Weakly-supervised video scene graph generation (WS-VSGG) aims to parse video content into structured relational triplets without bounding box annotations and with only sparse temporal labeling, significantly reducing annotation costs. Without ground-truth bounding boxes, these methods rely on off-the-shelf detectors to generate object proposals, yet largely overlook a fundamental discrepancy from fullysupervised pipelines. Fully-supervised detectors implicitly filter out noninteractive objects, while off-the-shelf detectors indiscriminately detect all visible objects, overwhelming relation models with noisy pairs.We address this by introducing a learnable pair affinity that estimates the likelihood of interaction between subject-object pairs. Through Pair Affinity Learning and Scoring (PALS), pair affinity is incorporated into inferencetime ranking and further integrated into contextual reasoning through Pair Affinity Modulation (PAM), enabling the model to suppress noninteractive pairs and focus on relationally meaningful ones. To provide cleaner supervision for pair affinity learning, we further propose Relation- Aware Matching (RAM), which leverages vision-language grounding to resolve class-level ambiguity in pseudo-label generation. Extensive experiments on Action Genome demonstrate that our approach consistently yields substantial improvements across different baselines and backbones, achieving state-of-the-art WS-VSGG performance.
Figures & tables
Figure 1: Detection distribution and matching in FS-VSGG and WS-VSGG. (a) Per-frame detection statistics in the weakly annotated training set. Detections are categorized as True Match (spatial overlap with a ground-truth), False Match (class-matched without overlap), or Unmatched. (b) Detection and matching comparison for the triplet ⟨ person, holding, cup/glass/bottle ⟩ . Fully-supervised detector produces relation-relevant proposals, whereas off-the-shelf detector generates many irrelevant objects, leading to false matches (e.g., cup 2) under class-level matching. Our method retains only the interaction-consistent instance (cup 1).
Figure 2: Comparison of WS-VSGG training pipelines. Gu : annotation of unlocalized triplets, Dt : detected object proposals. (a) Only matched pairs P+ are used for training; unmatched pairs P− are discarded. (b) RAM refines the matching, and both P+ and P− are used to learn predicate classification and pair affinity jointly.
Figure 3: Overview of Relation-Aware Matching (RAM). For each entity in a triplet, a relation-aware query is constructed and fed into a VL grounding model. The [CLS] cross-attention map localizes the described relation, and reliability estimation determines whether to perform grounded matching via Grounding Score (GS) or fall back to class-level matching. The figure illustrates the process for co ; the same procedure is applied independently to cs .
Figure 4: Overview of PALS and PAM. (a) The relation embedding R0 and pair affinity embedding P0 are jointly updated through L spatial and temporal attention blocks, then decoded into predicate classification scores PC and pair affinity scores PA for inference. (b) Inside each attention block, the affinity matrix Gi=PiPi⊤ gates the attention logits, and the attention output updates both R and P via residual connections. The figure illustrates spatial attention for clarity; temporal attention follows the same mechanism with backbone-specific sequence grouping across frames.
Backbone
Supervision
Method
With Constraint
No Constraint
R@10
R@20
R@50
R@10
R@20
R@50
RLIPv2 [ 34 ]
Zero-shot
Vanilla
5.06
8.37
10.05
5.98
14.60
21.42
STTran [ 2 ]
Full
Vanilla
25.20
34.10
37.00
24.60
36.20
48.80
Weak
PLA [ 1 ]
15.39
21.44
26.24
15.83
22.83
31.74
PLA + Ours
22.24
26.48
28.00
23.20
30.24
37.47
TRKT [ 33 ]
17.56
22.33
27.45
18.76
24.49
33.92
Table 1: Comparison with state-of-the-art methods on the AG dataset (SGDet). Methods are grouped by backbone and supervision level: Zero-shot denotes methods without any task-specific training, and Weak denotes training with unlocalized scene graph annotations. † indicates results reproduced with official code under identical settings. Best and second-best results among weakly-supervised methods within each backbone are in bold and underlined , respectively.
