From Distance to Direction: Structure-aware Label-specific Feature Fusion for Label Distribution Learning
Suping Xu, Chuyi Dai, Lin Shang, Changbin Shao, Xibei Yang, Witold Pedrycz
TL;DR
This work tackles label ambiguity in LDL by extending prototype-based label-specific features with Structural Anchor Points (SAPs) to model cross-cluster interactions. It introduces LIFT-SAP, which augments distance and directional information relative to SAPs, and LDL-LIFT-SAP, a two-stage framework that fuses predictions from multiple LSF spaces into a cohesive label distribution. Through extensive experiments on 15 real-world LDL datasets, the authors demonstrate that LIFT-SAP outperforms LIFT, and LDL-LIFT-SAP surpasses seven strong baselines across diverse metrics. The approach highlights the value of structure-aware, multi-perspective feature representations for more accurate and robust LDL in practical applications.
Abstract
Label distribution learning (LDL) is an emerging learning paradigm designed to capture the relative importance of labels for each instance. Label-specific features (LSFs), constructed by LIFT, have proven effective for learning tasks with label ambiguity by leveraging clustering-based prototypes for each label to re-characterize instances. However, directly introducing LIFT into LDL tasks can be suboptimal, as the prototypes it collects primarily reflect intra-cluster relationships while neglecting cross-cluster interactions. Additionally, constructing LSFs using multi-perspective information, rather than relying solely on Euclidean distance, provides a more robust and comprehensive representation of instances, mitigating noise and bias that may arise from a single distance perspective. To address these limitations, we introduce Structural Anchor Points (SAPs) to capture inter-cluster interactions. This leads to a novel LSFs construction strategy, LIFT-SAP, which enhances LIFT by integrating both distance and directional information of each instance relative to SAPs. Furthermore, we propose a novel LDL algorithm, Label Distribution Learning via Label-specifIc FeaTure with SAPs (LDL-LIFT-SAP), which unifies multiple label description degrees predicted from different LSF spaces into a cohesive label distribution. Extensive experiments on 15 real-world datasets demonstrate the effectiveness of LIFT-SAP over LIFT, as well as the superiority of LDL-LIFT-SAP compared to seven other well-established algorithms.
