Polarization Wavefront Lidar: Learning Large Scene Reconstruction from Polarized Wavefronts
Authors: Dominik Scheuble, Chenyang Lei, Seung-Hwan Baek, Mario Bijelic, Felix Heide

Lidar has become a cornerstone sensing modality for 3D vision especially for large outdoor scenarios and autonomous driving. Conventional lidar sensors are capable of providing centimeter-accurate distance information by emitting laser pulses into a scene and measuring the time-of-flight (ToF) of the reflection. However the polarization of the received light that depends on the surface orientation and material properties is usually not considered. As such the polarization modality has the potential to improve scene reconstruction beyond distance measurements. In this work we introduce a novel long-range polarization wavefront lidar sensor (PolLidar) that modulates the polarization of the emitted and received light. Departing from conventional lidar sensors PolLidar allows access to the raw time-resolved polarimetric wavefronts. We leverage polarimetric wavefronts to estimate normals distance and material properties in outdoor scenarios with a novel learned reconstruction method. To train and evaluate the method we introduce a simulated and real-world long-range dataset with paired raw lidar data ground truth distance and normal maps. We find that the proposed method improves normal and distance reconstruction by 53% mean angular error and 41% mean absolute error compared to existing shape-from-polarization (SfP) and ToF methods. Code and data are open-sourced here.