where T P is the true-positive rate and F N is the falsenegative rate calculated for a classifier based on each threshold value along the ROC. The strong separability of the stable and unstable cases is reflected in the insensitivity of the ROC to a specific choice of ∆⟨λ⟩. The optimal threshold, ∆⟨λ⟩ = 0.11, shows excellent accuracy of 97%. The accuracy is surprisingly invariant to ∆⟨σ 2 ⟩, meaning that structures with large angular distortions are still observed to be relatively stable.