function g = delsqG(s,K)
%  g = gauss(s,K)
%      s is sigma
%      K is window size of Gaussian convolution kernel
k = (K-1)/2;
g = zeros(K,K);
s2 = 2*s^2;
for ii = -k:k
  for jj = -k:k
    g(k+1+ii,k+1+jj) = exp(-((ii^2+jj^2)/s2));
  end
end
