Organizations: Visual Intelligence for Transportation (VITA) Laboratory, EPFL, Switzerland · Faculty of Computer Science, University of Vienna, Vienna, Austria
Estimating the metric 3D position of people from a monocular camera is important for robot navigation and motion prediction. Lightweight pose-based localizers are attractive for robotic hardware with limited computational resources because they operate on compact 2D keypoints. However, they typically discard the richer visual representations computed by the pose estimator. We introduce MoSoLoco, a per-frame monocular 3D human localizer that combines the pose detector's internal visual features with the detected 2D skeleton, without requiring an additional RGB or depth encoder. MoSoLoco can further incorporate sparse same-frame multi-person context to refine individual position estimates. Experiments on JRDB and NuScenes show that reusing pose-detector representations improves localization, reducing the best JRDB error by approximately 23 percent relative to the strongest evaluated keypoint-based baseline. A sparse social-interaction module incorporates nearby detections from the same image for further refinement. Controlled trajectory-forecasting experiments show downstream benefits, while the complete pipeline remains suitable for efficient Jetson AGX Xavier inference.
Figures & tables
Fig. 2: Overview of MoSoLoco architecture. (Left) Given RGB images and camera intrinsic parameters, the framework produces per-frame 3D world coordinates using three key localization components: (1) DETRPose [ janampa2025detrpose ] for multi-person 2D pose detection, (2) a non-linear probe that maps each joint-specific decoder embedding to a latent feature, and (3) the MoSoLoco network. Fixed trajectory forecasters use the estimated coordinates for downstream evaluation. (Right) MoSoLoco processes explicit 2D skeletons and the joint-aligned latent features via dual streams. Both streams are linearly projected and processed independently before bidirectional cross-attention exchanges geometric and latent information. Attentive pooling produces one token per person hypothesis. An optional sparse k -nearest-neighbor attention block then incorporates within-frame context before the regression head recovers the center of the pedestrian’s 3D bounding box.
Dataset
Matched
PC (EV)
Pearson r
Spearman ρ
Partial r
JRDB
2,964
3 (11.2%)
0.652
0.643
0.168
NuScenes
2,252
1 (15.0%)
0.846
0.852
0.369
TABLE I: Frozen DETRPose feature association with camera-axis depth. PC is the strongest absolute Pearson-correlated component among the first 32; EV is explained variance. Partial r controls the coarse cues described in text.
TABLE II: JRDB localization. Params/Size report localizer parameters and FP32 storage; Peak/GFLOPs follow the resource protocol. Detector headers give shared front-end cost. Bold denotes best ADE.
Fig. 3: Qualitative social refinement. The anchor is shown with attended neighbors; color denotes relative attention weight. (a) A compact, strongly articulated anchor overlaps a bicycle while neighbors are upright pedestrians, and the social variant is less accurate. (b) For an anchor truncated by the image boundary, social context improves localization. Attention weights indicate allocation, not causal importance.
Detector: DETRPose-S
JRDB coverage: 92.40%; NuScenes coverage: ∼ 90.1%
Social setting
JRDB ADE ↓
NuScenes ADE ↓
Without social
0.262
1.427
K=1
0.252
1.146
K=2
0.261
1.185
K=4
0.248
1.130
TABLE III: Maximum external-neighbor ablation for MoSoLoco-Trans.
Localization Model
Social
Params (M)
Size (MB)
Peak (MB)
GFLOPs
ADE ↓ (m)
Detector: DETRPose-S (11.5 M params; 46.9 MB; 32.42 GFLOPs)
Peak: 146.7 MB; coverage: 90.14%; FCOS3D uses its own detector
MonoLoco [ bertoni2019monoloco ]
✗
0.41
1.6
11.3
0.004
1.450
MonoTransmotion [ luan2025unified ]
✗
5.29
21.2
30.8
0.053
1.407
UniDepth V2 ViT-L [ 6 ]
✗
353.8
1415.3
2654.1
2650.56
0.935
FCOS3D R101 [ wang2021fcos3d ]
✗
55.0
219.8
621.3
682.50
0.901
TABLE IV: NuScenes 3D pedestrian-center localization. Params/Size report localizer FP32 cost; Peak/GFLOPs follow the resource protocol. FCOS3D performs its own detection; social models use K=4 .
