Invariant Contamination Ratio (ICR)

A Fisher-information-based metric that decomposes a diffusion model's noise-level-conditioned features into an 'invariant' component (signal that should be constant across augmentations/noise realizations of the same underlying image) and a 'residual' component, then quantifies how much residual variation contaminates the invariant signal — unifying diagnosis of classification-optimal noise level, generative quality, and memorization onset in one measurement.