function [rho_estime, N_estime] = estimation_non_calibree(I, masque)

    masque2 = logical(masque);

    [u, s, v] = svds(I(:, masque2(:)));

    u_bar = u(:,1:3);
    s_bar = s(1:3, 1:3);
    v_bar = v(:, 1:3);

    S0 = u_bar * s_bar.^(1/2);
    M0 = zeros(3, size(I, 2));
    M0(:, masque2(:)) = s_bar.^(1/2) * v_bar';

    M1 = impose_integrabilite(M0, masque2);

    A = M1 / M0;
    S1 = S0 / A;

    alpha = - mean(M1(1,:)) / mean(M1(3,:));
    beta = - mean(M1(2,:)) / mean(M1(3,:));

    min_var = +Inf;
    for gamma=0.1:0.01:1

        Ginv = [ 1 0 -alpha/gamma ; 0 1 -beta/gamma ; 0 0 1/gamma ];
        S = S1 * Ginv;

        [rho_estime_, N_estime_] = estimation(I, S, masque2);
        bidule = std(rho_estime_(:));

        if bidule < min_var
            min_var = bidule;
            rho_estime = rho_estime_;
            N_estime = N_estime_;
        end

    end

end