Different quantities used to obtain an unbiased mean PS₀ of the fringe data (bottom-right panel) over the frames. The mean PS_dark (upper-right panel) removes the contribution of the dark (artifacts and background structures) in the mean PS₁ of the fringe (upper-left panel) and the mean PS_foreground of the foreground data (bottom-left panel). The mean PS_foreground removes the photon noise contribution and other background structures.