Unlocking Vision-Language Models for Video Anomaly Detection via Fine-Grained Prompting

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Zou, Shu, Tian, Xinyu, Wesemann, Lukas, Waschkowski, Fabian, Yang, Zhaoyuan, Zhang, Jing
Format: Preprint
Publié: 2025
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866908573659824128
author Zou, Shu
Tian, Xinyu
Wesemann, Lukas
Waschkowski, Fabian
Yang, Zhaoyuan
Zhang, Jing
author_facet Zou, Shu
Tian, Xinyu
Wesemann, Lukas
Waschkowski, Fabian
Yang, Zhaoyuan
Zhang, Jing
contents Prompting has emerged as a practical way to adapt frozen vision-language models (VLMs) for video anomaly detection (VAD). Yet, existing prompts are often overly abstract, overlooking the fine-grained human-object interactions or action semantics that define complex anomalies in surveillance videos. We propose ASK-Hint, a structured prompting framework that leverages action-centric knowledge to elicit more accurate and interpretable reasoning from frozen VLMs. Our approach organizes prompts into semantically coherent groups (e.g. violence, property crimes, public safety) and formulates fine-grained guiding questions that align model predictions with discriminative visual cues. Extensive experiments on UCF-Crime and XD-Violence show that ASK-Hint consistently improves AUC over prior baselines, achieving state-of-the-art performance compared to both fine-tuned and training-free methods. Beyond accuracy, our framework provides interpretable reasoning traces towards anomaly and demonstrates strong generalization across datasets and VLM backbones. These results highlight the critical role of prompt granularity and establish ASK-Hint as a new training-free and generalizable solution for explainable video anomaly detection.
format Preprint
id arxiv_https___arxiv_org_abs_2510_02155
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unlocking Vision-Language Models for Video Anomaly Detection via Fine-Grained Prompting
Zou, Shu
Tian, Xinyu
Wesemann, Lukas
Waschkowski, Fabian
Yang, Zhaoyuan
Zhang, Jing
Computer Vision and Pattern Recognition
Artificial Intelligence
Prompting has emerged as a practical way to adapt frozen vision-language models (VLMs) for video anomaly detection (VAD). Yet, existing prompts are often overly abstract, overlooking the fine-grained human-object interactions or action semantics that define complex anomalies in surveillance videos. We propose ASK-Hint, a structured prompting framework that leverages action-centric knowledge to elicit more accurate and interpretable reasoning from frozen VLMs. Our approach organizes prompts into semantically coherent groups (e.g. violence, property crimes, public safety) and formulates fine-grained guiding questions that align model predictions with discriminative visual cues. Extensive experiments on UCF-Crime and XD-Violence show that ASK-Hint consistently improves AUC over prior baselines, achieving state-of-the-art performance compared to both fine-tuned and training-free methods. Beyond accuracy, our framework provides interpretable reasoning traces towards anomaly and demonstrates strong generalization across datasets and VLM backbones. These results highlight the critical role of prompt granularity and establish ASK-Hint as a new training-free and generalizable solution for explainable video anomaly detection.
title Unlocking Vision-Language Models for Video Anomaly Detection via Fine-Grained Prompting
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2510.02155