MATRIX-HAR: Lightweight Event-Based Human Action Recognition

A lightweight temporal motion-guided network with adaptive temporal resolution, hierarchical transfer learning, and post-training quantisation.

Expert Systems With Applications · Volume 303 · Article 130628 · 2026

Muhammad Hamza Zafar, Syed Kumayl Raza Moosavi, and Filippo Sanfilippo

Project overview

MATRIX-HAR is designed for event-based human action recognition under variable environmental conditions and limited computing resources. Its Adaptive Temporal Resolution module changes temporal granularity according to the input, while the Motion Guided Feature Module exploits motion information already encoded in the event stream.

Core contributions

  • Adaptive Temporal Resolution for input-dependent temporal processing.
  • A Motion Guided Feature Module that emphasizes intrinsic motion patterns in event streams.
  • Four hierarchical transfer-learning strategies from simpler to more challenging conditions.
  • Post-training quantisation for compact edge deployment with limited performance loss.

Reported evidence

97.82%accuracy on HARDVS
4×reported model compression after quantisation
22.3%relative improvement from comprehensive feature transfer

The paper reports 97.23% on PAF, 95.73% on THU-E-ACT-50, and 65.8% on THU-E-ACT-50 CHL. The reported gains over prior methods are 0.71, 0.74, 3.03, and 7.3 percentage points on the four datasets, respectively.

Datasets and evaluation

  • HARDVS for large-scale event-based human action recognition.
  • PAF for pedestrian, action, and fall-related event sequences.
  • THU-E-ACT-50 for controlled event-based action recognition.
  • THU-E-ACT-50 CHL for evaluation under more challenging environmental conditions.

Relevance to human-in-the-loop robotics

Human-in-the-loop robots need action understanding that is fast enough for interaction and compact enough for edge hardware. MATRIX-HAR directly targets both requirements while also studying how knowledge transfers from easier laboratory conditions to harder operating environments.