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

Table 1

Performance measures for checkmark attacks.

Attack	Parameter	BER	NC	Extracted watermark
Cropping	Cropping %: 20	0.0001	0.9999
	Cropping %: 50	0.0002	0.9999
	Cropping %: 75	0.0003	0.9999
Dithering	No parameters	0.0001	0.9999
Denoising & remodulation	Window size: 3×3	0.0001	0.9999
	Window size: 5×5	0.0001	0.9999
Denoising & remodulation assuming a correlated watermark	Window size: 3×3	0.0002	0.9999
	Window size: 5×5	0.0001	0.9999
Gaussian	Window size: 3×3	0.0000	1.0000
	Window size: 5×5	0.0000	1.0000
Hard thresholding	Window size: 3×3	0.0002	1.0000
	Window size: 5×5	0.0002	1.0000
JPEG compression	Compression factor: 10	0.0210	1.0000
	Compression factor: 15	0.0046	0.9999
	Compression factor: 25	0.0007	0.9999
	Compression factor: 30	0.0021	1.0000
	Compression factor: 40	0.0011	0.9999
	Compression factor: 50	0.0010	0.9999
Linear	Transformation matrix; 1.15−0.02−0.030.9	0.0001	0.9999
	Transformation matrix; −0.85−0.2−0.051.3	0.0001	0.9999
Median	Window size: 3×3	0.0001	1.0000
	Window size: 4×4	0.0003	0.9999
Midpoint	Window size: 3×3	0.0001	1.0000
	Window size: 5×5	0.0002	0.9999
Line removal	Row: 12, Col: 9	0.0001	0.9999
	Row: 5, Col: 51	0.0001	0.9999
Projection	Angle: 5.00; Axis: 1.00; Distance factor: 2.00; Radius factor: 2.00	0.0001	0.9999
	Angle: 30.00; Axis: 1.00; Distance factor: 2.00; Radius factor: 2.00	0.0001	0.9999
Aspect ratio	𝑋 scale: 0.80; 𝑌 scale: 1.00	0.0001	0.9999
	𝑋 scale: 1.00; 𝑌 scale: 1.10	0.0001	0.9999
Rotation	Angle: 15	0.0001	0.9999
	Angle: 45	0.0001	0.9999
Rotation scale	Angle: −2	0.0012	0.9999
	Angle: 45	0.0001	0.9999
Row column removal	Row: 17, Col: 5	0.0002	0.9999
	Row: 5, Col: 1	0.0001	0.9999
Up- & downsampling	Downsampling factor: 0.50; Upsampling factor: 2.00	0.0002	0.9999
	Downsampling factor: 0.75; Upsampling factor: 1.30	0.0001	0.9999
Scale	Scale factor: 2	0.0001	0.9999
	Scale factor: 0.5	0.0001	0.9999
Sharpening	No parameters	0.0002	0.9999
Shearing	𝑥 Shear %: 0; 𝑦 Shear %: 5	0.0001	0.9999
	𝑥 Shear %: 5; 𝑦 Shear %: 5	0.0002	0.9999
Soft thresholding	Window size: 3×3	0.0002	1.0000
	Window size: 5×5	0.0002	1.0000
Stirmark	Random	0.0001	0.9999
Template removal	No parameters	0.0001	0.9999
Thresholding	No parameters	0.0008	0.9999
Trim median	Window size: 3×3	0.0001	1.0000
	Window size: 5×5	0.0003	0.9999
Warping	Warp factor: 3	0.0001	0.9999
	Warp factor: 6	0.0001	0.9999
	Warp factor: 12	0.0001	0.9999
	Compression factor: 10	0.0019	0.9999
	Compression factor: 20	0.0009	0.9999
Wavelet compression	Compression factor: 30	0.0004	0.9999
	Compression factor: 40	0.0006	0.9999
	Compression factor: 50	0.0005	0.9999
Weiner filtering	Window size: 3×3	0.0003	0.9999
	Window size: 5×5	0.0002	0.9999