Research Article
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 |
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