Unsupervised Domain Adaptation VIA Cluster Alignment with Maximum Classifier Discrepancy

Mohamed Azzam, Si Wu, Aurele Tohokantche Gnanha, Qianfen Jiao, Hau-San Wong

Abstract: One way of addressing the problem of unsupervised domain adaptation (UDA) is to perform adversarial training between two classifiers and their shared feature extractor. The two classifiers are enforced to detect the misaligned regions between the source and target domains, while the feature extractor aligns the features by confusing the classifiers. Although this method yields improvement, it ignores the relationship among target neighbors, which may consequently limit the model performance. In this work, we propose a new alignment strategy based on the "cluster assumption" to ensure the aligned target features preserve their clusters by avoiding overlap with decision boundaries. Furthermore, to make the aligned features more compact, we constrain them to be ro-bust against adversarial perturbation using the different views of the classifiers. Extensive experiments demonstrate the effectiveness of our solution on various datasets.