VisualAD: Language-Free Zero-Shot Anomaly Detection via Vision Transformer

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Hou, Yanning, Li, Peiyuan, Liu, Zirui, Wang, Yitong, Ruan, Yanran, Qiu, Jianfeng, Xu, Ke
Natura: Preprint
Pubblicazione: 2026
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866915845713690624
author Hou, Yanning
Li, Peiyuan
Liu, Zirui
Wang, Yitong
Ruan, Yanran
Qiu, Jianfeng
Xu, Ke
author_facet Hou, Yanning
Li, Peiyuan
Liu, Zirui
Wang, Yitong
Ruan, Yanran
Qiu, Jianfeng
Xu, Ke
contents Zero-shot anomaly detection (ZSAD) requires detecting and localizing anomalies without access to target-class anomaly samples. Mainstream methods rely on vision-language models (VLMs) such as CLIP: they build hand-crafted or learned prompt sets for normal and abnormal semantics, then compute image-text similarities for open-set discrimination. While effective, this paradigm depends on a text encoder and cross-modal alignment, which can lead to training instability and parameter redundancy. This work revisits the necessity of the text branch in ZSAD and presents VisualAD, a purely visual framework built on Vision Transformers. We introduce two learnable tokens within a frozen backbone to directly encode normality and abnormality. Through multi-layer self-attention, these tokens interact with patch tokens, gradually acquiring high-level notions of normality and anomaly while guiding patches to highlight anomaly-related cues. Additionally, we incorporate a Spatial-Aware Cross-Attention (SCA) module and a lightweight Self-Alignment Function (SAF): SCA injects fine-grained spatial information into the tokens, and SAF recalibrates patch features before anomaly scoring. VisualAD achieves state-of-the-art performance on 13 zero-shot anomaly detection benchmarks spanning industrial and medical domains, and adapts seamlessly to pretrained vision backbones such as the CLIP image encoder and DINOv2. Code: https://github.com/7HHHHH/VisualAD
format Preprint
id arxiv_https___arxiv_org_abs_2603_07952
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle VisualAD: Language-Free Zero-Shot Anomaly Detection via Vision Transformer
Hou, Yanning
Li, Peiyuan
Liu, Zirui
Wang, Yitong
Ruan, Yanran
Qiu, Jianfeng
Xu, Ke
Computer Vision and Pattern Recognition
Zero-shot anomaly detection (ZSAD) requires detecting and localizing anomalies without access to target-class anomaly samples. Mainstream methods rely on vision-language models (VLMs) such as CLIP: they build hand-crafted or learned prompt sets for normal and abnormal semantics, then compute image-text similarities for open-set discrimination. While effective, this paradigm depends on a text encoder and cross-modal alignment, which can lead to training instability and parameter redundancy. This work revisits the necessity of the text branch in ZSAD and presents VisualAD, a purely visual framework built on Vision Transformers. We introduce two learnable tokens within a frozen backbone to directly encode normality and abnormality. Through multi-layer self-attention, these tokens interact with patch tokens, gradually acquiring high-level notions of normality and anomaly while guiding patches to highlight anomaly-related cues. Additionally, we incorporate a Spatial-Aware Cross-Attention (SCA) module and a lightweight Self-Alignment Function (SAF): SCA injects fine-grained spatial information into the tokens, and SAF recalibrates patch features before anomaly scoring. VisualAD achieves state-of-the-art performance on 13 zero-shot anomaly detection benchmarks spanning industrial and medical domains, and adapts seamlessly to pretrained vision backbones such as the CLIP image encoder and DINOv2. Code: https://github.com/7HHHHH/VisualAD
title VisualAD: Language-Free Zero-Shot Anomaly Detection via Vision Transformer
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2603.07952