用姿态可靠性校准异常检测分数,提升视频异常识别准确率。
Reliability-Aware Prototype Calibration for Frozen Pose-Flow Video Anomaly Detection

- 基于姿态流特征空间的原型偏差修正得分,结合置信度门控。
- 在8组实验中平均提升帧级AUROC 2.03个百分点,最高达4.49。
- 适用于无法重训练的冻结模型系统,轻量且易部署。
姿态流视频异常检测器因其提供基于似然的轨迹排序,在单类监控中具有吸引力。然而单一似然分数可能掩盖多模态正常行为,并对姿态观测噪声敏感。本文研究冻结检测器设置,即姿态流主干、缓存的姿态轨迹与评估流程固定不变。提出一种后处理校准方法——可靠性感知原型校准(RPC),在标准化流得分基础上,加入标准化最近原型偏差,并仅以关键点置信度作为门控机制控制该几何证据的引入。该方法在保留原始密度信号的同时,利用经验正常模式结构修正排序。在两个冻结姿态流主干和四个数据集上,所有八组配置均取得提升,帧级AUROC提升0.34至4.49个百分点,平均提升2.03点。消融与可靠性分析表明,原型偏差是主要修正信号,而置信度门控在姿态观测不可靠时尤为有效。结果表明,轻量级后处理校准可在无法重训练或复现完整姿态流水线时显著增强已缓存的姿态流系统。
原文摘要 · Abstract (English)
Pose-flow video anomaly detectors are attractive for one-class surveillance because they provide likelihood-based rankings for tracked skeleton windows. However, a single likelihood score may hide multimodal normal behavior and be sensitive to pose-observation noise. We study a frozen-detector setting in which the pose-flow backbone, cached skeleton tracks, and evaluation pipeline are fixed. Reliability-Aware Prototype Calibration (RPC) is a post-hoc score calibration method for this setting. It adds a standardized nearest-prototype deviation in the frozen latent space to the standardized flow score, and uses keypoint confidence only to gate this added geometric evidence. Thus, RPC preserves the original density signal while correcting the ranking with empirical normal-mode structure under pose reliability. Across two frozen pose-flow backbones and four datasets, RPC improves frame-level AUROC in all eight backbone-dataset pairs, with gains ranging from 0.34 to 4.49 percentage points and averaging 2.03 points. Ablation and reliability analyses show that prototype deviation is the main corrective signal, while reliability gating is most useful when pose observations are less trustworthy. These results suggest that lightweight post-hoc calibration can strengthen cached pose-flow systems when retraining or reproducing the full pose pipeline is impractical.
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