ProGIP: Protecting Gradient-Based Input Perturbation Approaches for OOD Detection from Soft Errors

Undetected out-of-distribution (OOD) inputs pose a significant threat to the reliability of deep learning models, as they may lead to unexpected behaviors during inference. Several studies have proposed effective OOD input detection methods. However, soft errors—another significant threat to reliability—can impact both the classification results of neural network models and the ID/OOD detections of OOD detection methods. To provide a resilient OOD detection solution against soft errors, we analyze the effect of soft errors on neural network models with gradient-based input perturbation (GIP) approaches, which are representative methods for OOD detection. Building on our analysis, we propose ProGIP, which incorporates two software-level range-based fault detectors to protect all execution phases of GIP approaches, including two forward passes and one backward pass. Because it is purely software‑based and adds just two scalar comparisons, ProGIP is readily deployable even on resource‑constrained embedded platforms. Our ProGIP solution enables GIP approaches to distinguish between ID, OOD, and fault-affected inferences, detecting 97.7% of critical faults with a negligible runtime overhead of only 0.84%. Experimental results with 2.4 million fault injections across various neural networks and OOD detection methods demonstrate ProGIP’s effectiveness in ensuring comprehensive reliability against non-malicious threats.