Geometric Adversarial Attacks and Defenses on 3D Point Clouds

Deep neural networks are prone to adversarial examples that maliciously alter the network's outcome. Due to the increasing popularity of 3D sensors in safety-critical systems and the vast deployment of deep learning models for 3D point sets, there is a growing interest in adversarial attacks and defenses for such models. So far, the research has focused on the semantic level, namely, deep point cloud classifiers. However, point clouds are also widely used in a geometric-related form that includes encoding and reconstructing the geometry. In this work, we explore adversarial examples at a geometric level. That is, a small change to a clean source point cloud leads, after passing through an autoencoder model, to a shape from a different target class. On the defense side, we show that remnants of the attack's target shape are still present at the reconstructed output after applying the defense to the adversarial input. Our code is publicly available at https://github.com/itailang/geometric_adv.