Standard test images used in the experiments: (a) Barbara; (b) Boat; (c) Cameraman; (d) Car; (e) Clown; (f) Couple; (g) Crowd; (h) Einstein; (i) Girlface; (j) Goldhill; (k) Lena; (l) Baboon; (m) Office; (n) Peppers; (o) Pirate; (p) Street; (q) Town; (r) ...