Dependence of the reconstructions on (a) the regularization functions H [o_k(x)] used and (b) the χ² function Q [o_k(x)] applied in the cost function. This study shows reconstructions of the 16.8 mas disk-star target obtained in the experiment, as shown in Fig. 1 (for average S/N ~ 9 of the squared visibilities). Each row presents the reconstructions performed with one of the five regularization functions (RG1, RG2, RG3, RG4, and RG4b; see text and Eqs. (7)–(10)). The first two columns are reconstructions using the χ² function Q₁ [o_k(x)] (see Eq. (4)) and the last two columns are reconstructions with the χ² function Q₂ [o_k(x)] (see Eq. (5)). The columns labeled with “best q_rec” are the reconstructions with the smallest value of q_rec and those labeled with “best ρ” are the reconstructions with the smallest distance to the theoretical target. In each image, its restoration error ρ and its value of the reconstruction quality parameter q_rec is presented.