Deep learning-based watermarking has made remarkable progress in recent years. To achieve robustness against various distortions, current methods commonly adopt a training strategy where a single random distortion (SRD) is chosen as the noise layer in each training batch. However, the SRD strategy treats distortions independently within each batch, neglecting the inherent relationships among different types of distortions and causing optimization conflicts across batches. As a result, the robustness and generalizability of the watermarking model are limited. To address this issue, we propose a novel training strategy that enhances robustness and generalization via meta-learning with feature consistency (Meta-FC). Specifically, we randomly sample multiple distortions from the noise pool to construct a meta-training task, while holding out one distortion as a simulated ``unknown'' distortion for the meta-testing phase. Through meta-learning, the model is encouraged to identify and utilize neurons that exhibit stable activations across different types of distortions, mitigating the optimization conflicts caused by the random sampling of diverse distortions in each batch. To further promote the transformation of stable activations into distortion-invariant representations, we introduce a feature consistency loss that constrains the decoded features of the same image subjected to different distortions to remain consistent. Extensive experiments demonstrate that, compared to the SRD training strategy, Meta-FC improves the robustness and generalization of various watermarking models by an average of 1.59%, 4.71%, and 2.38% under high-intensity, combined, and unknown distortions.
Figures & tables
Figure 1: The difference of the training process between SRD and Meta-FC. (a) The SRD pipeline. (b) The Meta-FC pipeline. In the meta-training phase, the model learns to be robust against known distortions. In the meta-testing phase, the model is evaluated under a simulated “unknown” distortion. Note that no truly unknown distortions are involved during the entire training process.
Figure 2: The whole training process of our proposed Meta-FC. First, the main encoder and decoder are used to process images under meta-training distortions, yielding the meta-training loss Lmeta-train (composed of Lw,n and Lmsgtra ) and producing temporary encoder and decoder parameters. Next, these temporary parameters are evaluated on the meta-testing distortions to calculate the meta-testing loss Lmeta-test (composed of Lmsgtes ). Subsequently, the image loss Limg (composed of Limgtra and Limgtes ) is computed based on the watermarked images generated by the main and the temporary encoders. Finally, the main model parameters are updated by minimizing the total loss Ltotal , which consists of Lmeta-train , Lmeta-test , and Limg .
Figure 3: Result of the visual quality of SRD and our method under different models. The first row presents the cover image, followed by the watermarked images in the second row. The third row shows the watermarked images subjected to various distortions. The fourth row illustrates the residuals, which represent the difference between the watermarked and cover images and are magnified by a factor of 5 to enhance visibility. The final two rows report the PSNR(dB) and SSIM values of each model, respectively, where consistent visual quality is maintained across training methods for the same model.
Datasets
Models
Strategy
Identity
GB ( σ=6 )
SPN ( σ=0.15 )
Crop ( p=0.7 )
JPEG ( Q=30 )
MB ( w=7 )
GN ( σ=0.08 )
Bright ( f=4 )
Dropout ( p=0.7 )
Avg.
DIV2K
StegaStamp
SRD
100
100
98.07
86.56
95.84
99.97
97.89
77.70
94.33
94.48
Meta-FC
100
100
99.07
90.00
97.42
99.99
98.25
80.84
94.56
95.57
MBRS
SRD
100
99.02
97.46
91.94
83.95
90.82
93.98
94.25
99.76
94.58
Meta-FC
100
99.33
98.44
95.78
86.79
95.25
96.01
93.93
99.75
96.14
FIN
SRD
99.97
96.25
97.27
81.16
99.04
90.15
93.89
88.73
83.29
92.19
Meta-FC
100
97.16
98.27
83.15
99.89
90.18
95.70
89.32
85.58
93.25
Table 1: Comparison of ACC (%) under high-intensity distortions. To ensure a fair comparison, the embedding strength of each baseline model is adjusted for both SRD and Meta-FC, such that the resulting PSNR values remain consistent across methods.
Datasets
Models
Strategy
MB&JPEG
MB&SPN
MB&GN
GN&SPN
GN&JPEG
MB&SPN &GN
MB&JPEG &Crop
Avg.
DIV2K
StegaStamp
SRD
99.13
99.81
98.54
97.49
97.04
94.78
97.21
97.71
Meta-FC
99.78
99.81
99.01
98.50
98.26
95.52
97.89
98.40
MBRS
SRD
71.47
90.24
72.09
94.11
75.98
65.98
69.81
77.10
Meta-FC
81.53
98.88
82.70
96.31
80.21
74.92
79.31
84.84
FIN
SRD
95.98
91.23
80.13
93.38
93.25
75.59
92.56
88.87
Meta-FC
97.01
92.32
80.06
95.70
95.54
76.69
95.38
90.38
Table 2: Comparison of ACC (%) under combined distortions. PSNR is kept consistent across training methods for each baseline, following the same setup as in the high-intensity distortion evaluation.
Datasets
Model
Strategy
JPEG ( Q=50 )
Bright ( f=3 )
Dropout ( p=0.7 )
Erasing ( σ=0.6 )
Contrast ( f=4 )
Saturation ( f=3 )
Cropout ( p=0.7 )
Crop ( p=0.7 )
Avg.
DIV2K
StegaStamp
SRD
99.89
77.53
82.75
78.63
77.05
61.60
81.17
84.11
80.34
Meta-FC
99.97
78.43
84.34
79.22
79.28
68.80
86.39
85.68
82.76
MBRS
SRD
60.30
92.70
99.02
82.45
96.13
99.71
91.25
89.53
88.89
Meta-FC
73.65
92.66
99.74
85.35
96.41
99.98
91.54
91.18
91.31
FIN
SRD
99.93
90.09
81.93
73.45
89.23
99.38
77.51
78.44
86.25
Meta-FC
99.98
90.74
83.41
76.06
89.45
99.46
79.17
79.57
87.23
Table 3: Comparison of ACC (%) under unknown distortions.
Strategy
ACC(%) ↑
High-intensity
Combined
Unknown
Mate-FC w/o meta-train & FC
94.34 ( ↓ 1.59)
87.94 ( ↓ 4.71)
88.55 ( ↓ 2.38)
Mate-FC w/o meta-test & FC
95.27 ( ↓ 0.66)
90.58 ( ↓ 2.07)
88.96 ( ↓ 1.97)
Mate-FC w/o FC
95.56 ( ↓ 0.37)
90.44 ( ↓ 2.21)
90.99 ( ↑ 0.06)
Meta-FC
95.93
92.65
90.93
Table 4: Ablation study on different parts in our proposed Meta-FC architecture.
Strategy
StegaStamp
MBRS
FIN
SepMark
DERO
Time (h)
ACC (%)
Time (h)
ACC (%)
Time (h)
ACC (%)
Time (h)
ACC (%)
Time (h)
ACC (%)
SRD
1.81
94.67
2.07
85.93
1.68
90.80
1.99
89.19
1.77
95.05
Meta-FC
2.36
96.87
3.37
90.40
2.86
92.35
3.12
95.48
2.53
96.59
Table 5: Comparison of training time for SRD and Meta-FC.