gistfile1.txt

  case 'log' % Laplacian of Gaussian
     % first calculate Gaussian
     siz   = (p2-1)/2;
     std2   = p3^2;
     
     [x,y] = meshgrid(-siz(2):siz(2),-siz(1):siz(1));
     arg   = -(x.*x + y.*y)/(2*std2);
     
     h     = exp(arg);
     h(h<eps*max(h(:))) = 0;

     sumh = sum(h(:));
     if sumh ~= 0,
       h  = h/sumh;
     end;
     % now calculate Laplacian     
     h1 = h.*(x.*x + y.*y - 2*std2)/(std2^2);
     h     = h1 - sum(h1(:))/prod(p2); % make the filter sum to zero
     
     
  case 'gaussian' % Gaussian filter

     siz   = (p2-1)/2;
     std   = p3;
     
     [x,y] = meshgrid(-siz(2):siz(2),-siz(1):siz(1));
     arg   = -(x.*x + y.*y)/(2*std*std);

     h     = exp(arg);
     h(h<eps*max(h(:))) = 0;

     sumh = sum(h(:));
     if sumh ~= 0,
       h  = h/sumh;
     end;