We propose spatial polarization multiplexing (SPM) for joint sensing of shape and reflectance of a static or dynamic deformable object, which is also invisible to the naked eye. Past structured-light methods are limited to shape acquisition and cannot recover reflectance as they alter scene appearance. Our key idea is to spatially multiplex a polarization pattern to encode the incident ray and also densely sample the reflected light. We derive a quantized polarized light pattern that can be robustly and uniquely decoded from the reflected Angle of Linear Polarization (AoLP) values. It also enables single-shot disentanglement of polarimetric diffuse and specular reflections for accurate BRDF estimation. We achieve this spatial polarization multiplexing (SPM) with a constrained de Bruijn sequence. We validate this novel invisible single-shot shape and reflectance method with real static and dynamic objects. The results demonstrate the effectiveness of SPM for accurate shape and BRDF measurement which opens new avenues of application for 3D sensing thanks to its invisibility and ability to jointly recover the radiometric properties.

翻译：我们提出空间偏振复用（SPM）方法，用于联合感知静态或动态可变形物体的形状与反射率，同时该方法对肉眼不可见。以往的结构光方法局限于形状获取，且因改变场景外观而无法恢复反射率。我们的核心思想是通过空间复用偏振图案来编码入射光线，并密集采样反射光。我们推导出一种量化偏振光图案，能够从反射的线偏振角（AoLP）值中稳健且唯一地解码。该方法还能实现单次分离偏振漫反射与镜面反射，以进行精确的BRDF估计。我们利用约束德布鲁因序列实现了这种空间偏振复用（SPM）。我们通过真实静态与动态物体验证了这一新颖的不可见单次形状与反射率方法。结果表明，SPM在精确形状与BRDF测量方面具有高效性，其不可见特性及联合恢复辐射度属性的能力为三维传感开辟了新的应用途径。