Polarization is a fundamental property of light that encodes abundant information regarding surface shape, material, illumination and viewing geometry. The computer vision community has witnessed a blossom of polarization-based vision applications, such as reflection removal, shape-from-polarization, transparent object segmentation and color constancy, partially due to the emergence of single-chip mono/color polarization sensors that make polarization data acquisition easier than ever. However, is polarization-based vision vulnerable to adversarial attacks? If so, is that possible to realize these adversarial attacks in the physical world, without being perceived by human eyes? In this paper, we warn the community of the vulnerability of polarization-based vision, which can be more serious than RGB-based vision. By adapting a commercial LCD projector, we achieve locally controllable polarizing projection, which is successfully utilized to fool state-of-the-art polarization-based vision algorithms for glass segmentation and color constancy. Compared with existing physical attacks on RGB-based vision, which always suffer from the trade-off between attack efficacy and eye conceivability, the adversarial attackers based on polarizing projection are contact-free and visually imperceptible, since naked human eyes can rarely perceive the difference of viciously manipulated polarizing light and ordinary illumination. This poses unprecedented risks on polarization-based vision, both in the monochromatic and trichromatic domain, for which due attentions should be paid and counter measures be considered.

翻译：偏振是光的基本属性，它编码了关于表面形状、材料、光照和观察几何的丰富信息。由于单芯片单色/彩色偏振传感器的出现使得偏振数据采集比以往更加容易，计算机视觉领域见证了基于偏振的视觉应用的蓬勃发展，例如反射去除、偏振形状重建、透明物体分割和颜色恒常性。然而，基于偏振的视觉是否容易受到对抗性攻击？如果是这样，是否有可能在物理世界中实现这些对抗性攻击，而不被人类眼睛察觉？在本文中，我们提醒学界注意基于偏振的视觉的脆弱性，其可能比基于RGB的视觉更为严重。通过改造商用LCD投影仪，我们实现了局部可控的偏振投影，并成功利用它来欺骗最先进的基于偏振的视觉算法，用于玻璃分割和颜色恒常性。与现有对基于RGB的视觉的物理攻击相比，这些攻击总是在攻击效果与肉眼可见性之间权衡，基于偏振投影的对抗性攻击是非接触式且视觉上不可察觉的，因为肉眼几乎无法感知恶意操纵的偏振光与普通光照之间的差异。这给基于偏振的视觉带来了前所未有的风险，无论是在单色域还是三色域，都应引起足够重视并考虑应对措施。