Content moderation systems classify images as safe or unsafe but lack spatial grounding and interpretability: they cannot explain what sensitive behavior was detected, who is involved, or where it occurs. We introduce the Sensitive Benchmark (SenBen), the first large-scale scene graph benchmark for sensitive content, comprising 13,999 frames from 157 movies annotated with Visual Genome-style scene graphs (25 object classes, 28 attributes including affective states such as pain, fear, aggression, and distress, 14 predicates) and 16 sensitivity tags across 5 categories. We distill a frontier VLM into a compact 241M student model using a multi-task recipe that addresses vocabulary imbalance in autoregressive scene graph generation through suffix-based object identity, Vocabulary-Aware Recall (VAR) Loss, and a decoupled Query2Label tag head with asymmetric loss, yielding a +6.4 percentage point improvement in SenBen Recall over standard cross-entropy training. On grounded scene graph metrics, our student model outperforms all evaluated VLMs except Gemini models and all commercial safety APIs, while achieving the highest object detection and captioning scores across all models, at 7.6× faster inference and 16× less GPU memory.
Figures & tables
Split
Frames
Movies
Sens.
Gen.
Obj/fr
Attr/fr
Pred/fr
Train
9,999
95
4,999
5,000
3.42
8.09
2.50
Val
2,000
31
1,000
1,000
3.39
7.95
2.50
Test
2,000
31
989
1,011
3.41
8.04
2.52
Total
13,999
157
6,988
7,011
3.41
8.06
2.51
Table 1: Dataset split statistics of SenBen. Annotation density is averaged per frame.
Category
Tag
Train
Val
Test
Total
Immodesty
immodesty
734
177
155
1,066
nudity
370
62
88
520
nudity art
143
25
31
199
nudity implied
371
61
68
500
Sexual
sex. suggestive
579
104
111
794
kissing
248
47
49
344
Table 2: Per-tag frame counts across splits. Frames may carry multiple tags (avg 1.3 per sensitive frame).
Figure 2: Multi-task training architecture. DaViT vision features feed both a decoupled Q2L tag head (detached from the decoder) trained with Asymmetric Loss, and a fully fine-tuned encoder-decoder for four scene graph tasks. Suffix-based object identity ( :N ) replaces bounding box tokens in attribute and predicate outputs. VAR loss (Eq. 3 ) penalizes low recall on sensitive vocabulary tokens across decoder tasks.
Aspect
Recall Loss
Skeleton Recall
VAR (Ours)
Domain
Segmentation
Segmentation
Autoregressive
Unit
Per-class pixels
Thin structures
Vocab tokens
Formulation
Multiplicative
Additive
Additive
Table 3: VAR Loss in context of recall-focused losses.
System
RSB
F1SB
F1tag
CE (baseline)
.349
.389
.544
+Suffix
.366
.406
.509
+VAR
.376
.408
.509
+MinPermCE
.386
.415
.532
+Label smooth.
.385
.419
.533
+Sched. samp.
.392
.422
.516
Table 4: System ablation study. RSB : SenBen Recall, F1SB : SenBen F1, F1tag : macro tag F1 ( RSB / F1SB category-macro-averaged).
Removed
immod
sexual
viol
subst
other
avg
− Suffix
−4.6
−4.5
−6.5
−2.9
−0.4
−3.8
− VAR
−5.7
−7.7
−2.0
−0.9
−0.9
−3.4
− LS
−3.3
−5.7
+0.3
+0.4
+0.8
−1.5
− SS
−1.6
−2.8
+0.3
+0.8
−0.4
−0.7
− MinP
+0.5
−2.4
−1.4
+1.7
−0.4
−0.4
Table 5: Per-category RSB change when removing each ingredient from the full decoder (VAR+SS+MinP+LS+Suffix). Values are ΔRSB in percentage points.
Model
Params
F1tag
Robj
RSB
F1SB
cap
Gemini 3 Pro (low reas.)
—
.806
.295
.652
.647
.642
Gemini 3 Flash (low reas.)
—
.784
.271
.593
.583
.654
Q2L-bal (ours)
241M
.594
.420
.413
.428
.771
Q2L-agg (ours)
241M
.457
.409
.449
.431
.772
Claude Opus 4.6
—
.658
.082
.327
.404
.598
GLM-4.6V (reas.)
10.3B
.492
.123
.291
.364
.563
Table 6: SenBen results on 2,000 test frames. RSB / F1SB : SenBen Recall/F1, F1tag : tag F1, Robj : obj. recall, cap: caption sim.
Model
Params
Tags
F1tag
F1s
Q2L-bal (ours)
241M
16/16
.594
.847
Q2L-agg (ours)
241M
16/16
.457
.835
Azure Content Safety
—
5/16
.430
.504
OpenAI Moderation
—
6/16
.411
.664
LlavaGuard 1.2
7.0B
6/16
.384
.583
Google SafeSearch
—
8/16
.341
.476
Table 7: Tag detection comparison. Tags:covered MECD tags. F1tag : macro tag F1 over supported tags. F1s : safe/unsafe F1.
Figure 3: Qualitative SenBen annotations from our custom annotation web app. Each frame shows bounding boxes, predicate arrows, and the object panel with attributes. The scene graphs capture diverse sensitive content: single-object violence (a), multi-actor violence (b), and substance use (c), all using the canonical SenBen vocabulary.
Model
Params
ms/fr
VRAM
$/2K
F1SB
Q2L-bal (ours)
241M
733
1.2 GB
0
.428
Claude Sonnet 4.6
—
3438
—
12.14
.339
Claude Opus 4.6
—
4555
—
20.02
.404
Gemini 3 Pro † (low reas.)
—
5579
—
26.58
.647
Qwen3-VL-8B
8.3B
5,614
18.8 GB
0
.340
Gemini 3 Flash (low reas.)
—
6121
—
5.80
.583
Table 8: Inference efficiency. Latency:sequential 5-frame avg. VRAM:peak GPU memory. $/2K:total API cost for 2000 frames.