Reconstructed magnetic field lines for different models. (a) Artificial magnetogram in line-of-sight view. The color bar shows the strength (in Gauss) and polarity of the magnetic field. The reconstructed magnetic field lines are plotted for (b) the L&L semi-analytical solution, (c) the potential field, (d) theWSR optimization models, (e) the COS and (f) COV models without the weighting function, (g) the OWF optimization model, and (h) the COS and (i) COV models with a weighting function.