function image = zoneImage() 
% test image

xx = 1:512;
yy = 1:512;
[x,y] = meshgrid(xx, yy);
d = sqrt((x-256).^2+(y-256).^2);
%d = sqrt(x.*y);
image = cos(d.*(d*pi/256/2/sqrt(2)))/2+0.5;
image = image .* [d < 256];
