Asynchronous Federated Learning in UAV Swarms for Real-Time Image Recognition

Unmanned Aerial Vehicles (UAVs) with high mobility and flexibility have emerged as key enablers of computer vision (CV) applications. In the field of image recognition, federated learning can be integrated into UAV swarms, enabling distributed computing and efficient data sharing to train and deploy high-performance real-time image recognition models, while preserving the privacy of the UAV local data. However, despite its potential, federated learning in UAV swarms for real-time image recognition faces significant challenges of low convergence speed and insufficient model recognition accuracy posed by volatile environments. On the one hand, unstable UAV communication channels increase model upload latency. On the other hand, dynamic UAV states lead to fluctuations in local update quality. To address these challenges, we propose an accelerated asynchronous federated learning framework for UAV swarms to support real-time image recognition. Our framework introduces a Shapley-based asynchronous update mechanism, which enhances model accuracy by quantifying UAV update contributions and mitigating the effects of model staleness. Furthermore, we propose a fine-grained client selection strategy that accelerates convergence by selecting UAVs with low latency and high contributions to model recognition accuracy. A time-varying multi-armed bandit (MAB) model is employed to capture dynamic UAV states, optimizing client selection and further improving convergence. Numerical results in the simulated volatile environment show that our scheme outperforms benchmark methods in accuracy and convergence speed of the image recognition model.