Noise measured on the LS for each slope along the elongated axis (first 36 slopes) and the thin axis (last 36 slopes) for one acquisition in sequences 5, 10, and 15 (left to right). The blue curves show the noise values obtained when projecting the slopes on the elongated and thin axes of the spot, the orange dashed curves show the values obtained when computing the eigenvalues of the covariance matrix .