Figure 21

(a) and (b) Lena and Peppers watermarked images with 256 × 256 watermark image as shown in Figure 11(b) after Sharpening, (e) and (f) the extracted watermarks with size 256 × 256 from (a) and (b), respectively. (c) and (d) Crowd and Baboon watermarked images with 128 × 128 watermark image as shown in Figure 11(b) after Sharpening, (g) and (h) the extracted watermarks with size 128 × 128 from (c) and (d), respectively. (i) and (j) Lena and Peppers watermarked images with 128 × 128 watermark image as shown in Figure 11(d) after Sharpening, (m) and (n) the extracted watermarks with size 128 × 128 from (i) and (j), respectively. (k) and (l) Crowd and Baboon watermarked images with 256 × 256 watermark image as shown in Figure 11(d) after Sharpening, (o) and (p) the extracted watermarks with size 256 × 256 from (k) and (l), respectively. (a)PSNR = 25.34 dB (b)PSNR = 25.15 dB (c)PSNR = 23.28 dB (d)PSNR = 21.10 dB (e)γ = 0.7308 (f)γ = 0.7144 (g)γ = 0.6174 (h)γ = 0.5034 (i)PSNR = 25.39 dB (j)PSNR = 25.20 dB (k)PSNR = 23.27 dB (l)PSNR = 21.08 dB (m)γ = 0.6679 (n)γ = 0.6684 (o)γ = 0.3421 (p)γ = 0.4626