This paper tightens the evaluation of diffusion-based OOD detectors by controlling for backbone choice and test-time budget, then proposes sparse internal feature snapshots as a fairer detector family. It matters most as a methodology paper: the main contribution is cleaner comparison, not a new foundation model.
arXiv:2605.11014v1 Announce Type: new Abstract: Fair comparison between diffusion-based OOD detectors is challenging, as conclusions can vary with backbone choice, corruption parameterization, and test-time budget. We address this issue through a Mutualized Backbone-Equated (MBE) protocol that aligns canonical corruption levels and logical test-time cost across diffusion backbones. Within this setting, we introduce Canonical Feature Snapshots (CFS), a family of detectors that probes a frozen…