Relative accuracy of the uυ-based parameter estimates, flux density, effective radius, axis ratio, and Sérsic index (from left to right) given by cr(para)/para. Here, σ(para) is the uncertainties of the parameter estimates distribution and is calculated as 1.48×MAD, as a function of the S/N of flux density. The top panels show the results derived from fits with an elliptical Gaussian (orange) and circular Gaussian (green) model, while the results from a Spergel model uυ fit with input R_e/θ_b of 0.1, 0.2, 0.4, and 0.7 are shown in panels from the second to fifth rows, respectively. We only display results for the cases with a Spergel index of 0.5 and −0.7 from our simulation. For other cases with a Spergel index between v = 0.5 and −0.7, the results were found to be within or close to those shown in the panels between the second and fifth rows. The dashed vertical lines represent the threshold of S _tot/σ_b of 50.