function [m, A, Eigenfaces] = EigenfaceCore(T)
m = mean(T,2); 
Train_Number = size(T,2);


A = [];  
for i = 1 : Train_Number
    temp = double(T(:,i)) - m;
    A = [A temp]; % Merging all centered images
end



L = A'*A;
[V D] = eig(L);


L_eig_vec = [];
for i = 1 : size(V,2) 
    if( D(i,i)>1 )
        L_eig_vec = [L_eig_vec V(:,i)];
    end
end

Eigenfaces = A * L_eig_vec; % A: centered image vectors