S/N retrieved with cADI of 5σ injection. The injected 5σ signal at each position comes from the TRAP 5σ map of the Altair dataset. Left panel: retrieved S/N map with cADI. The injected region is from 412 to 792 mas. The stronger detection at the inner part of the dark region is due to the higher false alarm probabilities caused by small sample statistics (Mawet et al. 2014). Only a small number of pixels are available for normalisation at small separations, and therefore the uncertainty is underestimated. Right panel: S/N histogram of the left panel. The blue line depicts the profile of the dark region with a median S/N of 2.5 and the orange line depicts of the profile of the transition region with a median S/N of 0.9.