Localization Model
Vanilla Transformer
OmniTraj [ 4 ]
Raw Forecast
Filtered
Raw Forecast
Filtered
ADE ↓
FDE ↓
ADE ↓
FDE ↓
ADE ↓
FDE ↓
ADE ↓
FDE ↓
Detector: DETRPose-S (Small)
GT-History Input
0.082
0.144
–
–
0.059
0.116
–
–
MonoLoco [ bertoni2019monoloco ]
0.283
0.364
0.244
0.304
0.250
0.271
0.218
0.226
MonoTransmotion [ luan2025unified ]
0.280
0.359
0.243
0.300
0.240
0.260
0.207
0.208
TABLE V: Controlled JRDB trajectory forecasting. MoSoLoco uses K=4 . OmniTraj reports best-of-20 minADE with FDE from the same mode. Each detector block uses its common retained cohort; filtering uses only observed history.
Fig. 4: JRDB forecasting example. Dashed trajectories are raw localization observations; dotted trajectories apply the future-blind filter only to observed history.
Model
Runtime
ADE ↓
FPS ↑
MoSoLoco-Trans
Baseline
0.248
6.31
Optimized
0.248
23.00
MoSoLoco-MLP
Baseline
0.254
6.97
Optimized
0.254
24.15
TABLE VI: Jetson AGX Xavier model-inference results on JRDB.
Relative camera pose is a basic geometric cue for visual re-localization and scene understanding. When using images alone, visual evidence may not sufficiently support reliable estimation of 3D-consistent motion. The challenge is especially acute in unfamiliar and ever-changing environments for real-time applications, where a system must infer spatial structure under tight time constraints from what it sees rather than rely on scene-specific reconstruction or training. This raises a fundamental question: how can live 3D camera motion be estimated accurately for re-localization in unseen environments while drawing on enough scene context to resolve pose ambiguity? We introduce MultiLoc, a multi-view-guided relative pose regressor trained at scale to achieve spatial and geometric consistent representations for robust visual re-localization in unseen scenarios with high inference speed. Specifically, MultiLoc creates a minimal 3D-sub-scene representation of the environment and efficiently transforms it into 3D spatially and geometrically consistent features in a single forward pass, enabling precise pose estimates with high inference speed gains. Across diverse indoor, outdoor, and in-the-wild visual re-localization benchmarks---Indoor6, Cambridge Landmarks and WaySpots---MultiLoc consistently outperforms state-of-the-art relative pose regression methods. We also highlight that MultiLoc, a pose regressor, also performs competitively with inference-heavy and structure-based approaches while retaining sub-second inference and generalizing to unseen scenes. Given a small posed support set, it also surpasses relative pose regression, feature-matching, and non-regression methods on several relative camera pose benchmarks. Code will be released.
Monocular egocentric human pose estimation is essential for ubiquitous activity monitoring. However, understanding the user's absolute location within the environment remains a challenge. Existing methods primarily focus on relative motion from an initial position, and tend not to account for the wearer's absolute location within an environment. Furthermore, inherent scale ambiguity in monocular vision leads to severe translational drift, limiting long-term tracking without specialized multi-sensor hardware. To address this, we propose MapMonoEgo, a novel framework achieving globally consistent human pose estimation solely from a monocular camera by leveraging a pre-scanned 3D point cloud. We also introduce AIST-Living dataset, a new dataset pairing egocentric video with ground-truth motion in a scanned environment. Experiments demonstrate that our approach significantly outperforms the state-of-the-art baseline, proving its utility for practical monitoring tasks without specialized hardware.
Hiroyuki Deguchi, Ryosuke Hori, Kotaro Amaya +3
1Keio University · 2National Institute of Advanced Industrial Science and Technology
3D human pose estimation is a key enabling technology for applications such as healthcare monitoring, human-robot collaboration, and immersive gaming, but real-world deployment remains challenged by viewpoint variations. Existing methods struggle to generalize to unseen camera viewpoints, require large amounts of training data, and suffer from high inference latency. We propose MoViD, a viewpoint-invariant 3D human pose estimation framework that disentangles viewpoint information from motion features. The key idea is to extract viewpoint information from intermediate pose features and leverage it to enhance both the robustness and efficiency of pose estimation. MoViD introduces a view estimator that models key joint relationships to predict viewpoint information, and an orthogonal projection module to disentangle motion and view features, further enhanced through physics-grounded contrastive alignment across views. For real-time edge deployment, MoViD employs a frame-by-frame inference pipeline with a view-aware strategy that adaptively activates flip refinement based on the estimated viewpoint. Evaluations on nine public datasets and newly collected multiview UAV and gait analysis datasets show that MoViD reduces pose estimation error by over 24.2% compared to state-of-the-art methods, maintains robust performance under severe occlusions with 60% less training data, and achieves real-time inference at 15 FPS on NVIDIA edge devices.
Yejia Liu, Hengle Jiang, Haoxian Liu +2
Department of Computer Science and Engineering, Hong Kong University of Science and Technology