论文标题
HCSC:分层对比选择性编码
HCSC: Hierarchical Contrastive Selective Coding
论文作者
论文摘要
层次的语义结构自然存在于图像数据集中,其中几个语义相关的图像簇可以进一步整合到具有更粗的语义的较大群集中。用图像表示捕获此类结构可以极大地使对各种下游任务的语义理解。现有的对比表示学习方法缺乏如此重要的模型能力。此外,这些方法中使用的负对在语义上不能保证在语义上截然不同,这可能会进一步妨碍学习图像表示的结构正确性。为了应对这些局限性,我们提出了一个新颖的对比学习框架,称为层次对比选择性编码(HCSC)。在此框架中,构建了一组层次原型并动态更新,以表示潜在空间中数据的层次结构。为了使图像表示更好地拟合这样的语义结构,我们采用并进一步改善了通过精心设计的配对方案来改善传统实例和原型对比度学习。该方案旨在选择具有相似语义和更精确的负面对,具有真正不同语义的更精确的负面对。在广泛的下游任务中,我们验证了HCSC优于最先进的对比度方法,并且主要模型组件的有效性已通过丰富的分析研究证明。我们在第二节建立了一个全面的模型动物园。 D.我们的源代码和模型权重可从https://github.com/gyfastas/hcsc获得
Hierarchical semantic structures naturally exist in an image dataset, in which several semantically relevant image clusters can be further integrated into a larger cluster with coarser-grained semantics. Capturing such structures with image representations can greatly benefit the semantic understanding on various downstream tasks. Existing contrastive representation learning methods lack such an important model capability. In addition, the negative pairs used in these methods are not guaranteed to be semantically distinct, which could further hamper the structural correctness of learned image representations. To tackle these limitations, we propose a novel contrastive learning framework called Hierarchical Contrastive Selective Coding (HCSC). In this framework, a set of hierarchical prototypes are constructed and also dynamically updated to represent the hierarchical semantic structures underlying the data in the latent space. To make image representations better fit such semantic structures, we employ and further improve conventional instance-wise and prototypical contrastive learning via an elaborate pair selection scheme. This scheme seeks to select more diverse positive pairs with similar semantics and more precise negative pairs with truly distinct semantics. On extensive downstream tasks, we verify the superior performance of HCSC over state-of-the-art contrastive methods, and the effectiveness of major model components is proved by plentiful analytical studies. We build a comprehensive model zoo in Sec. D. Our source code and model weights are available at https://github.com/gyfastas/HCSC