Application of Fractional Wave Packet Transform for Robust Watermarking of Mammograms

Table 3

Correlation coefficients of extracted watermarks (mdb001).

β	β = 0.5		β = 1.5		β = 2.0		β = 2.5
Attack	PSNR	Correlation coefficient	PSNR	Correlation coefficient	PSNR	Correlation coefficient	PSNR	Correlation coefficient
No attack	57.6742	0.9586	48.7639	0.9951	46.4094	0.9946	44.5710	0.9970
Weiner	47.9247	0.2171	46.9645	0.6886	46.3327	0.7492	45.7129	0.7842
Median filtering	34.9318	0.0002	34.7781	0.0037	34.6527	0.0366	34.5133	0.05360
Salt and pepper noise	26.2601	0.0704	24.4059	0.1352	26.3242	0.1933	25.9943	0.2644
Cropping	3.8383	0.0932	3.8466	0.0956	3.8505	0.0972	3.8541	0.0981
Compression	43.7967	0.1001	43.0275	0.3107	42.5067	0.4475	42.0062	0.5454
Rotation	21.8911	−0.0137	21.8871	−0.0264	21.8810	−0.0165	21.8738	−0.0162
Resizing	49.458	0.5626	49.2708	0.9406	48.9864	0.9642	48.7016	0.9735
Sharpening	32.3031	0.2374	32.1365	0.6153	32.0112	0.7222	31.8713	0.7826
Gaussian filter	48.0211	0.4770	47.8309	0.9038	47.6739	0.9463	47.4890	0.9632