Histograms for the original longitudinal component of the magnetic field used in the synthesis of the simulated data (black). The retrieved distributions from the inversion are indicated by the color lines: SNR ≥ 3 (red), SNR ≥ 4.5 (green) and SNR ≥ 6 (blue). The CoG of the retrieved histograms are indicated by the vertical dashed lines. Each panel shows the results for different levels of noise: σ_s = 10^-3 (as in observed map A; upper-left), σ_s = 7.5 × 10^-4 (as in observed map B; upper-right), σ_s = 2.8 × 10^-4 (as in observed map C; lower-left), and finally σ_s = 10^-5.