RAM
PALS
PAM
With Constraint
No Constraint
R@10
R@20
R@50
R@10
R@20
R@50
(a)
15.39
21.44
26.24
15.83
22.83
31.74
(b)
✓
19.79
24.00
26.34
21.03
26.94
33.63
(c)
✓
✓
20.22
24.48
26.83
21.63
27.84
34.73
(d)
✓
15.90
21.87
26.63
16.46
23.33
32.36
(e)
✓
✓
22.14
25.74
27.07
23.12
29.94
36.35
Table 2: Ablation study on the AG dataset (SGDet). Best results are in bold and second best are underlined .
Detection
VL Model
Match
TP
Precision
Recall
F1
PLA
–
16,137
6,480
0.4016
0.4423
0.4209
GLIP
9,109
5,363
0.5888 (+46.6%)
0.3660 ( − 17.2%)
0.4514 (+7.2%)
GDINO
8,067
5,853
0.7255 (+80.6%)
0.3995 ( − 9.7%)
0.5153 (+22.4%)
TRKT
–
21,976
7,012
0.3191
0.4786
0.3829
GLIP
11,945
5,472
0.4581 (+43.6%)
0.3735 ( − 22%)
0.4115 (+7.5%)
GDINO
10,444
5,846
0.5597 (+75%)
0.3990 ( − 17%)
0.4659 (+22%)
Table 3: Effect of RAM on pseudo-label quality. “–” denotes the original matching without RAM. Relative changes are shown in parentheses.
Figure 8
Figure 6: Qualitative comparison of top-10 predictions on the AG test set. Two video clips are shown, each with two consecutive frames. For each frame, input detections are overlaid, where ground-truth matched detections are shown in blue and unmatched detections in pink. In the prediction lists, predicates are ranked from [1] (highest score) to [10], and correctly predicted predicates are highlighted in yellow. Compared to the baseline (PLA), our method ranks more interaction-relevant object pairs within the top-10, while the baseline frequently assigns high ranks to non-interactive objects (e.g., floor, clothes, closet, door).
Appendix figures & tables14 assets
Supplementary material from the paper’s appendix.
Appendix
Hyperparameter
Value
Learning rate
1e-5
Epochs
5
Batch size
1 (video-level)
dR
1936
dP
128
λPA
1.0
Appendix
Table 5: Hyperparameter settings.
Model
Params (M)
FLOPs (G)
Latency (ms/video)
STTran
103.67
138.91
20.95
STTran + Ours
104.99 (+1.27%)
138.92 (+0.01%)
20.95 (+0%)
DSG-DETR
103.67
140.05
18.09
DSG-DETR + Ours
104.99 (+1.27%)
140.10 (+0.04%)
18.10 (+0.05%)
Appendix
Table 6: Computational overhead of PALS and PAM. FLOPs are measured with T=30 , N=18 . Latency is measured under the same setting and averaged over 100 runs on a single NVIDIA RTX 3090 GPU.
Backbone
Method
With Constraint
No Constraint
R@10
R@20
R@50
R@10
R@20
R@50
STTran
NL-VSGG
9.48
15.61
19.60
9.48
15.92
22.56
NL-VSGG + Ours
13.42
19.77
20.51
13.44
20.60
26.31
DSG-DETR
NL-VSGG
9.51
15.75
20.40
9.53
16.11
23.21
NL-VSGG + Ours
13.45
19.63
20.98
13.51
20.31
26.82
Appendix
Table 7: Performance of our method applied on top of NL-VSGG on the AG dataset (SGDet).
Figure 7: Sensitivity of R@10 to RAM thresholds on AG (SGDet). WC and NC denote With Constraint and No Constraint, respectively.
τr
Pseudo-label
With Constraint
No Constraint
Precision
Recall
F1
R@10
R@20
R@50
R@10
R@20
R@50
0.0
0.694
0.372
0.485
21.81
25.55
26.74
23.09
30.00
35.92
0.1
0.718
0.389
0.504
21.91
25.48
26.93
23.84
30.39
36.13
0.2
0.726
0.399
0.515
21.84
25.63
27.11
23.64
30.30
37.14
0.3
0.726
0.400
0.515
22.24
26.48
28.00
23.20
30.24
37.47
0.4
0.701
0.402
0.511
22.00
25.82
27.47
23.45
29.72
36.15
Appendix
Table 8: Sensitivity to τr ( τgs=0.2 fixed). The shaded row indicates the default setting.
