% Example 2.9b from Digital Signal and Image Processing
% Tamal Bose
% Plot the inverse 2-D DTFT of circularly symmetric low-pass filter
w1=[-10:1:10];
w2=[-10:1:10];
for n=1:max(size(w1))
   for m=1:length(w2)
       f(n,m)=(besselj(1,((pi/1.5)*sqrt(w1(n)^2+w2(m)^2)))+eps)/(3*sqrt(w1(n)^2+w2(m)^2)+eps);
   end
end
surf(w1,w2,f)
colormap hsv
colorbar
xlabel('n1');
ylabel('n2');
zlabel('Magnitude of h(n_1,n_2)');
title('Plot of impulse response of h(n_1,n_2)');