Training a Convolutional Neural Network (CNN) for semantic segmentation typically requires to collect a large amount of accurate pixel-level annotations, a hard and expensive task. In contrast, simple image tags are easier to gather. With this paper we introduce a novel weakly-supervised semantic segmentation model able to learn from image labels, and just image labels. Our model uses the prior knowledge of a network trained for image recognition, employing these image annotations, as an attention mechanism to identify semantic regions in the images. We then present a methodology that builds accurate class-specific segmentation masks from these regions, where neither external objectness nor saliency algorithms are required. We describe how to incorporate this mask generation strategy into a fully end-to-end trainable process where the network jointly learns to classify and segment images. Our experiments on PASCAL VOC 2012 dataset show that exploiting these generated class-specific masks in conjunction with our novel end-to-end learning process outperforms several recent weakly-supervised semantic segmentation methods that use image tags only, and even some models that leverage additional supervision or training data.

本文介绍了一种使用图像标签进行弱监督语义分割的模型，利用图像标注作为注意机制来识别图像中的语义区域，并描述了如何将此掩模生成策略纳入完全端到端可训练的过程中，其中网络同时学习对图像进行分类和分割，实验表明，利用生成的类特定掩模可以超越只使用图像标记的最新弱监督语义分割方法甚至某些利用额外监督或训练数据的模型。

利用先验网络知识学习弱监督语义分割