Figure 2. Estimation of initial phase ϕ_j by correlating the reconstruction I_SIM,j and the wide-field.

(a) The R₂(Φ) curve provides the values of the normalized cross-correlation between the wide-field and the reconstruction I_SIM,2 at different phases from 0 to 2π. Arguments of the maximum and minimum of the curve respectively determine the best and worst estimates of the initial phase. I_SIM,2 reconstruction with (b) 2π/3 and (c) 5π/3. Taking the former as reference it is clear that the latter is full of artifacts. Magnifications of the area within the white rectangle: Reconstructions using different initial phase values (d) 2π/3, (e) 0 and (f) 5π/3. The degradation of the reconstruction seems gradual, from the best result in (d), then to a stage of moderate artifact occurrence in (e) and finally severe distortions in (f).