Ensembled Cold-Diffusion Restorations for Unsupervised Anomaly Detection
<|reference_start|>Ensembled Cold-Diffusion Restorations for Unsupervised Anomaly Detection: Unsupervised Anomaly Detection (UAD) methods aim to identify anomalies in test samples comparing them with a normative distribution learned from a dataset known to be anomaly-free. Approaches based on generative models offer interpretability by generating anomaly-free versions of test images, but are typically unable to identify subtle anomalies. Alternatively, approaches using feature modelling or self-supervised methods, such as the ones relying on synthetically generated anomalies, do not provide out-of-the-box interpretability. In this work, we present a novel method that combines the strengths of both strategies: a generative cold-diffusion pipeline (i.e., a diffusion-like pipeline which uses corruptions not based on noise) that is trained with the objective of turning synthetically-corrupted images back to their normal, original appearance. To support our pipeline we introduce a novel synthetic anomaly generation procedure, called DAG, and a novel anomaly score which ensembles restorations conditioned with different degrees of abnormality. Our method surpasses the prior state-of-the art for unsupervised anomaly detection in three different Brain MRI datasets.<|reference_end|>
@article{marimont2024ensembled,
    title={Ensembled Cold-Diffusion Restorations for Unsupervised Anomaly Detection},
    author={Sergio Naval Marimont, Vasilis Siomos, Matthew Baugh, Christos
  Tzelepis, Bernhard Kainz, Giacomo Tarroni},
    journal={arXiv preprint arXiv:2407.06635},
    year={2024},
    archivePrefix={arXiv},
    eprint={2407.06635},
    primaryClass={cs.CV stat.ML}
}