arXiv:2511.20960stat.MLcs.LG2025-11

为神经网络输出设计几何校准与不确定性判断机制,让模型学会识别哪些预测不可靠。

Geometric Calibration and Neutral Zones for Uncertainty-Aware Multi-Class Classification

  • 用概率单纯形上的几何方法,实现多分类校准和个体预测不确定性量化
  • 实测可捕获72.5%错误,仅需人工复核34.5%样本,误判率从16.8%降至6.9%
  • 适合需要高可靠性决策的场景,如医疗诊断、安全关键系统

现代人工智能系统虽做出关键决策,但对不确定预测常无声失效——即使校准良好的模型也无法指出具体哪些预测不可靠。本文提出一种几何框架,同时解决神经网络概率输出的校准与实例级不确定性量化问题。将概率向量视为带费舍尔-罗伊度量的 (c−1) 维概率单纯形上的点,构建:(i) 加性对数比(ALR)校准映射,二分类时退化为Platt缩放,自然扩展至多分类;(ii) 几何可靠性评分,将校准后的概率转化为可操作的不确定性度量,支持对模糊预测进行合理人工介入。理论贡献包括:通过M估计理论证明校准估计器以 $O_p(n^{-1/2})$ 速率一致(定理1),以及可靠性评分的紧浓度界,给出显式亚高斯参数以指导验证集规模设计(定理2)。基于巴塔查里亚系数的联系,我们猜想中立区构造具有奈曼-皮尔逊最优性。在腺相关病毒分类任务上的实证表明,该两阶段框架捕获72.5%错误,仅需推迟34.5%样本,使自动化决策错误率从16.8%降至6.9%。值得注意的是,仅校准带来边际精度提升;真正效益来自可靠性评分机制,适用于任何校准过的概率输出。本工作融合信息几何与统计学习,为需严格验证的应用提供不确定性感知分类的形式保证。

原文摘要 · Abstract (English)

Modern artificial intelligence systems make critical decisions yet often fail silently when uncertain -- even well-calibrated models provide no mechanism to identify \textit{which specific predictions} are unreliable. We develop a geometric framework addressing both calibration and instance-level uncertainty quantification for neural network probability outputs. Treating probability vectors as points on the $(c-1)$-dimensional probability simplex equipped with the Fisher--Rao metric, we construct: (i) Additive Log-Ratio (ALR) calibration maps that reduce exactly to Platt scaling for binary problems while extending naturally to multi-class settings, and (ii) geometric reliability scores that translate calibrated probabilities into actionable uncertainty measures, enabling principled deferral of ambiguous predictions to human review. Theoretical contributions include: consistency of the calibration estimator at rate $O_p(n^{-1/2})$ via M-estimation theory (Theorem~1), and tight concentration bounds for reliability scores with explicit sub-Gaussian parameters enabling sample size calculations for validation set design (Theorem~2). We conjecture Neyman--Pearson optimality of our neutral zone construction based on connections to Bhattacharyya coefficients. Empirical validation on Adeno-Associated Virus classification demonstrates that the two-stage framework captures 72.5\% of errors while deferring 34.5\% of samples, reducing automated decision error rates from 16.8\% to 6.9\%. Notably, calibration alone yields marginal accuracy gains; the operational benefit arises primarily from the reliability scoring mechanism, which applies to any well-calibrated probability output. This work bridges information geometry and statistical learning, offering formal guarantees for uncertainty-aware classification in applications requiring rigorous validation.

不确定性量化概率校准信息几何

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