School of Electronic and Information Engineering South China University of Technology Guangzhou Guangdong 510641 China
Peng Cheng Laboratory Shenzhen Guangdong 518000 China
无监督域适应解决了在未标记的目标域中对数据进行分类的问题,给定标记的源域数据共享一个公共标签空间但遵循不同的分布。大多数最近的方法都采用显式对齐两个域之间的特征分布的方法。不同的是,在域适应性的基本假设的推动下,我们将域适应问题重新转换为目标数据的判别聚类,给定密切相关的标记源数据提供的强特权信息。从技术上讲,我们使用基于熵最小化的稳健变体的聚类目标,该变体自适应地过滤目标数据、类似 Fisher 的软标准以及通过质心分类的聚类排序。为了提取用于目标聚类的判别源信息,我们建议在标记的源数据上使用并行的、有监督的学习目标来联合训练网络。我们将用于域适应的蒸馏判别聚类方法称为 DisClusterDA。我们还给出了几何直觉,说明了 DisClusterDA 的组成目标如何帮助学习分类明智的纯、紧凑的特征分布。我们对五个流行的基准数据集进行了仔细的消融研究和广泛的实验,其中包括一个多源域适应数据集。基于常用的骨干网络,DisClusterDA 在这些基准上优于现有方法。有趣的是,在我们的 DisClusterDA 框架中,
Unsupervised domain adaptation addresses the problem of classifying data in an unlabeled target domain, given labeled source domain data that share a common label space but follow a different distribution. Most of the recent methods take the approach of explicitly aligning feature distributions between the two domains. Differently, motivated by the fundamental assumption for domain adaptability, we re-cast the domain adaptation problem as discriminative clustering of target data, given strong privileged information provided by the closely related, labeled source data. Technically, we use clustering objectives based on a robust variant of entropy minimization that adaptively filters target data, a soft Fisher-like criterion, and additionally the cluster ordering via centroid classification. To distill discriminative source information for target clustering, we propose to jointly train the network using parallel, supervised learning objectives over labeled source data. We term our method of distilled discriminative clustering for domain adaptation as DisClusterDA. We also give geometric intuition that illustrates how constituent objectives of DisClusterDA help learn class-wisely pure, compact feature distributions. We conduct careful ablation studies and extensive experiments on five popular benchmark datasets, including a multi-source domain adaptation one. Based on commonly used backbone networks, DisClusterDA outperforms existing methods on these benchmarks. It is also interesting to observe that in our DisClusterDA framework, adding an additional loss term that explicitly learns to align class-level feature distributions across domains does harm to the adaptation performance, though more careful studies in different algorithmic frameworks are to be conducted.