Comparison of the different algorithms used here. The intensity scale was optimized to detect the fake companions. Ten individual companions have been simulated for the tests. Only five are displayed here. All presented images have undergone three iterations of the tested filtering algorithms. Left: wavelet algorithm used in this work. Upper-middle: 20 × 20 pixels Gaussian kernel filtering followed by 3 × 3 Gaussian smoothing to remove pixel noise. Lower-middle: 5 × 5 pixels Gaussian kernel filtering followed by 3 × 3 Gaussian smoothing to remove pixel noise. Upper-right: 20 × 20 pixels median filtering followed by 3 × 3 Gaussian smoothing to remove pixel noise. Lower-right: 5 × 5 pixels median filtering followed by 3 × 3 Gaussian smoothing to remove pixel noise.