eigenface.m

% Face Recognition using Independent Component Analysis (ICA)
% Created on Mar 2015
% Authors: Sid Ali Rezetane, Sina M. Baharlou, Harold Agudelo
% calculate the eigenvalues
% V is the matrix containing the eigen vectors
% E is the matrix containing the eigen values
function [V, E] = eigen(M)
 
    % calculate the size of the matrix
    m_size = size(M);
 
    % calculate the covariance
     c = 1 / (m_size(2) - 1) * (M'*M);%cov(M);
 
    % calculate the eigen vectors of M'
    [U, E] = eig(c);
 
    % sort eigen vectors
    [sorted_eig, index] = sort(sum(E));
    index = fliplr(index);
    sorted_eig = fliplr(sorted_eig);
    V = U(:, [index]);
 
    % calculate the eigen vectors for M
    V = M * V;
 
    % calcuate the eigen values
    E = sqrt(sum(V .^ 2));
 
    % normalize the eigenvectors
    V = V ./ (ones(m_size(1), 1) * E);
 
    E = sorted_eig;
 
end