Total correction (efficiency and acceptance) for $|y|< 0.5$ for ${\rm \pi^0}$ reconstruction via two-photon invariant mass determination in pp collisions at $\sqrt{s}$ = 7 TeV (top panel) and in 0-10% central Pb-Pb collisions at $\sNN$ = 2.76 TeV (bottom panel) for PCM, PHOS, and EMCal.