Table 4 The attacked images, the corresponding PSNR values, the retrieved watermark images, and the corresponding RR values
| Â | Image blurring | Surround cropping | Quarter cropping | Nosing |
|---|---|---|---|---|
Attacked image |
|
|
|
|
PSNR(dB) | 38.71 | 11.24 | 11.77 | 11.38 |
Retrieved watermark |
|
|
|
|
RR | 98.27% | 96.48% | 97.17% | 95% |
| Â | JPEG | Scaling | Sharpening | Median filtering |
Attacked Image |
|
|
|
|
PSNR (dB) | 30.37 | 25.36 | 18.45 | 26.15 |
Retrieved watermark |
|
|
|
|
RR | 98.29% | 98.22% | 98.29% | 97.46% |
| Â | Average filtering | Gamma correction | Histogram equalization | Pixel shifting |
Attacked Image |
|
|
|
|
PSNR (dB) | 24.43 | 12.80 | 11.53 | 2.69 |
Retrieved watermark |
|
|
|
|
RR | 97.02% | 97.9% | 96.78% | 89.6% |
