Category-Specific Selective Feature Enhancement for Long-Tailed Multi-Label Image Classification

Since real-world multi-label data often exhibit significant label imbalance, long-tailed multi-label image classification has emerged as a prominent research area in computer vision. Traditionally, it is considered that deep neural networks' classifiers are vulnerable to long-tailed distributions, whereas the feature extraction backbone remains relatively robust. However, our analysis from the feature learning perspective reveals that the backbone struggles to maintain high sensitivity to sample-scarce categories but retains the ability to localize specific areas effectively. Based on this observation, we propose a new model for long-tailed multi-label image classification named category-specific selective feature enhancement (CSSFE). First, it utilizes the retained localization capability of the backbone to capture label-dependent class activation maps. Then, a progressive attention enhancement mechanism, updating from head to medium to tail categories, is introduced to address the lowconfidence issue in medium and tail categories. Finally, visual features are extracted according to the optimized class activation maps and combined with semantic information to perform the classification task. Extensive experiments on two benchmark datasets highlight our findings' generalizability and the proposed CSSFE's superior performance. Our code is available at https://github.com/TangXu-Group/multilabelRSSC/tree/main/CSSFE.