Graphical representation of the detector response matrices for three different collision systems: pp (a), p$-$Pb (b) and Pb$-$p (c). The reconstructed and true photon multiplicities are denoted as $N_{\gamma\text-\rm like}$ and $N_{\gamma\text-\rm true}$, respectively, obtained from simulations using PYTHIA 8 with the Monash 2013 tune for pp collisions and Hijing for p$-$Pb and Pb$-$p collisions.