Unsupervised Patch-GAN with Targeted Patch Ranking for Fine-Grained Novelty Detection in Medical Imaging

Fuente: arXiv
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Autores principales: Chen, Jingkun, Yang, Guang, Zhang, Xiao, Peng, Jingchao, Zhang, Tianlu, Zhang, Jianguo, Han, Jungong, Grau, Vicente
Formato: Preprint
Publicado: 2025
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author Chen, Jingkun
Yang, Guang
Zhang, Xiao
Peng, Jingchao
Zhang, Tianlu
Zhang, Jianguo
Han, Jungong
Grau, Vicente
author_facet Chen, Jingkun
Yang, Guang
Zhang, Xiao
Peng, Jingchao
Zhang, Tianlu
Zhang, Jianguo
Han, Jungong
Grau, Vicente
contents Detecting novel anomalies in medical imaging is challenging due to the limited availability of labeled data for rare abnormalities, which often display high variability and subtlety. This challenge is further compounded when small abnormal regions are embedded within larger normal areas, as whole-image predictions frequently overlook these subtle deviations. To address these issues, we propose an unsupervised Patch-GAN framework designed to detect and localize anomalies by capturing both local detail and global structure. Our framework first reconstructs masked images to learn fine-grained, normal-specific features, allowing for enhanced sensitivity to minor deviations from normality. By dividing these reconstructed images into patches and assessing the authenticity of each patch, our approach identifies anomalies at a more granular level, overcoming the limitations of whole-image evaluation. Additionally, a patch-ranking mechanism prioritizes regions with higher abnormal scores, reinforcing the alignment between local patch discrepancies and the global image context. Experimental results on the ISIC 2016 skin lesion and BraTS 2019 brain tumor datasets validate our framework's effectiveness, achieving AUCs of 95.79% and 96.05%, respectively, and outperforming three state-of-the-art baselines.
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publishDate 2025
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spellingShingle Unsupervised Patch-GAN with Targeted Patch Ranking for Fine-Grained Novelty Detection in Medical Imaging
Chen, Jingkun
Yang, Guang
Zhang, Xiao
Peng, Jingchao
Zhang, Tianlu
Zhang, Jianguo
Han, Jungong
Grau, Vicente
Computer Vision and Pattern Recognition
Image and Video Processing
Detecting novel anomalies in medical imaging is challenging due to the limited availability of labeled data for rare abnormalities, which often display high variability and subtlety. This challenge is further compounded when small abnormal regions are embedded within larger normal areas, as whole-image predictions frequently overlook these subtle deviations. To address these issues, we propose an unsupervised Patch-GAN framework designed to detect and localize anomalies by capturing both local detail and global structure. Our framework first reconstructs masked images to learn fine-grained, normal-specific features, allowing for enhanced sensitivity to minor deviations from normality. By dividing these reconstructed images into patches and assessing the authenticity of each patch, our approach identifies anomalies at a more granular level, overcoming the limitations of whole-image evaluation. Additionally, a patch-ranking mechanism prioritizes regions with higher abnormal scores, reinforcing the alignment between local patch discrepancies and the global image context. Experimental results on the ISIC 2016 skin lesion and BraTS 2019 brain tumor datasets validate our framework's effectiveness, achieving AUCs of 95.79% and 96.05%, respectively, and outperforming three state-of-the-art baselines.
title Unsupervised Patch-GAN with Targeted Patch Ranking for Fine-Grained Novelty Detection in Medical Imaging
topic Computer Vision and Pattern Recognition
Image and Video Processing
url https://arxiv.org/abs/2501.17906