Results of the realistic simulation (averaged over ten realisations to reduce the statistical uncertainty of the single simulation). Left: fitted visibility function. The red measurements show the simulated data, the red curve shows the fitted model, the dashed black curve shows the input model (Table 1) and the gray shaded area is the 1σ confidence interval. Right: trends of for the two measurements (blue and orange continuous curves) and of (S/N)_θ (red continuous curve) as a function of the integration time. The measured curves are compared to the theoretical predictions (dashed curves) from Eqs. (27) and (28).