Fig. 9From: A new evaluation function for face image enhancement in unconstrained environments using metaheuristic algorithmsQualitative comparison of the different image enhancement algorithms on the AR face dataset where Figs. 1, 2, 3, 4, 5, and 6 represent images of different subjects respectively. a–j denote the methods labeled as a original, b LCC, c HE, d IIA, e M_PSO, f M_GA, g BDPFHE, h CLAHE, i LLIE, and j proposedBack to article page