Spatial Autoregressive Modeling of DINOv3 Embeddings for Unsupervised Anomaly Detection

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Main Authors: Erdil, Ertunc, Schulthess, Nico, Tombak, Guney, Konukoglu, Ender
Format: Preprint
Published: 2026
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author Erdil, Ertunc
Schulthess, Nico
Tombak, Guney
Konukoglu, Ender
author_facet Erdil, Ertunc
Schulthess, Nico
Tombak, Guney
Konukoglu, Ender
contents DINO models provide rich patch-level representations that have recently enabled strong performance in unsupervised anomaly detection (UAD). Most existing methods extract patch embeddings from ``normal'' images and model them independently, ignoring spatial and neighborhood relationships between patches. This implicitly assumes that self-attention and positional encodings sufficiently encode contextual information within each patch embedding. In addition, the normative distribution is often modeled as memory banks or prototype-based representations, which require storing large numbers of features and performing costly comparisons at inference time, leading to substantial memory and computational overhead. In this work, we address both limitations by proposing a simple and efficient framework that explicitly models spatial and contextual dependencies between patch embeddings using a 2D autoregressive (AR) model. Instead of storing embeddings or clustering prototypes, our approach learns a compact parametric model of the normative distribution via an AR convolutional neural network (CNN). At test time, anomaly detection reduces to a single forward pass through the network and enables fast and memory-efficient inference. We evaluate our method on the BMAD benchmark, which comprises three medical imaging datasets, and compare it against existing work including recent DINO-based methods. Experimental results demonstrate that explicitly modeling spatial dependencies achieves competitive anomaly detection performance while substantially reducing inference time and memory requirements. Code is available at the project page: https://eerdil.github.io/spatial-ar-dinov3-uad/.
format Preprint
id arxiv_https___arxiv_org_abs_2603_02974
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spatial Autoregressive Modeling of DINOv3 Embeddings for Unsupervised Anomaly Detection
Erdil, Ertunc
Schulthess, Nico
Tombak, Guney
Konukoglu, Ender
Computer Vision and Pattern Recognition
DINO models provide rich patch-level representations that have recently enabled strong performance in unsupervised anomaly detection (UAD). Most existing methods extract patch embeddings from ``normal'' images and model them independently, ignoring spatial and neighborhood relationships between patches. This implicitly assumes that self-attention and positional encodings sufficiently encode contextual information within each patch embedding. In addition, the normative distribution is often modeled as memory banks or prototype-based representations, which require storing large numbers of features and performing costly comparisons at inference time, leading to substantial memory and computational overhead. In this work, we address both limitations by proposing a simple and efficient framework that explicitly models spatial and contextual dependencies between patch embeddings using a 2D autoregressive (AR) model. Instead of storing embeddings or clustering prototypes, our approach learns a compact parametric model of the normative distribution via an AR convolutional neural network (CNN). At test time, anomaly detection reduces to a single forward pass through the network and enables fast and memory-efficient inference. We evaluate our method on the BMAD benchmark, which comprises three medical imaging datasets, and compare it against existing work including recent DINO-based methods. Experimental results demonstrate that explicitly modeling spatial dependencies achieves competitive anomaly detection performance while substantially reducing inference time and memory requirements. Code is available at the project page: https://eerdil.github.io/spatial-ar-dinov3-uad/.
title Spatial Autoregressive Modeling of DINOv3 Embeddings for Unsupervised Anomaly Detection
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2603.02974