Skeleton Extraction for Articulated Objects with the Spherical Unwrapping Profiles

Embedding unified skeletons into unregistered scans is fundamental to finding correspondences, depicting motions, and capturing underlying structures among the articulated objects in the same category. Some existing approaches rely on laborious registration to adapt a predefined LBS model to each input, while others require the input to be set to a canonical pose, e.g. T-pose or A-pose. However, their effectiveness is always influenced by the water-tightness, face topology, and vertex density of the input mesh. At the core of our approach lies a novel unwrapping method, named SUPPLE  (Spherical UnwraPping ProfiLEs), which maps a surface into image planes independent of mesh topologies. Based on this lower-dimensional representation, a learning-based framework is further designed to localize and connect skeletal joints with fully convolutional architectures. Experiments demonstrate that our framework yields reliable skeleton extractions across a broad range of articulated categories, from raw scans to online CADs.