function h = zucker(nhsize, orientation)
% zucker's line detecor
if nhsize < 25,
   tau1 = 1.14;
   tau2 = 1.8;
   tau3 = 2.28;
   tauy = 3.6;
   B = 1.266;
   C = 0.5;
   [x,y] = meshgrid(-7:1:7,-7:1:7);
else
   tau1 = 1.9;
   tau2 = 3.0;
   tau3 = 3.8;
   tauy = 6.0;
   B = 1.266;
   C = 0.5;
   [x,y] = meshgrid(-12:1:12,-12:1:12);
end;
rx = (x * cos(orientation)) + (y *sin(orientation));
ry = -x * sin(orientation) + y * cos(orientation);
h = (exp(-rx.*rx/tau1^2) - B*exp(-rx.*rx/tau2^2) + C * exp(-rx.*rx/tau3^2)) .* exp(-ry.*ry/tauy^2);
h = h - sum(sum(h))/(size(h,1)*size(h,2));
end

return

