Research Article
Multipurpose Watermarking Algorithm for Medical Images
Table 2
Similarity of watermark extracted under various attacks.
| Attack types | Similarity of robust watermark (NC) | Skull | Mediastinum | Liver | This paper | [14] | [27] | [26] | [28] | This paper | [14] | [27] | [26] | [28] | This paper | [14] | [27] | [26] | [28] |
| No attack | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | Gaussian filter (3 3 = 0.3) | 0.956 | — | 0.979 | — | 0.971 | 0.954 | — | 0.977 | — | 0.967 | 0.944 | — | 0.972 | — | 0.959 | Median filter [3, 3] | 0.942 | 0.956 | 0.987 | 0.861 | 0.983 | 0.938 | 0.951 | 0.985 | 0.856 | 0.982 | 0.926 | 0.944 | 0.982 | 0.847 | 0.98 | White noise (0.01) | 0.961 | — | — | 0.970 | 0.958 | 0.959 | — | — | 0.969 | 0.956 | 0.951 | — | — | 0.963 | 0.949 | Salt and pepper noise (0.02) | 0.957 | 0.940 | 0.949 | 0.946 | 0.942 | 0.961 | 0.942 | 0.947 | 0.944 | 0.940 | 0.952 | 0.935 | 0.942 | 0.938 | 0.937 | Shear (1/16) | 0.921 | 0.852 | — | 0.935 | 0.941 | 0.920 | 0.863 | — | 0.931 | 0.933 | 0.906 | 0.842 | — | 0.920 | 0.922 | JPEG compression Q = 20 | 0.914 | — | — | — | 0.743 | 0.934 | — | — | — | 0.755 | 0.921 | — | — | — | 0.728 | JPEG compression Q = 50 | 0.955 | — | 0.872 | 0.822 | 0.857 | 0.952 | — | 0.883 | 0.820 | 0.870 | 0.943 | — | 0.865 | 0.809 | 0.854 | Shrink 30% | 0.982 | 0.977 | — | 0.861 | 1 | 0.985 | 0.978 | — | 0.858 | 1 | 0.976 | 0.971 | — | 0.857 | 1 | Enlarge 30% | 0.985 | 0.971 | — | 0.853 | 1 | 0.988 | 0.973 | — | 0.855 | 1 | 0.981 | 0.968 | — | 0.849 | 1 | Rotate 30°C | 0.983 | — | — | 0.892 | 0.975 | 0.978 | — | — | 0.888 | 0.974 | 0.972 | — | — | 0.883 | 0.972 | Rotate 45°C | 0.976 | 0.967 | — | — | 0.964 | 0.972 | 0.965 | — | — | 0.963 | 0.970 | 0.961 | — | — | 0.959 |
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