Detecting Backdoors in Object Detection via Pre-NMS Prediction Distribution Shift
Researchers have proposed a method called DistScan to detect backdoors in object detection models. A backdoor is a hidden trigger that causes the model to misbehave when present. Existing methods either rely on finding the trigger or exploiting specific architecture assumptions. However, these methods often fail to generalize to scene-level attacks where a single trigger affects all objects in the scene simultaneously. DistScan works by observing that backdoors shift a model'
Researchers have proposed a method called DistScan to detect backdoors in object detection models. A backdoor is a hidden trigger that causes the model to misbehave when present. Existing methods either rely on finding the trigger or exploiting specific architecture assumptions. However, these methods often fail to generalize to scene-level attacks where a single trigger affects all objects in the scene simultaneously. DistScan works by observing that backdoors shift a model's pre-NMS prediction class distribution away from its training frequencies. It aggregates intermediate predictions over a clean validation set and flags the model as backdoored if the resulting distribution deviates significantly from the training frequencies. The authors tested DistScan on several datasets and architectures, showing it outperforms existing methods by a significant margin.
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Why it matters: This matters to AI researchers because object detection models are often deployed in safety-critical applications where backdoors can have serious consequences. A reliable method for detecting backdoors is crucial for ensuring the trustworthiness of these models.
Source: https://arxiv.org/abs/2608.19088
This article was originally published at: https://arxiv.org/abs/2608.19088