Bridging Data Islands: Geographic Heterogeneity-Aware Federated Learning for Collaborative Remote Sensing Semantic Segmentation

Remote sensing semantic segmentation (RSS) is an essential task in Earth Observation missions. Due to data privacy concerns, high-quality remote sensing images with annotations cannot be well shared among institutions, making it difficult to fully utilize RSS data to train a generalized model. Federated Learning (FL), a privacy-preserving collaborative learning technology, is a potential solution. However, the current research on how to effectively apply FL in RSS is still scarce and requires further investigation. Remote sensing images in various institutions often exhibit strong geographical heterogeneity. More specifically, it is reflected in terms of class-distribution heterogeneity and object-appearance heterogeneity. Unfortunately, most existing FL studies show inadequate focus on geographical heterogeneity, thus leading to performance degradation in the global model. Considering the aforementioned issues, we propose a novel Geographic Heterogeneity-Aware Federated Learning (GeoFed) framework to address privacy-preserving RSS. Through Global Feature Extension and Tail Regeneration modules, class-distribution heterogeneity is alleviated. Additionally, we design an Essential Feature Mining strategy to alleviate object-appearance heterogeneity by constructing essential features. Extensive experiments on three datasets (i.e., FBP, CASID, Inria) show that our GeoFed consistently outperforms the current state-of-the-art methods. The code will be available publicly.