A Robust Fractal Color Image Watermarking Algorithm

Table 3

Extracted watermarks (EW) and NCs after attacked by Gaussian noise added from 𝜎=5 to 10, and to 15, scaling with factor 2, and various cropping to the original size of the three images.

	Gaussian noise			Cropping (Figure 7)			Scaling; (factor 2)
	𝜎=5	𝜎=10	𝜎=15	I	II	III
Lena
EW
NC	0.9803	0.8225	0.6276	0.6997	0.6075	0.7957	0.9633
Barbara
EW
NC	0.9148	0.7429	0.5657	0.7086	0.5800	0.7463	0.9767
Peppers
EW
NC	0.9010	0.7024	0.5280	0.6959	0.5665	0.7396	0.9480