function output_image = scale( input_image )
% output_image = scale( input_image )
%
% scales image to range [0,1]

% make all image values E [0, high-low]
low = min(min(input_image));
output_image = input_image - low;

% make all image values E [0, 1]
high = max(max(output_image));
output_image = output_image ./ high;