arXiv:2510.09452cs.LG2025-10

提出统一异常检测的新型流模型,提升稳定性和精度

On Uniformly Scaling Flows: A Density-Aligned Approach to Deep One-Class Classification

  • 用恒定雅可比行列式流连接一类分类与密度估计
  • 训练时自动防表征坍塌,负对数似然与潜在范数更对齐
  • 可直接替换现有模型,图像和像素级检测均表现更优

无监督异常检测通常基于两类主流范式:以 Deep SVDD 为代表的深度一类分类法学习正常数据的紧凑潜在表示,而归一化流则直接建模正常数据的概率密度。本文表明,均匀缩放流(USF)——即雅可比行列式恒定的归一化流——恰好连接了这两种方法。我们证明,通过最大似然训练 USF 等价于一个具有独特正则化的 Deep SVDD 目标,该正则化能天然防止表征坍塌。这一理论桥梁意味着 USF 同时继承了流模型的密度保真性与一类方法的距离推理能力。进一步实验显示,相比 Deep SVDD 和非均匀缩放流,USF 能实现更紧密的负对数似然与潜在范数对齐,并自然扩展近期结合一类目标与变分自编码器的混合方法。因此,我们主张将 USF 作为现代异常检测架构中非 USF 的即插即用替代品。实证结果表明,该替换在多个基准测试和模型主干上均带来一致性能提升和显著增强的训练稳定性,涵盖图像级与像素级检测任务。此项工作统一了两大异常检测范式,推动了理论理解与实际性能的双重进展。

原文摘要 · Abstract (English)

Unsupervised anomaly detection is often framed around two widely studied paradigms. Deep one-class classification, exemplified by Deep SVDD, learns compact latent representations of normality, while density estimators realized by normalizing flows directly model the likelihood of nominal data. In this work, we show that uniformly scaling flows (USFs), normalizing flows with a constant Jacobian determinant, precisely connect these approaches. Specifically, we prove how training a USF via maximum-likelihood reduces to a Deep SVDD objective with a unique regularization that inherently prevents representational collapse. This theoretical bridge implies that USFs inherit both the density faithfulness of flows and the distance-based reasoning of one-class methods. We further demonstrate that USFs induce a tighter alignment between negative log-likelihood and latent norm than either Deep SVDD or non-USFs, and how recent hybrid approaches combining one-class objectives with VAEs can be naturally extended to USFs. Consequently, we advocate using USFs as a drop-in replacement for non-USFs in modern anomaly detection architectures. Empirically, this substitution yields consistent performance gains and substantially improved training stability across multiple benchmarks and model backbones for both image-level and pixel-level detection. These results unify two major anomaly detection paradigms, advancing both theoretical understanding and practical performance.

异常检测归一化流一类分类

Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。