Normalized azimuthal standard deviation profiles before (plain line) and after (dashed line) correction of the NCPA using ZELDA, as a function of angular separation. The contrast gain is plotted in the bottom panel. The dotted line corresponds to the edge of the coronagraphic mask (90 mas). The measurements correspond to the coronagraphic images presented in Fig. 9. They are compared to the theoretical performance of the SPHERE APLC (red, dash-dotted line).