广义长尾分类的特征空间目标识别算法

    Generalized feature augmentation:feature space object recognition algorithm for generalized long-tail classification

    • 摘要: 在实际情况中,数据集往往遵循长尾分布。为了缓解数据不平衡问题,通常可以采用重采样、重加权和数据扩增等方法,从而确保训练模型在各类别间具有相对一致的性能。当数据集中某些类别的样本数量不足,无法充分代表该类别时,需要依赖额外知识来恢复遗失的信息。目前存在的大多数长尾分类方法主要关注解决类别样本数不平衡的问题,而忽略了属性不平衡的情况。即使在类别平衡的情况下,属性分布仍可能呈现长尾形式,而广义长尾分类方法同时考虑了这两种不平衡情况。本研究提出一种新方法来解决广义长尾分布下样本代表性不足的问题,即通过学习充足样本类别和代表性不足样本类别的共有特征和类别特定特征,扩增后者类别的特征。提取与属性无关的不变特征,并利用类别权重层将该不变特征分解为类别共有成分和类别特定成分。在训练阶段,融合了未充分代表类别的类别特定特征和类别共有特征,以动态生成该类别的新样本。在广义长尾数据集ImageNet-GLT和MSCOCO-GLT上的实验结果显示出了较为先进的性能。

       

      Abstract: In practical scenarios, the frequencies of each class in a dataset typically differ, often following a long-tailed distribution. To alleviate data imbalance issues, methods such as resampling, re-weighting, and data augmentation are commonly employed to ensure relatively consistent performance across classes during model training. When samples for certain classes in the dataset are insufficient to adequately represent that class, additional knowledge is necessary to recover lost information. Most existing long-tail classification methods focus primarily on addressing imbalances in class sample sizes, while overlooking imbalances in attributes. However, even in scenarios of class balance, attribute distributions may exhibit long-tailed patterns, and generalized long-tail classification methods address both forms of imbalance simultaneously. This study proposed a novel approach to address the issue of inadequate sample representation in generalized long-tail distributions by augmenting features for underrepresented classes with shared and class-specific features learned from classes with sufficient samples. Specifically, invariant features unrelated to attributes were extracted and decomposed into class-shared and class-specific components using class activation maps. During training, the class-specific features for underrepresented classes were fused with class-shared features to dynamically generate new samples for those classes. Experimental results on generalized long-tailed datasets such as ImageNet-GLT and MSCOCO-GLT demonstrate advanced performance.

       

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