Authentic Hand Avatar from a Phone Scan via Universal Hand Model
Authors: Gyeongsik Moon, Weipeng Xu, Rohan Joshi, Chenglei Wu, Takaaki Shiratori

The authentic 3D hand avatar with every identifiable information such as hand shapes and textures is necessary for immersive experiences in AR/VR. In this paper we present a universal hand model (UHM) which 1) can universally represent high-fidelity 3D hand meshes of arbitrary identities (IDs) and 2) can be adapted to each person with a short phone scan for the authentic hand avatar. For effective universal hand modeling we perform tracking and modeling at the same time while previous 3D hand models perform them separately. The conventional separate pipeline suffers from the accumulated errors from the tracking stage which cannot be recovered in the modeling stage. On the other hand ours does not suffer from the accumulated errors while having a much more concise overall pipeline. We additionally introduce a novel image matching loss function to address a skin sliding during the tracking and modeling while existing works have not focused on it much. Finally using learned priors from our UHM we effectively adapt our UHM to each person's short phone scan for the authentic hand avatar.