COPRA: Conditional Parameter Adaptation with Reinforcement Learning for Video Anomaly Detection

Fuente: arXiv
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Autori principali: Jacob, Darryl Cherian, Liu, Xinyu, Wang, Kai, He, Pan
Natura: Preprint
Pubblicazione: 2026
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author Jacob, Darryl Cherian
Liu, Xinyu
Wang, Kai
He, Pan
author_facet Jacob, Darryl Cherian
Liu, Xinyu
Wang, Kai
He, Pan
contents Vision-language models (VLMs) have shown strong performance in video anomaly detection (VAD) while providing interpretable predictions. However, existing VLM-based VAD methods suffer from a fundamental mismatch between training and inference in both data distribution and model configuration. First, most approaches rely on static post-training adaptation, limiting generalization under distribution shifts such as unseen environments or anomaly types. Second, they train VLMs on sparse frames from long videos, but perform inference on densely sampled short segments, creating inconsistencies between training and testing. To address these limitations, we propose COPRA, a conditional parameter adaptation framework for VLM-based VAD. Instead of fixed prompts or shared parameter updates, COPRA generates input-specific parameter updates to dynamically adapt a frozen VLM for each video segment during both training and inference. Experiments show strong performance on standard VAD benchmarks, consistently outperforming static baselines in both in-domain and cross-domain settings. Moreover, COPRA generalizes beyond VAD to unseen tasks such as multiple-choice Video Question Answering and Dense Captioning. These results highlight COPRA as an effective weight-space generation framework for scalable, adaptive, and context-aware video understanding. The code will be released at https://github.com/THE-MALT-LAB/COPRA
format Preprint
id arxiv_https___arxiv_org_abs_2605_15325
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle COPRA: Conditional Parameter Adaptation with Reinforcement Learning for Video Anomaly Detection
Jacob, Darryl Cherian
Liu, Xinyu
Wang, Kai
He, Pan
Computer Vision and Pattern Recognition
Vision-language models (VLMs) have shown strong performance in video anomaly detection (VAD) while providing interpretable predictions. However, existing VLM-based VAD methods suffer from a fundamental mismatch between training and inference in both data distribution and model configuration. First, most approaches rely on static post-training adaptation, limiting generalization under distribution shifts such as unseen environments or anomaly types. Second, they train VLMs on sparse frames from long videos, but perform inference on densely sampled short segments, creating inconsistencies between training and testing. To address these limitations, we propose COPRA, a conditional parameter adaptation framework for VLM-based VAD. Instead of fixed prompts or shared parameter updates, COPRA generates input-specific parameter updates to dynamically adapt a frozen VLM for each video segment during both training and inference. Experiments show strong performance on standard VAD benchmarks, consistently outperforming static baselines in both in-domain and cross-domain settings. Moreover, COPRA generalizes beyond VAD to unseen tasks such as multiple-choice Video Question Answering and Dense Captioning. These results highlight COPRA as an effective weight-space generation framework for scalable, adaptive, and context-aware video understanding. The code will be released at https://github.com/THE-MALT-LAB/COPRA
title COPRA: Conditional Parameter Adaptation with Reinforcement Learning for Video Anomaly Detection
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.15325