arXiv:2608.30230cs.AI2026-09

改进测试时提示调优的损失函数,让模型更懂自己的不确定性。

Rethinking the Test-Time Prompt Tuning Objective from the Perspective of Calibration

论文配图:Rethinking the Test-Time Prompt Tuning Objective from the Perspective of Calibration
图 1 · 摘自论文原文
  • 用增强视图构建目标分布,再与原图预测对齐
  • 引入目标分布熵的对抗项,保留样本不确定性
  • 在多个基准上同时提升准确率和校准性

测试时提示调优(TPT)通过在多个增强视图上最小化熵来优化每个测试样本的提示。然而,我们发现标准的熵最小化方法会促使模型产生过度自信的预测,忽略样本特异性不确定性,导致严重校准性能下降。为此,我们提出一种新目标:用交叉熵将原视图预测与由增强视图推导出的目标分布对齐,同时以对抗方式引入目标分布的熵,以捕捉样本级不确定性。为更好构建目标分布,我们根据置信度对每个增强视图的预测进行置信度感知温度缩放,增强高置信度预测,软化低置信度预测。该设计使模型仅在目标分布可靠时才提高置信度,而在预测冲突或模糊时保留不确定性。大量实验表明,本方法不仅达到顶尖准确率,还显著改善模型校准性。

原文摘要 · Abstract (English)

Test-time prompt tuning (TPT) has emerged as a powerful paradigm, refining prompts for each test sample via entropy minimization (EM) over multiple augmented views. However, we identify a limitation in the standard EM-based adaptation: it inherently drives the model toward overconfident predictions disregarding sample-specific uncertainty, leading to significant calibration degradation. To address these limitations, we propose a new objective that replaces the conventional EM loss by aligning the original-view prediction with a target distribution derived from augmented views via cross-entropy, while adversarially incorporating the entropy of the target distribution to capture sample-specific uncertainty. Furthermore, to better construct this target distribution, we apply confidence-aware temperature scaling to each augmented-view prediction according to its confidence, sharpening confident predictions while softening uncertain ones. This formulation allows the model to increase confidence only when the target distribution is reliable, while preserving uncertainty when it reflects ambiguous or conflicting augmented-view predictions. Extensive experiments across diverse benchmarks demonstrate that our approach not only achieves state-of-the-art accuracy but also significantly improves model calibration.

提示调优校准不确定性建模

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