granted without fee,
% provided that the above copyright notice appears in all copies and that
% both that copyright notice and this permission notice appear in
% supporting documentation, and that the name of the author and Brown
% University not be used in advertising or publicity pertaining to
% distribution of the software without specific, written prior permission.        
%
% For commercial uses contact the Technology Venture Office of Brown University
% 
% THE AUTHOR AND BROWN UNIVERSITY DISCLAIM ALL WARRANTIES WITH REGARD TO
% THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
% FITNESS FOR ANY PARTICULAR PURPOSE.  IN NO EVENT SHALL THE AUTHOR OR
% BROWN UNIVERSITY BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
% DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
% PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
% ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
% THIS SOFTWARE.         

if nargin == 3
    ilow    = min(im(:));
    ihigh   = max(im(:));
end;

imo = (im-ilow)/(ihigh-ilow) * (vhigh-vlow) + vlow;