SkeFi: Cross-Modal Knowledge Transfer for Wireless Skeleton-Based Action Recognition

TL;DR

SkeFi introduces a novel cross-modal knowledge transfer framework that leverages RGB data to improve wireless sensor-based skeleton and action recognition, overcoming noise and data scarcity issues in non-invasive sensing modalities.

Contribution

The paper proposes SkeFi, a new method combining cross-modal transfer and enhanced temporal graph convolution to improve wireless skeleton-based action recognition.

Findings

Achieves state-of-the-art results on mmWave and LiDAR datasets.

Effectively handles noisy and incomplete skeletal data from wireless sensors.

Demonstrates robustness in challenging environments with privacy concerns.

Abstract

Skeleton-based action recognition leverages human pose keypoints to categorize human actions, which shows superior generalization and interoperability compared to regular end-to-end action recognition. Existing solutions use RGB cameras to annotate skeletal keypoints, but their performance declines in dark environments and raises privacy concerns, limiting their use in smart homes and hospitals. This paper explores non-invasive wireless sensors, i.e., LiDAR and mmWave, to mitigate these challenges as a feasible alternative. Two problems are addressed: (1) insufficient data on wireless sensor modality to train an accurate skeleton estimation model, and (2) skeletal keypoints derived from wireless sensors are noisier than RGB, causing great difficulties for subsequent action recognition models. Our work, SkeFi, overcomes these gaps through a novel cross-modal knowledge transfer method acquired from the data-rich RGB modality. We propose the enhanced Temporal Correlation Adaptive Graph Convolution (TC-AGC) with frame interactive enhancement to overcome the noise from missing or inconsecutive frames. Additionally, our research underscores the effectiveness of enhancing multiscale temporal modeling through dual temporal convolution. By integrating TC-AGC with temporal modeling for cross-modal transfer, our framework can extract accurate poses and actions from noisy wireless sensors. Experiments demonstrate that SkeFi realizes state-of-the-art performances on mmWave and LiDAR. The code is available at https://github.com/Huang0035/Skefi.