173931.fig.004a
(a) Original image: Lena
173931.fig.004b
(b) Encrypted image: Lena
173931.fig.004c
(c) Original image: Black
173931.fig.004d
(d) Encrypted image: Black
173931.fig.004e
(e) Original image: Baboon
173931.fig.004f
(f) Encrypted image: Baboon
173931.fig.004g
(g) Original image: Checkerboard
173931.fig.004h
(h) Encrypted image: Checkerboard
Figure 4: Histograms of original and encrypted images.