In this work, we explore the role of synthetic data in improving the detection of Hand-Object Interactions from egocentric images. Through extensive experimentation and comparative analysis on VISOR, EgoHOS, and ENIGMA-51 datasets, our findings demonstrate the potential of synthetic data to significantly improve HOI detection, particularly when real labeled data are scarce or unavailable. By using synthetic data and only 10% of the real labeled data, we achieve improvements in Overall AP over models trained exclusively on real data, with gains of +5.67% on VISOR, +8.24% on EgoHOS, and +11.69% on ENIGMA-51. Furthermore, we systematically study how aligning synthetic data to specific real-world benchmarks with respect to objects, grasps, and environments, showing that the effectiveness of synthetic data consistently improves with better synthetic-real alignment. As a result of this work, we release a new data generation pipeline and the new HOI-Synth benchmark, which augments existing datasets with synthetic images of hand-object interaction. These data are automatically annotated with hand-object contact states, bounding boxes, and pixel-wise segmentation masks. All data, code, and tools for synthetic data generation are available at: https://fpv-iplab.github.io/HOI-Synth/.
Figures & tables
Figure 1: We explore the role of synthetic data in egocentric hand-object interaction detection by generating and automatically labeling synthetic datasets (left). We then analyze domain adaptation scenarios where models are trained using both synthetic and real unlabeled data, with varying amounts of labeled real data (right).
Figure 2: The proposed data generation pipeline. (a) An object-grasp pair is selected from DexGraspNet Wang et al. (2023) and integrated with a randomly generated human model. (b) The human + object model is placed in an environment randomly selected from the Habitat-Matterport 3D dataset Ramakrishnan et al. (2021) . (c) Egocentric data of hand-object interactions is generated and automatically labeled. Labels include bounding boxes and segmentation masks of hands and interacted objects, contact-state, and hand-object relations.
Figure 3: Qualitative examples generated by our HOI-Synth Data Generation Pipeline . For each sample, the pipeline automatically generates rich ground-truth annotations, including 2D bounding boxes, pixel-wise segmentation masks, and interaction metadata describing the relationship between hands and manipulated objects.
Figure 4: A ENIGMA-51 image (left), a synthetic in-domain image (center), and a synthetic out-domain image (right).
Dataset
Images
Hands
Objects
HOI
VISOR Darkhalil et al. (2022)
32,857
52,906
42,785
42,787
Synthetic
30,259
60,098
45,219
45,353
Synthetic aligned Objects
4,951
9,810
8,311
8,263
Synthetic aligned Grasps
5,000
9,899
8,355
8,306
Synthetic aligned Environments
4,938
9,789
8,034
8,002
Synthetic aligned All
31,000
61,408
52,279
52,045
Table 1: Statistics of the training sets included in our HOI-Synth benchmark.
Figure 5: The architecture of the domain adaptation approach used in our analysis. The method is based on the Adaptive Teacher Li et al. (2022b) framework, extended with HOS recognition modules Darkhalil et al. (2022) .
% Real Labeled Data
Approach
Overall
H
H+S
H+C
O
0%
Synthetic-Only
09.88
28.41
24.89
08.64
01.23
UDA
33.33
80.16
65.98
33.47
8.35
Absolute Improvement
+23.45
+51.75
+41.09
+24.83
+7.12
Table 2: Results on the VISOR validation set considering different real data settings available in training. Gray rows indicate baseline models in each configuration, while white rows highlight models trained with synthetic and real data. In each group, the best results are in bold, while the best results among the models trained with synthetic and real data are underlined. Overall enhancements are shown in blue, indicating improvements of the models trained with synthetic and real data over the baseline .
Figure 6: Qualitative examples on VISOR . Columns show predictions from Real-Only , Synthetic+Real , and SSDA models. Colors denote the left hand (blue), right hand (red), and interacted objects (yellow). Yellow arrows highlight regions of interest where the SSDA model demonstrates superior performance compared to the other baselines.
Method
Overall
H
H+S
H+C
O
Synthetic + Real
38.19
89.98
84.67
55.88
18.49
MT Tarvainen and Valpola (2017)
43.69
88.78
84.40
60.94
21.89
MT+GRL Ganin and Lempitsky (2015)
43.97
88.64
84.27
58.21
21.82
UT Liu et al. (2021)
44.32
90.60
84.49
52.55
22.11
AT Li et al. (2022b)
45.55
90.37
84.42
52.59
22.15
Table 3: Results of different semi-supervised adaptation approaches trained with synthetic data and 25% VISOR labeled training data.
