A QR Code Based Zero-Watermarking Scheme for Authentication of Medical Images in Teleradiology Cloud

Table 2

NC values under Matlab attacks.

Attack	Modality
	CT	Mammogram	MRA	Nuclear	PET	Ultrasound	X-ray
JPEG compression; Quality factor: 50%	0.9999	0.9854	0.9999	1.0000	0.9995	1.0000	0.9990
Average; Window size: [9×9]	0.9999	0.9891	0.9999	1.0000	0.9995	1.0000	0.9992
Median; Window size: [9×9]	0.9999	0.9885	0.9997	1.0000	0.9998	1.0000	0.9991
Blur; Window size: [9×9]	0.9999	0.9885	0.9997	1.0000	0.9997	1.0000	0.9993
Sharpening; +50% sharpness	0.9999	0.9875	0.9999	1.0000	0.9997	1.0000	0.9990
Gaussian; Noise: 30%	0.9999	0.9755	0.9997	1.0000	0.9994	1.0000	0.9984
Contrast; Sharpness: +50%	0.9999	0.9904	0.9998	1.0000	0.9995	1.0000	0.9985
Gamma correction; Gamma value: 0.6	0.9999	0.9841	0.9999	1.0000	0.9997	1.0000	0.9993
Histogram; Equalization	0.9999	0.9824	0.9998	1.0000	0.9995	1.0000	0.9986
Resizing; Scale factor: 0.5	0.9999	0.9804	0.9999	1.0000	0.9994	1.0000	0.9984
Rotation; Angle: 3°	0.9999	0.9850	0.9997	1.0000	0.9994	1.0000	0.9985
Distortion; Warp factor: 3	0.9999	0.9831	0.9997	1.0000	0.9994	1.0000	0.9988