A training‑free agentic framework · ground → track → reason
Figure 1. A toothpaste tube undergoes pressing and deformation before a subtle leakage emerges. Traditional VAD predicts a binary label and VLM prompting misses the event; O‑VAD tracks object‑wise state changes and produces an open‑ended anomaly report with grounded frames and causal analysis.
01 / Abstract
Industrial Video Anomaly Detection (IVAD) aims to identify anomalous objects and events in an industrial process, which is crucial for modern manufacturing and quality‑control systems. Existing VLM‑based anomaly‑reasoning methods can detect open‑ended anomalies in general domains, but their performance declines in industrial settings characterized by intricate object transformations, strict physics, and procedural constraints.
To tackle the complexity of such interaction‑intensive detection, we introduce O‑VAD, a training‑free agentic framework free of domain‑specific knowledge that emphasizes object state evolution. It tracks the spatial‑temporal dynamics and underlying transformations of detected objects over time, then reasons over the object‑wise temporal state trajectories to identify abnormal objects in grounded frames — overcoming prior approaches that rely on retraining on normal clips or injecting domain knowledge at test time.
Extensive experiments on three IVAD datasets show O‑VAD outperforms frontier VLMs, agentic frameworks, and traditional VAD methods fine‑tuned on the respective datasets, while providing interpretable reports over anomaly processes and types.
Training‑free — no fine‑tuning, no domain knowledge, no predefined taxonomy.
Best video‑level AUROC on every benchmark
02 / Method
Given an industrial video, O‑VAD produces a structured anomaly report — type, severity, affected object, temporal localization, and a natural‑language causal explanation — without any domain‑specific knowledge, predefined taxonomy, or training data. It runs in three agentic stages.
Sample frames spanning the video, query a VLM for a structured object inventory (name, material, initial state), then segment every object with SAM3 to produce initial masks and metadata.
Build spatiotemporal tubelets with CropFormer entity segmentation and SAM2 propagation. Recover tracks lost through transformations using spatial‑proximity and CLIP semantic‑consistency priors, then query the VLM for open‑ended state‑change events — type, cause, severity, per object.
A cascaded six‑step chain‑of‑thought reasons over the accumulated state trajectories, separating expected process actions from failure outcomes.
03 / Quantitative results
We foreground the metrics that matter for open-ended IVAD — detection AUROC (video and frame level) and anomaly-type description quality — and drop Acc/P/R/F1. O‑VAD posts the best video-level AUROC on all three datasets and the most faithful type descriptions, then leads or ties across most Phys-AD and IPAD categories.
Higher is better; per row the best is boxed and the 2nd-best shaded; O‑VAD shown in accent. Phys-AD has no frame-level labels; LiquidAD and IPAD carry no free-form type score. † trained ∗ training-free.
04 / Qualitative results
We compare O‑VAD against GPT‑5 prompted with the same six‑step chain‑of‑thought but without object grounding or state tracking. Lacking object‑wise evidence, GPT‑5 defaults to “no anomaly”; O‑VAD localizes the object, frame range, severity, and root cause.
4.1 / CASE COMPARISONS
4.2 / Failure cases
Without predefined expert knowledge, O‑VAD misses two families of anomaly: specification‑dependent ones whose ground truth is a quantitative threshold invisible to inspection, and perception‑ambiguous ones whose defining evidence never appears in the frame. Four representative cases:
Challenging categories. O‑VAD’s weakest Phys‑AD AUROC lands on Caster Wheel (0.301), Zipper (0.388), Button (0.393), and Slide (0.414) — subtle rotational resistance, small localized transitions missed at the default sampling interval, and alignment hard to judge from cropped views. These motivate adaptive temporal sampling and multi‑scale spatial reasoning.
4.3 / Human evaluation & LLM-as-judge
Beyond automated metrics, five domain experts rated report quality on 10 Phys-AD videos (5-point Likert), and a GPT-4o judge mirroring the same questionnaire scaled the study to the full test set. O‑VAD leads every dimension of both, against direct prompting (Qwen3-VL-32B) and the agentic URF-ZS-HVAA.
Mean ratings (1–5, higher better) unless marked %; O‑VAD in accent with a fill bar; “–” = URF-ZS-HVAA near-floor value not itemized in the paper. Q3 and Q5 human per-method scores are reported only as part-level aggregates.
05 / Ablations
Removing one module at a time on four representative Phys‑AD subsets isolates each contribution.
Removing it collapses precision, recall, and F1 to zero on three of four subsets — the system predicts everything “normal.”
Scene semantics guide holistic anomalies; dropping captions costs up to 0.25 AUC on sticky‑roller and rubber‑band.
The six‑step chain lifts AUC by 0.04–0.09 over a generic “think step by step” prompt.
Multiplicative confidence gating sharpens borderline cases, adding up to 0.18 AUC on sticky roller.
Full model in bold; orange marks a drop from the full model. Removing state tracking additionally collapses F1 to 0.000 on three of four subsets.
06 / DEMO
A short overview of the ground → track → reason pipeline and representative anomaly reports.
Grounding → tracking on LiquidAD. Stage 1 assigns one mask per object — eight visually identical pipettes plus the trays. Stage 2 propagates each into a stable tubelet, holding identity through partial occlusion by the dispensing head and during liquid transfer.
07 / Citation
@inproceedings{yuan2026ovad,
title = {O-VAD: Industrial Video Anomaly Detection
through Object-Centric Tracking and Reasoning},
author = {Yuan, Mei and Long, Qi and Wu, Qifeng and Li, Zhenyang and
Zhao, Yizhou and Wang, Lei and Liu, Yang and Xu, Min},
booktitle = {Proceedings of the European Conference on Computer Vision (ECCV)},
year = {2026}
}