Statistical Test for Diffusion-Based Anomaly Localization via Selective Inference

arXiv stat.ML / 4/28/2026

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Key Points

  • The paper targets image anomaly localization by using diffusion-based generative models to create normal-looking counterparts, while addressing reliability concerns tied to the generative model’s embedded uncertainty and bias.
  • It introduces a statistical framework grounded in selective inference that outputs p-values for detected anomalous regions.
  • The proposed p-values are intended to quantify false positive detection rates, offering a principled way to measure the significance and trustworthiness of localization results.
  • As a proof of concept, the authors apply the approach to anomaly localization using a diffusion model, demonstrating its effectiveness for both medical diagnosis and industrial inspection scenarios.
  • Results suggest the method can control the risk of false positives, supporting its suitability for high-stakes decision-making.

Abstract

Anomaly localization in images -- identifying regions that deviate from normal patterns -- is vital in applications such as medical diagnosis and industrial inspection. A recent trend is the use of image generation models in anomaly localization, where these models generate normal-looking counterparts of anomalous images, thereby allowing flexible and adaptive anomaly localization. However, these methods inherit the uncertainty and bias implicitly embedded in the employed generative model, raising concerns about the reliability. To address this, we propose a statistical framework based on selective inference to quantify the significance of detected anomalous regions. Our method provides p-values to assess the false positive detection rates, providing a principled measure of reliability. As a proof of concept, we consider anomaly localization using a diffusion model and its applications to medical diagnoses and industrial inspections. The results indicate that the proposed method effectively controls the risk of false positive detection, supporting its use in high-stakes decision-making tasks.