COFT-AD: COntrastive Fine-Tuning for Few-Shot Anomaly Detection

Fuente: arXiv
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Main Authors: Liao, Jingyi, Xu, Xun, Nguyen, Manh Cuong, Goodge, Adam, Foo, Chuan Sheng
Format: Preprint
Published: 2024
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author Liao, Jingyi
Xu, Xun
Nguyen, Manh Cuong
Goodge, Adam
Foo, Chuan Sheng
author_facet Liao, Jingyi
Xu, Xun
Nguyen, Manh Cuong
Goodge, Adam
Foo, Chuan Sheng
contents Existing approaches towards anomaly detection~(AD) often rely on a substantial amount of anomaly-free data to train representation and density models. However, large anomaly-free datasets may not always be available before the inference stage; in which case an anomaly detection model must be trained with only a handful of normal samples, a.k.a. few-shot anomaly detection (FSAD). In this paper, we propose a novel methodology to address the challenge of FSAD which incorporates two important techniques. Firstly, we employ a model pre-trained on a large source dataset to initialize model weights. Secondly, to ameliorate the covariate shift between source and target domains, we adopt contrastive training to fine-tune on the few-shot target domain data. To learn suitable representations for the downstream AD task, we additionally incorporate cross-instance positive pairs to encourage a tight cluster of the normal samples, and negative pairs for better separation between normal and synthesized negative samples. We evaluate few-shot anomaly detection on on 3 controlled AD tasks and 4 real-world AD tasks to demonstrate the effectiveness of the proposed method.
format Preprint
id arxiv_https___arxiv_org_abs_2402_18998
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle COFT-AD: COntrastive Fine-Tuning for Few-Shot Anomaly Detection
Liao, Jingyi
Xu, Xun
Nguyen, Manh Cuong
Goodge, Adam
Foo, Chuan Sheng
Computer Vision and Pattern Recognition
Existing approaches towards anomaly detection~(AD) often rely on a substantial amount of anomaly-free data to train representation and density models. However, large anomaly-free datasets may not always be available before the inference stage; in which case an anomaly detection model must be trained with only a handful of normal samples, a.k.a. few-shot anomaly detection (FSAD). In this paper, we propose a novel methodology to address the challenge of FSAD which incorporates two important techniques. Firstly, we employ a model pre-trained on a large source dataset to initialize model weights. Secondly, to ameliorate the covariate shift between source and target domains, we adopt contrastive training to fine-tune on the few-shot target domain data. To learn suitable representations for the downstream AD task, we additionally incorporate cross-instance positive pairs to encourage a tight cluster of the normal samples, and negative pairs for better separation between normal and synthesized negative samples. We evaluate few-shot anomaly detection on on 3 controlled AD tasks and 4 real-world AD tasks to demonstrate the effectiveness of the proposed method.
title COFT-AD: COntrastive Fine-Tuning for Few-Shot Anomaly Detection
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2402.18998