RaStream: Edge-Deployable Streaming Human Mesh Recovery from mmWave Radar

Abstract

Millimeter-wave (mmWave) radar enables privacy-preserving human sensing for edge applications, but streaming SMPL-X recovery on edge devices requires accurate spatial evidence extraction and temporally stable predictions under lightweight causal inference. Sparse radar reflections make dense mesh recovery difficult, and heavy multi-scale spatial backbones can be costly for volumetric radar tensors while still diluting weak body evidence with background clutter. Frame-wise mesh estimates further exhibit jitter, while generic temporal models often mix slowly varying body morphology with fast pose and translation dynamics. We present RaStream, an edge-deployable radar-tensor streaming mesh recovery framework that combines a radar-aware spatial encoder with dual-state causal temporal refinement. The Radar-aware Spatial Structure (RaSS) encoder preserves 3D radar structure, localizes the subject, extracts body-centered evidence, and produces compact radar-aware tokens from short radar windows. The dual-state temporal module separates slow morphology state from fast motion state: it accumulates morphology evidence for shape and gender estimation through a token-conditioned update gate and tracks dynamic motion with a causal recurrent state. The resulting model keeps streaming memory fixed and avoids full-volume buffering. We formulate temporal sampling parameters $(T_w, T, s)$ that expose radar observation density, finite unroll horizon, warm-up/replay behavior, and output-rate tradeoffs, and evaluate reconstruction accuracy, temporal smoothness, and edge efficiency on M4Human. RaSS-Base reduces single-window MVE from 90.90 mm to 84.27 mm over RT-Mesh with fewer parameters, while RaStream further reduces MVE to 72.05 mm under the random-split protocol. Jetson Orin Nano profiling shows 26.93 ms FP32 latency for the Base configuration.