Most of the recent Deep Semantic Segmentation algorithms suffer from large generalization errors, even when powerful hierarchical representation models based on convolutional neural networks have been employed. This could be attributed to limited training data and large distribution gap in train and test domain datasets. In this paper, we propose a multi-level self-supervised learning model for domain adaptation of semantic segmentation. Exploiting the idea that an object (and most of the stuff given context) should be labeled consistently regardless of its location, we generate spatially independent and semantically consistent (SISC) pseudo-labels by segmenting multiple sub-images using base model and designing an aggregation strategy. Image level pseudo weak-labels, PWL, are computed to guide domain adaptation by capturing global context similarity in source and domain at latent space level. Thus helping latent space learn the representation even when there are very few pixels belonging to the domain category (small object for example) compared to rest of the image. Our multi-level Self-supervised learning (MLSL) outperforms existing state-of art (self or adversarial learning) algorithms. Specifically, keeping all setting similar and employing MLSL we obtain an mIoU gain of 5:1% on GTA-V to Cityscapes adaptation and 4:3% on SYNTHIA to Cityscapes adaptation compared to existing state-of-art method.

本文提出了一种基于多级自监督学习模型的语义分割域自适应方法，通过分割多个子图像来生成空间独立且语义一致的伪标签，并计算图像级伪弱标签来捕捉源域和目标域中的全局上下文相似性，从而在像素数很少（例如小物体）的情况下帮助潜在空间学习表示。该方法在GTA-V到Cityscapes和SYNTHIA到Cityscapes的适应中均取得了优于现有方法的性能表现。

MLSL: 多层次自监督学习，带有空间独立和语义一致标记的领域自适应