Recent weakly-supervised semantic segmentation (WSSS) has made remarkable progress due to class-wise localization techniques using image-level labels. Meanwhile, weakly-supervised instance segmentation (WSIS) is a more challenging task because instance-wise localization using only image-level labels is quite difficult. Consequently, most WSIS approaches exploit off-the-shelf proposal technique that requires pre-training with high-level labels, deviating a fully image-level supervised setting. Moreover, we focus on semantic drift problem, $i.e.,$ missing instances in pseudo instance labels are categorized as background class, occurring confusion between background and instance in training. To this end, we propose a novel approach that consists of two innovative components. First, we design a semantic knowledge transfer to obtain pseudo instance labels by transferring the knowledge of WSSS to WSIS while eliminating the need for off-the-shelf proposals. Second, we propose a self-refinement method that refines the pseudo instance labels in a self-supervised scheme and employs them to the training in an online manner while resolving the semantic drift problem. The extensive experiments demonstrate the effectiveness of our approach, and we outperform existing works on PASCAL VOC2012 without any off-the-shelf proposal techniques. Furthermore, our approach can be easily applied to the point-supervised setting, boosting the performance with an economical annotation cost. The code will be available soon.

本文提出一种创新的方法来解决弱监督实例分割任务中的实例定位难题，并使用自我训练方案来改进伪标注，消除语义漂移问题。通过在 PASCAL VOC 2012 和 MS COCO 上广泛实验，证明了该方法的有效性，无需使用与实例或对象有关的预先训练技术。

从语义到实例分割：通过语义知识转移和自我优化进行弱监督实例分割