τgs
Pseudo-label
With Constraint
No Constraint
Precision
Recall
F1
R@10
R@20
R@50
R@10
R@20
R@50
0.0
0.667
0.410
0.507
21.98
26.18
27.75
22.93
29.89
37.22
0.1
0.711
0.401
0.513
21.61
25.32
26.88
23.53
30.25
37.05
0.2
0.726
0.400
0.515
22.24
26.48
28.00
23.20
30.24
37.47
0.3
0.736
0.392
0.512
22.00
25.79
27.36
23.77
30.29
36.48
0.4
0.747
0.383
0.506
21.99
25.61
27.12
23.71
30.10
36.51
Appendix
Table 9: Sensitivity to τgs ( τr=0.3 fixed). The shaded row indicates the default setting.
Figure 8: Attention map comparison across five vision-language models on three multi-instance scenarios. Each row shows the same input frame with a language query (shown in brackets) that requires relational understanding to identify the correct target among multiple instances of the same category. Yellow boxes indicate ground-truth regions. GroundingDINO, GLIP, and MDETR produce activations consistently concentrated on the query-relevant region, whereas SigLIP2 and BLIP fail to localize the target, exhibiting diffuse or query-agnostic activation patterns.
Model
Pseudo-label
With Constraint
No Constraint
Prec.
Rec.
F1
R@10
R@20
R@50
R@10
R@20
R@50
GLIP
0.589
0.366
0.451
21.21
25.10
26.65
22.86
29.66
36.80
MDETR
0.730
0.369
0.490
22.11
25.66
27.10
22.96
30.18
37.20
GroundingDINO
0.726
0.400
0.515
22.24
26.48
28.00
23.20
30.24
37.47
Appendix
Table 10: Performance comparison of compatible VL models under the same hyperparameter setting ( τr=0.3 , τgs=0.2 ). Bold indicates the best result.
Figure 9: Failure cases of RAM across GroundingDINO, GLIP, and MDETR. Yellow boxes indicate ground-truth regions. Top: categorical ambiguity of the relation-satisfying object. Bottom: heavy occlusion of the relation-satisfying object.
Figure 10: PA score distributions under standard BCE (left) and class-balanced BCE (right). Standard BCE collapses both distributions toward zero due to class imbalance, whereas class-balanced BCE produces well-separated positive and negative distributions.
Loss
With Constraint
No Constraint
R@10
R@20
R@50
R@10
R@20
R@50
BCE
21.94
25.60
27.10
22.16
30.17
36.84
Balanced BCE (default)
22.24
26.48
28.00
23.20
30.24
37.47
Appendix
Table 11: Effect of loss formulation on pair affinity learning.
Subset
Method
With Constraint
No Constraint
R@10
R@20
R@50
R@10
R@20
R@50
High NI
w/o PAM
6.04
7.90
8.88
5.86
8.31
11.55
w/ PAM
10.32 (+4.28)
12.14 (+4.24)
13.97 (+5.09)
10.56 (+4.70)
13.21 (+4.90)
15.79 (+4.24)
Low NI
w/o PAM
33.50
39.12
40.42
35.00
45.17
54.30
w/ PAM
33.88 (+0.38)
39.89 (+0.77)
41.30 (+0.88)
35.27 (+0.27)
46.11 (+0.94)
55.84 (+1.54)
Appendix
Table 12: Performance on video subsets grouped by non-interactive pair ratio. High NI and Low NI denote the top and bottom 25% of test videos ranked by per-video non-interactive pair ratio, respectively. The w/o PAM model corresponds to row (e) of Table 2 in the main paper (RAM + PALS, without PAM). Red values in parentheses denote the gain of w/ PAM over w/o PAM. Bold denotes the better result within each subset.
Margin
With Constraint
No Constraint
R@10
R@20
R@50
R@10
R@20
R@50
Soft margin
21.79
25.63
27.33
23.69
29.94
36.31
m=0.5
21.92
25.77
27.40
23.67
30.15
36.59
m=1.0 (default)
22.24
26.48
28.00
23.20
30.24
37.47
m=2.0
22.01
25.84
27.36
23.73
30.39
36.95
Appendix
Table 13: Sensitivity to PAM margin setting. The shaded row indicates the default setting. Bold and underline denote the best and second-best results in each column, respectively.
Figure 11: Additional qualitative comparisons between the baseline and ours.