A Polar Complex Exponential Transform-Based Zero-Watermarking for Multiple Medical Images with High Discrimination

Table 7

Resistance comparison against image filtering (BER).

Attack type	Proposed scheme			Scheme [19]	Scheme [20]	Scheme [24]
	1 image each group	3 images each group	5 images each group
Average filtering (3 × 3)	0.0061	0.0057	0.0058	0.0123	0.0118	0.0087
Average filtering (5 × 5)	0.0105	0.0102	0.0099	0.0317	0.0309	0.0232
Average filtering (9 × 9)	0.0234	0.0233	0.0217	0.0751	0.0735	0.0655
Gaussian filtering (3 × 3)	0.0058	0.0054	0.0055	0.0118	0.0114	0.0084
Gaussian filtering (5 × 5)	0.0094	0.0090	0.0088	0.0269	0.0264	0.0195
Gaussian filtering (9 × 9)	0.0143	0.0141	0.0133	0.0458	0.0448	0.0359
Median filtering (3 × 3)	0.0056	0.0049	0.0055	0.0068	0.0071	0.0098
Median filtering (5 × 5)	0.0187	0.0167	0.0194	0.0223	0.0238	0.0298
Median filtering (9 × 9)	0.0652	0.0551	0.0596	0.0731	0.0755	0.0961