S/N of R CrA b as a function of the number of components used. The solid black line corresponds to the S/N from the data reduction presented in Cugno et al. (2019). The thin solid lines correspond to the full dataset. The thick transparent lines correspond to the reduction with frame selection using ϕ equal to 1 (orange), 0.5 (pink), and 0.25 (cyan). For all the reductions, ρ = 0.5. In the left panel the frames are processed using the star position as the reference center for the full analysis. The middle panel shows the results when using the AGPM position for the principal component analysis and the star position for the derotation and stacking of the frames. In the right panel the center is located at the position of the AGPM for the full analysis.