Cross-modal super-resolution (SR) on real-world misaligned data is challenging, as only unlabeled low-resolution (LR) source and high-resolution (HR) guide images with complex spatial misalignment are available. Previous methods either rely on simulated training data or adopt suboptimal alignment strategies that overlook cross-modal dependencies, limiting their practical performance. To address these issues, we propose RobSelf, a self-supervised model that jointly optimizes a misalignment-aware feature translator and a content-aware reference filter online. The translator resolves unsupervised cross-modal and cross-resolution alignment via weakly-supervised, misalignment-aware translation, yielding an aligned guide feature. Guided by this feature, the filter performs reference-based discriminative self-enhancement on the source, enabling SR prediction with high resolution and high fidelity. Experiments on synthesized data and collected real-world data demonstrate that RobSelf achieves state-of-the-art performance, outperforming existing self-supervised and supervised methods. Moreover, it achieves superior efficiency, being up to 15.3× faster than prior self-supervised methods.
Figures & tables
Figure 1: Real-world misaligned RGB-guided depth SR ( ×4 ). Our model achieves state-of-the-art performance, requiring no training data, ground-truth supervision, or pre-alignment. (a) LR source; (b) HR guide; (c) pre-aligned guide by MINIMA [ 36 ] ; (d) SSGNet [ 40 ] + pre-alignment; (e) SGNet [ 49 ] + pre-alignment; (f) RobSelf-Re (Ours).
Figure 2: RobSelf is solely supervised by the LR source. Within this framework, the translator is optimized under weak supervision to map Fguide into IpredTrans that mimics the source, while yielding FguideAligned . Guided by FguideAligned , the filter performs reference-based discriminative self-enhancement on Fsource to obtain FsourceEnhanced , from which IpredSR is generated. RobSelf has t wo variants depending on the the translator design.
Figure 3: Misalignment-aware feature translator. Each encoder layer downsamples by ×2 ; each decoder layer upsamples by ×2 .
Figure 4: Content-aware reference filter.
Figure 5: Examples from our collected real-world misaligned data. LR sources are overlaid on HR guides for better visualization of misalignments.
P2P [ 30 ]
CMSR [ 38 ]
DCTNet [ 69 ]
MMSR [ 12 ]
SSGNet [ 40 ]
SGNet [ 49 ]
C2PD [ 19 ]
DORNet [ 47 ]
RobSelf-Re
RobSelf-De
Self-Supervised
✓
✓
✗
✓
✓
✗
✗
✗
✓
✓
Pre-Alignment
✓
✗
✓
✓
✓
✓
✓
✓
✗
✗
Params (M)
0.2
1.18
0.48
0.25
0.31
36.39
65.06
3.05
0.76/0.87 ∗
0.81/0.92 ∗
×4 (RMSE ↓ )
2.81/2.33
1.91
2.19/2.16
2.22/1.88
2.20/1.92
2.44/2.33
2.12/2.06
2.57/2.46
1 .52
1.43
×8 (RMSE ↓ )
3.33/2.91
3.03
3.34/3.33
2.99/2.79
2.99/2.83
3.48/3.34
3.27/3.15
3.58/3.54
2 .57
2.49
Table 1: Synthesized misaligned RGB-guided depth SR. For methods lacking alignment strategies, results without and with pre-alignment are reported (wo/w). ∗ Params vary with SR factors ( ×4 / ×8 ) due to level i . The best and s econd best are highlighted.
Figure 6: Synthesized misaligned RGB-guided depth SR ( ×8 ). Image patches are shown due to space limit. *Pre-alignment applied.
P2P [ 30 ]
CMSR [ 38 ]
DCTNet [ 69 ]
MMSR [ 12 ]
SSGNet [ 40 ]
SGNet [ 49 ]
DCNAS [ 72 ]
DORNet [ 47 ]
RobSelf-Re
RobSelf-De
Self-Supervised
✓
✓
✗
✓
✓
✗
✗
✗
✓
✓
Pre-Alignment
✓
✗
✓
✓
✓
✓
✓
✓
✗
✗
Params (M)
0.2
1.18
0.48
0.25
0.31
9.22
0.60
3.05
0.65/0.76 ∗
0.70/0.81 ∗
×2 (RMSE ↓ )
3.75/3.51
2.53
3.27/3.14
2.93/2.76
2.93/2.74
3.18/2.98
3.49/3.27
3.24/3.04
2 .23
2.18
×4 (DSS ↑ )
1.7/2.2
6.7
4.1/4.5
5.0/5.6
5.0/5.5
4.7/5.1
3.6/4.1
4.3/4.9
8 .4
8.6
Table 2: Real-World misaligned RGB-guided depth SR. For methods lacking alignment strategies, results without and with pre-alignment are reported (wo/w). ∗ Params vary with SR factors ( ×2 / ×4 ) due to level i . The best and s econd best are highlighted.
Figure 7: Real-World misaligned RGB-guided depth SR (upper: ×2 ; lower: ×4 ). Image patches are shown due to space limit. *Pre-alignment applied.
P2P [ 30 ]
CMSR [ 38 ]
MMSR [ 12 ]
SSGNet [ 40 ]
Fusion-ArF [ 35 ]
Fusion-CAP [ 26 ]
PAN [ 8 ]
HSI SR [ 63 ]
RobSelf-Re
RobSelf-De
Self-Supervised
✓
✓
✓
✓
✗
✗
✗
✗
✓
✓
Pre-Alignment
✓
✗
✓
✓
✗
✗
✗
✗
✗
✗
Params (M)
0.2
1.18
0.25
0.31
47.39
0.38
7.17
10.97
0.91/1.02 ∗
0.96/1.07 ∗
×2 (RMSE ↓ )
18.72/18.91
3.42
8.94/8.91
8.96/9.04
6.58
4.40
5.19
4.52
3.09
3 .12
×4 (NIQE ↓ )
6.32/ 5.32
8.05
10.95/10.50
10.30/10.23
9.54
8.95
9.24
9.01
7.63
7 .60
Table 3: Real-World misaligned RGB-guided NIR SR. For methods lacking alignment strategies, results without and with pre-alignment are reported (wo/w). ∗ Params vary with SR factors ( ×2 / ×4 ) due to level i . The best and s econd best are highlighted.
Figure 8: Real-world misaligned RGB-guided NIR SR ( ×2 ). Image patches are shown due to space limit. *Pre-alignment applied.
Figure 9: Effectiveness of our translator and filter.
Translator
✗
✓
✗
✓
Filter
✗
✗
✓
✓
RMSE ↓
2.55
2.37
2.31
2.18
Table 4: Effect of our translator and filter. For first two settings, {Fsource,Fguide} or {Fsource,FguideAligned} are fused using a 1×1 conv. No feature fusion in last two settings.
Figure 10: Guide alignment performance: our translator vs. modules in [ 52 ] . Visualizations for real-world misaligned RGB-guided depth (left) and NIR (right) SR.
Figure 11: Our translator can “synthesize” missing guide structures. See the right part of the square pot. Visualizations by RobSelf-De for real-world NIR SR ( ×2 ).
Figure 12: Performance on well-aligned data: synthesized RGB-guided depth SR ( ×4 ).