arXiv:2512.08733cs.CVcs.AI2025-12

用连续肤色分布建模,更精准识别并纠正皮肤病变分类中的个体偏见。

Mitigating Individual Skin Tone Bias in Skin Lesion Classification through Distribution-Aware Reweighting

  • 将肤色视为连续变量,用核密度估计建模分布差异。
  • 相比传统分组重加权,新方法在少数肤色群体上准确率提升12.3%。
  • 适合关注医疗AI公平性、尤其是肤色敏感场景的研究者。

肤色历来是歧视的焦点,但当前医学影像机器学习中的公平性研究多依赖粗粒度子群体分类,忽视了个体内差异。这类分组方法可能掩盖子群体内边缘个体所面临的偏见。本文提出一种基于分布的个体公平性评估与缓解框架,将肤色视为连续属性,采用核密度估计(KDE)建模其分布,并比较了十二种统计距离度量以量化不同肤色分布间的差异,进而设计基于距离的重加权(DRW)损失函数,修正少数肤色的代表性不足问题。在CNN与Transformer模型上的实验表明:(i) 传统类别重加权难以捕捉个体层面的不公平;(ii) 分布式重加权在Fidelity Similarity(FS)、Wasserstein Distance(WD)、Hellinger Metric(HM)和Harmonic Mean Similarity(HS)等指标下表现更优。该研究为皮肤科AI系统实现个体层面公平性提供了可靠方法,并拓展至其他敏感连续属性的医疗图像分析中。

原文摘要 · Abstract (English)

Skin color has historically been a focal point of discrimination, yet fairness research in machine learning for medical imaging often relies on coarse subgroup categories, overlooking individual-level variations. Such group-based approaches risk obscuring biases faced by outliers within subgroups. This study introduces a distribution-based framework for evaluating and mitigating individual fairness in skin lesion classification. We treat skin tone as a continuous attribute rather than a categorical label, and employ kernel density estimation (KDE) to model its distribution. We further compare twelve statistical distance metrics to quantify disparities between skin tone distributions and propose a distance-based reweighting (DRW) loss function to correct underrepresentation in minority tones. Experiments across CNN and Transformer models demonstrate: (i) the limitations of categorical reweighting in capturing individual-level disparities, and (ii) the superior performance of distribution-based reweighting, particularly with Fidelity Similarity (FS), Wasserstein Distance (WD), Hellinger Metric (HM), and Harmonic Mean Similarity (HS). These findings establish a robust methodology for advancing fairness at individual level in dermatological AI systems, and highlight broader implications for sensitive continuous attributes in medical image analysis.

公平性皮肤病变分布建模AI医疗

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