GAN-Based Single-Stage Defense for Traffic Sign Classification Under Adversarial Patch Attack

Computer Vision plays a critical role in ensuring the safe navigation of autonomous vehicles (AVs). An AV perception module is responsible for capturing and interpreting the surrounding environment to facilitate safe navigation. This module enables AVs to recognize traffic signs, traffic lights, and various road users. However, the perception module is vulnerable to adversarial attacks, which can compromise their accuracy and reliability. One such attack is the adversarial patch attack (APA), a physical attack in which an adversary strategically places a specially crafted sticker on an object to deceive object classifiers. In APA, an adversarial patch is positioned on a target object, leading the classifier to misidentify it. Such an APA can cause AVs to misclassify traffic signs, leading to catastrophic incidents. To enhance the security of an AV perception system against APAs, this study develops a Generative Adversarial Network (GAN)-based single-stage defense strategy for traffic sign classification. This approach is tailored to defend against APAs on different classes of traffic signs without prior knowledge of a patch's design. This study found this approach to be effective against patches of varying sizes. Our experimental analysis demonstrates that the defense strategy presented in this paper improves the classifier's accuracy under APA conditions by up to 80.8% and enhances overall classification accuracy for all the traffic signs considered in this study by 58%, compared to a classifier without any defense mechanism. Our defense strategy is model-agnostic, making it applicable to any traffic sign classifier, regardless of the underlying classification model.