480274.fig.004a
(a)
480274.fig.004b
(b)
480274.fig.004c
(c)
480274.fig.004d
(d)
Figure 4: Comparison of noise detectors for 20% random-valued impulse noise corrupted image of Lena: (a) ROAD; (b) ROLD; (c) RORD; (d) DARD.