High-fidelity facial and speech animation for VR HMDs

Significant challenges currently prohibit expressive interaction in virtual reality (VR). Occlusions introduced by head-mounted displays (HMDs) make existing facial tracking techniques intractable, and even state-of-the-art techniques used for real-time facial tracking in unconstrained environments fail to capture subtle details of the user's facial expressions that are essential for compelling speech animation. We introduce a novel system for HMD users to control a digital avatar in real-time while producing plausible speech animation and emotional expressions. Using a monocular camera attached to an HMD, we record multiple subjects performing various facial expressions and speaking several phonetically-balanced sentences. These images are used with artist-generated animation data corresponding to these sequences to train a convolutional neural network (CNN) to regress images of a user's mouth region to the parameters that control a digital avatar. To make training this system more tractable, we use audio-based alignment techniques to map images of multiple users making the same utterance to the corresponding animation parameters. We demonstrate that this approach is also feasible for tracking the expressions around the user's eye region with an internal infrared (IR) camera, thereby enabling full facial tracking. This system requires no user-specific calibration, uses easily obtainable consumer hardware, and produces high-quality animations of speech and emotional expressions. Finally, we demonstrate the quality of our system on a variety of subjects and evaluate its performance against state-of-the-art real-time facial tracking techniques.