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Bibliographic Details
Main Authors: Sivaprasad, Sarath, Fritz, Mario
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2310.00797
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author Sivaprasad, Sarath
Fritz, Mario
author_facet Sivaprasad, Sarath
Fritz, Mario
contents Anomaly Detection (AD) is a critical task that involves identifying observations that do not conform to a learned model of normality. Prior work in deep AD is predominantly based on a familiarity hypothesis, where familiar features serve as the reference in a pre-trained embedding space. While this strategy has proven highly successful, it turns out that it causes consistent false negatives when anomalies consist of truly novel features that are not well captured by the pre-trained encoding. We propose a novel approach to AD using explainability to capture such novel features as unexplained observations in the input space. We achieve strong performance across a wide range of anomaly benchmarks by combining familiarity and novelty in a hybrid approach. Our approach establishes a new state-of-the-art across multiple benchmarks, handling diverse anomaly types while eliminating the need for expensive background models and dense matching. In particular, we show that by taking account of novel features, we reduce false negative anomalies by up to 40% on challenging benchmarks compared to the state-of-the-art. Our method gives visually inspectable explanations for pixel-level anomalies.
format Preprint
id arxiv_https___arxiv_org_abs_2310_00797
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Don't Miss Out on Novelty: Importance of Novel Features for Deep Anomaly Detection
Sivaprasad, Sarath
Fritz, Mario
Machine Learning
Anomaly Detection (AD) is a critical task that involves identifying observations that do not conform to a learned model of normality. Prior work in deep AD is predominantly based on a familiarity hypothesis, where familiar features serve as the reference in a pre-trained embedding space. While this strategy has proven highly successful, it turns out that it causes consistent false negatives when anomalies consist of truly novel features that are not well captured by the pre-trained encoding. We propose a novel approach to AD using explainability to capture such novel features as unexplained observations in the input space. We achieve strong performance across a wide range of anomaly benchmarks by combining familiarity and novelty in a hybrid approach. Our approach establishes a new state-of-the-art across multiple benchmarks, handling diverse anomaly types while eliminating the need for expensive background models and dense matching. In particular, we show that by taking account of novel features, we reduce false negative anomalies by up to 40% on challenging benchmarks compared to the state-of-the-art. Our method gives visually inspectable explanations for pixel-level anomalies.
title Don't Miss Out on Novelty: Importance of Novel Features for Deep Anomaly Detection
topic Machine Learning
url https://arxiv.org/abs/2310.00797