Table 6 Quality assessment using the mean square error (MSE) and the signal-to-noise ratio (SNR) of the extracted watermark signal, when the watermarked Lena image is altered by various attacks.
From: Time-Frequency and Time-Scale-Based Fragile Watermarking Methods for Image Authentication
Attacks | Quality Assessment | |
|---|---|---|
| Â | MSE | SNR (dB) |
Histogram equalization | 0.1282 | 8.92 |
Sharpening | 0.1038 | 9.84 |
Blurring | 0.1062 | 9.74 |
Gaussian noise | 0.1202 | 9.20 |
Salt-and-pepper noise | 0.0926 | 10.34 |