[Retracted] Robust and Secure Zero-Watermarking Algorithm for Medical Images Based on Harris-SURF-DCT and Chaotic Map

Figure 12

Some attacked medical and extracted watermarks under geometric attacks: (a) Rotation clockwise 44°. (b) Rotation counterclockwise 46°. (c) Scaling 3.4. (d) Scaling 0.3. (e) Translation left 31%. (f) Translation up 31%. (g) X-axis cropping 30%. (h) Y-axis cropping 31%.

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