Conventional multi-label classification (MLC) methods assume that all samples are fully labeled and identically distributed. Unfortunately, this assumption is unrealistic in large-scale MLC data that has long-tailed (LT) distribution and partial labels (PL). To address the problem, we introduce a novel task, Partial labeling and Long-Tailed Multi-Label Classification (PLT-MLC), to jointly consider the above two imperfect learning environments. Not surprisingly, we find that most LT-MLC and PL-MLC approaches fail to solve the PLT-MLC, resulting in significant performance degradation on the two proposed PLT-MLC benchmarks. Therefore, we propose an end-to-end learning framework: \textbf{CO}rrection $\rightarrow$ \textbf{M}odificat\textbf{I}on $\rightarrow$ balan\textbf{C}e, abbreviated as \textbf{\method{}}. Our bootstrapping philosophy is to simultaneously correct the missing labels (Correction) with convinced prediction confidence over a class-aware threshold and to learn from these recall labels during training. We next propose a novel multi-focal modifier loss that simultaneously addresses head-tail imbalance and positive-negative imbalance to adaptively modify the attention to different samples (Modification) under the LT class distribution. In addition, we develop a balanced training strategy by distilling the model's learning effect from head and tail samples, and thus design a balanced classifier (Balance) conditioned on the head and tail learning effect to maintain stable performance for all samples. Our experimental study shows that the proposed \method{} significantly outperforms general MLC, LT-MLC and PL-MLC methods in terms of effectiveness and robustness on our newly created PLT-MLC datasets.

本文介绍了一种新颖的任务，即Partial labeling and Long-Tailed Multi-Label Classification（PLT-MLC），并提出了一种端到端的学习框架CO-MIC-Balance（Correction，Modification，Balance），用于同时解决长尾分布和部分标签的多标签分类问题，该框架通过比较预测置信度和类特定阈值来修正丢失的标签，使用多聚焦的修饰符损失来同时解决头部尾部不平衡和正负不平衡，并使用平衡分类器来保持所有样本的稳定性。实验结果表明，该方法在新创建的PLT-MLC数据集上具有更高的有效性和鲁棒性。

不完美环境下的学习：长尾分布和部分标签的多标签分类