function u_barre = calcul_structure_2(u, b, Dx, Dy, lambda, epsilon)
    
    u_reshaped = reshape(u,[], 1);

    N = length(b);

    coeffs = 1 ./ sqrt( (Dx * u_reshaped).^2 + (Dy * u_reshaped).^2 + epsilon );

    W = spdiags(coeffs, 0, N, N);

    A = speye(N) + lambda * (Dx' * W * Dx + Dy' * W * Dy);

    u_barre = A \ b;

    u_barre = reshape(u_barre,size(u));

end