function f = compute_gaussian_filter(n,s,N);

% compute_gaussian_filter - compute a 1D or 2D Gaussian filter.
%
%   f = compute_gaussian_filter(n,s,N);
%
%   'n' is the size of the filter, odd for no phase in the filter.
%       (if too small it will alterate the filter).
%       use n=[n1,n2] for a 2D filter
%   's' is the standard deviation of the filter.
%   'N' is the size of the big signal/image (supposed to lie in [0,1] or [0,1]x[0,1]).
%       use N=[N1,N2] for a 2D filter.
%
%   The equation (in 1D) is
%       f[k] = exp( -(x(k)^2/(2*s^2)) );
%   where x span [-1/2,1/2].
%
%   The filter is normalised so that it sums to 1.
%
%   Copyright (c) 2004 Gabriel Peyr