Weakly-Supervised Domain Adaptive Semantic Segmentation With Prototypical Contrastive Learning
Authors: Anurag Das, Yongqin Xian, Dengxin Dai, Bernt Schiele

There has been a lot of effort in improving the performance of unsupervised domain adaptation for semantic segmentation task, however there is still a huge gap in performance when compared with supervised learning. In this work, we propose a common framework to use different weak labels, e.g. image, point and coarse labels from target domain to reduce this performance gap. Specifically, we propose to learn better prototypes that are representative class features, by exploiting these weak labels. We use these improved prototypes for contrastive alignment of class features. In particular, we perform two different feature alignments, first, we align pixel features with prototypes within each domain and second, we align pixel features from source to prototype of target domain in an asymmetric way. This asymmetric alignment is beneficial as it preserves the target features during training, which is essential when weak labels are available from target domain. Our experiments on standard benchmarks shows that our framework achieves significant improvement compared to existing works and is able to reduce the performance gap with supervised learning.