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Lin CHEN (Leen)

A Ph.D. candidate in the DSA Thrust at HKUST(GZ).

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Sensing Life in Stillness: Unified Dynamic and Static Human Mesh Reconstruction with mmWave Radar

Lin Chen, Cong Li, Shuxin Zhong, Jun Chen, Yufei Wen, Haotian Song, Kaishun Wu

IMWUT, 2026

mmRehab continuous rehabilitation monitoring across home and hospital environments
mmRehab turns everyday spaces into continuous, contactless rehabilitation monitoring environments.

A visual tour of how mmRehab reconstructs dynamic and static human meshes from COTS mmWave radar by treating the tiny motions inside stillness as useful physiological signal.

24%+lower 3D reconstruction error across dynamic and static rehabilitation tasks
4.75 cmaverage vertex error for static postures after static feature extraction
331.3 msend-to-end inference latency for continuous monitoring
0wearables or cameras required for radar-only reconstruction
Depth image generation from a 3D SMPL mesh

Data Synthesis

Depth projection bridges mesh geometry and radar learning

The method uses depth images rendered from 3D SMPL meshes as an intermediate geometric representation, giving the teacher network dense body-structure cues before distilling them into the radar model.

Static clutter removal effect on range-Doppler and range-azimuth maps

Macro-Motion Feature Extraction

Static clutter removal clarifies dynamic targets

For moving users, SCR suppresses strong zero-Doppler reflections from static objects, making the dynamic range-Doppler and range-azimuth responses cleaner for downstream macro-motion analysis.

Combined figure showing RAM, RDM, static clutter, SRAM, and RMDM for static user detection

Micro-Motion Feature Extraction

Static user detection is a multi-stage visual story

In still scenes, raw RAM/RDM and static clutter alone cannot identify the human target. Beamforming separates static targets into SRAM, while range-micro-Doppler exposes the subtle living signal that localizes the static user.

mmRehab radar alignment network and geometric prior network

Model

GPN supervises RAN through geometry-aware distillation

The Geometric Prior Network learns from depth-derived structure during training, while the Radar Alignment Network performs radar-only inference for dynamic and static mesh reconstruction.

Dynamic rehabilitation motions and static postures used in evaluation

Dataset

The evaluation covers both motions and held postures

The dataset includes dynamic rehabilitation actions such as arm/leg movement and walking, plus static postures such as standing, sitting, bow step, and single-leg support.

Overall performance comparison across dynamic motions and static postures

Evaluation

Overall results are paired across dynamic and static cases

The page now mirrors the paper's comparison: dynamic and static reconstruction metrics are shown together so readers can see that the same system improves both motion tracking and still-posture reconstruction.

Mesh estimation examples for users unseen during training

Generalization

Meshes remain plausible for unseen users

Qualitative examples compare video frames, ground truth meshes, baseline estimates, and mmRehab outputs, showing better limb orientation and body geometry across users excluded from training.

Mesh estimation examples for postures unseen during training

Generalization

Unseen posture examples expose the static-pose gain

The qualitative unseen-posture figure shows where the baseline struggles with arm motion and sitting posture, while mmRehab preserves more realistic articulation and static body configuration.

Generalization performance on unseen users for dynamic and static cases

Cross-User

Unseen-user metrics are shown as a pair

Dynamic and static results are grouped together to match the paper's generalization analysis.

Intra-limb and cross-limb unseen posture generalization results

Unseen Postures

Unseen-posture testing covers two transfer settings

The intra-limb and cross-limb settings summarize how well mmRehab generalizes beyond motions and postures observed during training.

Hall, meeting room, and living room experimental setups

Deployment

Evaluation spans practical indoor environments

The actual environment figure uses hall, meeting-room, and living-room setups, each with different clutter, furniture layout, and multipath conditions.

Radar-subject orientation settings used in robustness evaluation

Robustness

Orientation robustness is explicitly tested

The robustness section evaluates non-frontal sensing at 30, 60, and 90 degrees, showing where side-facing reflections begin to degrade mesh estimation.

Why static postures matter

Balance, endurance, and postural control are often expressed while the patient is holding still, so monitoring only large motion misses clinically meaningful recovery signals.

Why radar is attractive

mmWave sensing is contactless, privacy-preserving, and independent of lighting, making it a useful complement to camera- and wearable-based rehabilitation systems.

Where the limits appear

The paper reports strongest performance at shorter ranges and frontal or moderate orientations, with degradation at longer distances and larger side-facing angles.

Citation

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@article{chen2026sensing,
title = {Sensing Life in Stillness: Unified Dynamic and Static Human Mesh Reconstruction with mmWave Radar},
author = {Chen, Lin and Li, Cong and Zhong, Shuxin and Chen, Jun and Wen, Yufei and Song, Haotian and Wu, Kaishun},
journal = {Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies},
year = {2026},
doi = {10.1145/3790117}
}