scaleif.m

function sim = scaleif(im, varargin)
%  function sim = scaleif(im, newMin, newMax, oldMin, oldMax)
%  Scales an image such that its lowest value attains newMin and
%  it’s highest value attains newMax.  OldMin and oldMax are not
%  necessary but are useful when you don't want to use the true
%  min or max value.
%
% Adapted by Ione Fine, based on code from Rick Anthony
% 6/5/2000

length(varargin)
if length(varargin)==0
    newMin=0;
    newMax=1;
    oldMin = min(im(:));
    oldMax = max(im(:));
elseif length(varargin)==2
    newMin=varargin{1};
    newMax=varargin{2};
    oldMin = min(im(:));
     oldMax = max(im(:));
elseif length(varargin)==4
    newMin=varargin{1};
    newMax=varargin{2};
    oldMin=varargin{3};
    oldMax=varargin{4};
else 
    disp('Wrong number of input arguments')
    sim=NaN;
    return
end

if (newMin>=newMax)
    disp('Sorry new min must be smaller than new max');
    sim=NaN;
    return
end

if (oldMin>=oldMax)
    disp('Sorry old min must be smaller than old max');
    sim=NaN;
    return
end


delta = (newMax-newMin)/(oldMax-oldMin);
sim = delta*(im-oldMin) + newMin;