*Article* **Deep Open-Set Domain Adaptation for Cross-Scene Classification based on Adversarial Learning and Pareto Ranking**

#### **Reham Adayel, Yakoub Bazi \*, Haikel Alhichri and Naif Alajlan**

Computer Engineering Department, College of Computer and Information Sciences, King Saud University, Riyadh 11543, Saudi Arabia; 437204127@student.ksu.edu.sa (R.A.); hhichri@ksu.edu.sa (H.A.); najlan@ksu.edu.sa (N.A.)

**\*** Correspondence: ybazi@ksu.edu.sa; Tel.: +966-114696297

Received: 28 April 2020; Accepted: 25 May 2020; Published: 27 May 2020

**Abstract:** Most of the existing domain adaptation (DA) methods proposed in the context of remote sensing imagery assume the presence of the same land-cover classes in the source and target domains. Yet, this assumption is not always realistic in practice as the target domain may contain additional classes unknown to the source leading to the so-called open set DA. Under this challenging setting, the problem turns to reducing the distribution discrepancy between the shared classes in both domains besides the detection of the unknown class samples in the target domain. To deal with the openset problem, we propose an approach based on adversarial learning and pareto-based ranking. In particular, the method leverages the distribution discrepancy between the source and target domains using min-max entropy optimization. During the alignment process, it identifies candidate samples of the unknown class from the target domain through a pareto-based ranking scheme that uses ambiguity criteria based on entropy and the distance to source class prototype. Promising results using two cross-domain datasets that consist of very high resolution and extremely high resolution images, show the effectiveness of the proposed method.

**Keywords:** scene classification; open-set domain adaptation; adversarial learning; min-max entropy; pareto ranking
