Multitarget Domain Adaptation for Remote Sensing Classification Using Graph Neural Network

Abstract

Remote sensing deals with huge variations in geography, acquisition season, and a plethora of sensors. Considering the difficulty of collecting labeled data uniformly representing all scenarios, data-hungry deep learning models are often trained with labeled data in a source domain that is limited in the above-mentioned aspects. Domain adaptation (DA) methods can adapt such model for applying on target domains with different distributions from the source domain. However, most remote sensing DA methods are designed for single-target, thus requiring a separate target classifier to be trained for each target domain. To mitigate this, we propose multitarget DA in which a single classifier is learned for multiple unlabeled target domains. To build a multitarget classifier, it may be beneficial to effectively aggregate features from the labeled source and different unlabeled target domains. Toward this, we exploit coteaching based on the graph neural network that is capable of leveraging unlabeled data. We use a sequential adaptation strategy that first adapts on the easier target domains assuming that the network finds it easier to adapt to the closest target domain. We validate the proposed method on two different datasets, representing geographical and seasonal variation. Code is available at https://gitlab.lrz.de/ai4eo/da-multitarget-gnn/.