How do I develop a pseudo Zernike Moments proposed by Al-Rawi, 2010?

Based on the file shared here : fast computation of PZM by Sadeq al-Rawi,how do I continue the work to compute the moments based on his proposed method (mentioned in the paper 'Fast computation of pseudo Zernike moments')? I'd tried to build full code but it give me poor performance (in term of accuracy) when I implement it into face recognition system. EDIT: MY CODE IS AS FOLLOW:

img1 = imread('exp.bmp');
N = 4; %order
img =double(img1);
S = size(img, 1);
xstep = 2/(S-1);

[X ,Y] = meshgrid(0:xstep:1,0:xstep:1);
Rd = sqrt((2.*X-S+1).^2+(S-1-2.*Y).^2)/S;
theta = atan((S-1-2.*Y)/ (2.*X-S+1));

Rd = (Rd<=1).*Rd;
imshow(Rd);
Rd =[Rd(:)];
theta =[theta(:)];

Rad = pseudo_zernike_radial_polynomials(N, Rd);

op =[];
vectr = [];
prodc = [];
PZm = [];
%algorithm 2 as in al-rawi, 2010
psi = [];
arc = atan((S/2-10)/(S-20));
a = S-20;
b = S/2-10;
na = 20;
nb = S/2+10;
ay = 20;
nay = S-20;
bx = S/2+10;
nbx = S/2-10;
for m=0:N
    if mod(m,2)==0
        x1  = img(a,b)+img(na, nb);
        x2 = img(a, nb) +img(na,b);
        y1 = ((-1)^m/2)*(img(nbx, ay)+img(bx, nay));
        y2 = ((-1)^m/2)*(img(bx, ay)+img(nbx, nay));
        psii = cos (m*arc)*(x1+y1+x2+y2)-1j*sin(m*arc)*(x1+y1-x2-y2);
    else
        x1  = img(a,b)-img(na, nb);
        x2 = img(a, nb) -img(na,b);
        y1 = ((-1)^m/2)*(img(nbx, ay)-img(bx, nay));
        y2 = ((-1)^m/2)*(img(bx, ay)-img(nbx, nay));
        psii = cos(m*arc)*(x1+x2)+sin(m*arc)*(y1-y2)+1j*(cos(m*arc)*(y1+y2)-sin(m*arc)*(x1-x2));
    end
    psi =[psi,psii]; 
end 
for ord = 0:N
    for lpsi =1:length(psi)
        prod = psi(lpsi).*Rad(ord+1,:)';
        prodc = [prodc, prod];
        PZmn = ((N+1)/pi)*sum(sum(prodc(:, ord+1)));
        PZm = [PZm; PZmn];
    end
end