arXiv:2608.00695cs.CV2026-08

通过频域差异检测异常,无需文本提示即可精准定位缺陷。

FreqAnchorAD: Language-Free Zero-Shot Anomaly Detection via Frequency-Deviation Anchoring

论文配图:FreqAnchorAD: Language-Free Zero-Shot Anomaly Detection via Frequency-Deviation Anchoring
图 1 · 摘自论文原文
  • 利用频域特征差异构建异常判断基准,避免空间细节混淆。
  • 在13个工业与医疗数据集上实现图像级与像素级最优表现。
  • 适合无标注数据的工业质检场景,尤其擅长捕捉细微纹理异常。

零样本异常检测(ZSAD)旨在未见目标领域中不依赖目标训练数据检测并定位缺陷区域。现有方法基于预训练视觉模型(如CLIP),通过文本提示或可学习视觉表示构建正常与异常参考,主要在空间特征空间进行判别,易将纹理、边界等微小变化误判为异常。然而,这些缺陷在空间上不明显,却会破坏局部纹理规律或边界连续性,引发多频带响应偏差。我们发现,局部缺陷在低、中、高频段均呈现相对于正常参考的频域偏移,表明异常证据并非仅由高频响应主导。为此,提出频域感知框架FreqAnchorAD,通过频率增强响应实现锚定式异常判别。其中,局部频域补偿模块(LFCM)增强中间块令牌的局部空间-频域线索;核心判别模块频域偏差锚定投影器(FDAP)沿源导出通道坐标组织增强响应,通过相对相似性度量异常证据;不对称锚定监督(AAS)稳定正常锚点对齐,同时保留多样异常模式。在13个工业与医疗基准上的实验表明,FreqAnchorAD在图像级异常识别和像素级缺陷定位上均达到当前最优性能。

原文摘要 · Abstract (English)

Zero-shot anomaly detection (ZSAD) aims to detect anomalies and localize defective regions in unseen target domains without target training data. Recent ZSAD methods build on pretrained vision models, particularly CLIP, and construct normal and anomaly references from textual prompts or learnable visual representations. These methods perform anomaly discrimination primarily in spatial feature spaces, where subtle changes in texture, boundaries, and local structures can be confused with normal appearance variations. Although inconspicuous spatially, such defects can disrupt local texture regularity or boundary continuity, inducing response deviations across frequency bands. However, existing ZSAD methods do not explicitly model these frequency-dependent characteristics. Our image-domain analysis reveals that local defects exhibit spatial-frequency deviations from normal references across low-, middle-, and high-frequency bands, indicating that anomaly evidence is not universally dominated by high-frequency responses. Motivated by this observation, we propose FreqAnchorAD, a frequency-aware framework that organizes frequency-enhanced responses for anchor-relative anomaly discrimination. Specifically, the Local Frequency Compensation Module (LFCM) enhances intermediate patch tokens with local spatial-frequency cues. The Frequency-Deviation Anchor Projector (FDAP), our core discrimination module, organizes enhanced responses along a source-derived channel coordinate and measures anomaly evidence through relative similarity to normal and anomaly anchors. Finally, Asymmetric Anchor Supervision (AAS) stabilizes normal-anchor alignment while preserving diverse anomaly patterns. Experiments on thirteen industrial and medical benchmarks show that FreqAnchorAD achieves state-of-the-art mean performance in image-level anomaly recognition and pixel-level defect localization.

异常检测频域分析零样本

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