Predicting Polarization Beyond Semantics for Wearable Robotics

Semantic perception is a key enabler in robotics, which supposes a very resourceful and efficient manner of applying vision information for upper-level navigation and manipulation tasks. Given the challenges on specular semantics such as water hazards, transparent glasses and metallic surfaces, polarization imaging has been explored to complement the RGB-based pixel-wise semantic segmentation because it reflects surface characteristics and provides additional attributes. However, polarimetric measurements generally entail prohibitively expensive cameras and highly accurate calibrations. Inspired by the representation power of Convolutional Neural Networks (CNNs), we propose to predict polarization information from monocular RGB images, precisely per-pixel polarization difference. The core of our approach is a cluster of efficient deep architectures building on factorized convolutions, hierarchical dilations and pyramid representations, aimed to produce both semantic and polarimetric estimations in real time. Comprehensive experiments demonstrate the qualified accuracy on a wearable exoskeleton humanoid robot.