Information-Theoretic Point Cloud Defense: Harnessing Conditional Mutual Information Against Adversarial Attacks
摘要
With the growing prominence of point cloud recognition, ensuring robustness against natural degradations and adversarial perturbations remains a critical challenge. Existing methods often fall short in effectively addressing these issues. In this work, we propose PointCMI, a novel adversarial training framework that leverages conditional mutual information (CMI) to achieve robust point cloud recognition. Specifically, we introduce a two-step strategy: (1) extracting class-specific feature centers from a clean model, and (2) constraining the perturbed outputs to remain close to these centers during adversarial training. By using CMI as a principled metric, PointCMI explicitly captures the class-wise complexity of clean and adversarial point clouds. This leads to a novel CMI minimization objective that drives both robustness and accuracy. Extensive experiments on ModelNet40 and ShapeNetPart demonstrate that PointCMI significantly outperforms existing defenses, setting a new benchmark in robust point cloud recognition.