Transformer-based Federated Learning for Multi-Label Remote Sensing Image Classification

TL;DR

This paper evaluates transformer architectures like MLP-Mixer, ConvMixer, and PoolFormer in federated learning for remote sensing multi-label classification, focusing on robustness to non-IID data and comparing their complexities and generalization abilities.

Contribution

It investigates the effectiveness of recent transformer models in federated remote sensing classification, providing guidelines for architecture selection under data heterogeneity.

Findings

Transformers improve generalization in federated remote sensing tasks.

Transformers have higher local training and aggregation complexities.

Transformers demonstrate robustness to non-IID data compared to ResNet-50.

Abstract

Federated learning (FL) aims to collaboratively learn deep learning model parameters from decentralized data archives (i.e., clients) without accessing training data on clients. However, the training data across clients might be not independent and identically distributed (non-IID), which may result in difficulty in achieving optimal model convergence. In this work, we investigate the capability of state-of-the-art transformer architectures (which are MLP-Mixer, ConvMixer, PoolFormer) to address the challenges related to non-IID training data across various clients in the context of FL for multi-label classification (MLC) problems in remote sensing (RS). The considered transformer architectures are compared among themselves and with the ResNet-50 architecture in terms of their: 1) robustness to training data heterogeneity; 2) local training complexity; and 3) aggregation complexity under different non-IID levels. The experimental results obtained on the BigEarthNet-S2 benchmark archive demonstrate that the considered architectures increase the generalization ability with the cost of higher local training and aggregation complexities. On the basis of our analysis, some guidelines are derived for a proper selection of transformer architecture in the context of FL for RS MLC. The code of this work is publicly available at https://git.tu-berlin.de/rsim/FL-Transformer.