Figure 7: UDA Overall AP on VISOR validation set for different amounts of training synthetic data. The green indicator shows the best result.
Figure 8: The green row shows the selected synthetic objects aligned with those in VISOR (black row). The red row contains the discarded examples, filtered out due to misalignment or poor quality. Note that these objects are common kitchen items, such as mugs, containers, and bottles.
Approach
Objects
Grasps
Environments
#Images
Overall
H
H+C
O
Baseline
∼5k
31.52
79.58
30.19
7.35
Target Objects
✓
∼5k
32.60
82.87
34.32
7.56
Target Grasps
✓
∼5k
31.84
82.01
31.95
7.97
Target Environments
✓
∼5k
31.59
81.22
32.68
7.16
Target All
✓
✓
✓
∼5k
32.59
82.86
34.37
7.53
Baseline
∼30k
33.33
80.16
33.47
8.35
Table 4: Performance comparison of the UDA Approach with aligned features on the VISOR dataset.
Figure 9: The green row shows examples of selected grasps aligned with real grasps from VISOR (black row). The red row contains discarded cases due to misalignment or unrealistic grasp configurations.
Figure 10: Green rows contain some examples of selected synthetic images aligned with VISOR images (black row). Note that the selected environments mainly present kitchens. The red row shows discarded examples due to misalignment or unsuitable viewpoints.
% Real Labeled Data
Approach
Overall
H
H+S
H+C
O
0%
Synthetic-Only
07.16
18.25
15.93
05.33
01.24
UDA
28.16
70.30
59.21
20.84
09.65
Absolute Improvement
+21.00
+52.05
+43.28
+15.51
+8.41
Table 5: Results on the EgoHOS Zhang et al. (2022) test set.
Figure 11: Qualitative examples on EgoHOS .
% Real Labeled Data
Approach
In-domain
Overall
H
H+S
H+C
O
10% (347 images)
Real-Only
✓
45.39
81.25
76.22
37.96
39.53
SSDA
57.08
85.40
78.62
43.56
46.97
SSDA
✓
56.69
84.58
78.42
41.17
46.50
Absolute Improvement
+11.69
+4.15
+2.40
+5.60
+7.44
25% (870 images)
Real-Only
✓
51.83
82.95
78.70
43.52
45.25
SSDA
58.17
84.99
80.41
46.31
49.34
Table 6: Results on the ENIGMA-51 Ragusa et al. (2024) test set.
Figure 12: Qualitative examples on ENIGMA-51 .
Approach
Target FOV
In-domain
Overall
H
H+C
O
Synthetic-Only
00.21
01.07
00.03
00.99
Synthetic-Only
✓
05.67
15.78
02.66
02.31
Synthetic-Only
✓
✓
12.85
56.05
15.24
4.79
Table 7: Performance comparison when aligning the FOV of out-domain synthetic data to that of ENIGMA-51 .
Background
Overall
H
H+C
O
Baseline
31.52
79.58
30.19
7.35
ImageNet
28.86
77.38
27.16
5.47
VISOR
27.41
82.30
6.09
2.56
Table 8: Performance comparison on the VISOR validation dataset using the UDA model trained on 5k synthetic images with different backgrounds. The baseline with coherent backgrounds outperforms the models trained with ImageNet and VISOR backgrounds, highlighting the importance of background alignment for cross-domain performance.
Dataset
Approach
Contact F1
Side F1
VISOR
Real-Only
79.46
98.92
VISOR
FSDA
81.65
99.06
EgoHOS
Real-Only
78.78
98.33
EgoHOS
FSDA
79.25
98.87
ENIGMA-51
Real-Only
77.28
98.80
ENIGMA-51
FSDA
77.83
99.11
Table 9: Comparison of FSDA vs Real-Only for F1 Scores of Contact and Side.
Figure 13: Simple HOI generation approach: Object models and hands are randomly projected onto ImageNet backgrounds.
Generation approach
Overall
H
H+C
O
Contact F1
Synthetic augmentation
19.62
62.40
11.91
3.60
8.78
Simulation (Ours)
30.54
79.05
31.51
7.33
22.75
Table 10: UDA Results on VISOR : Comparison of simulation-based image generation and classic synthetic augmentations.