Lip-Interact

We present Lip-Interact, an interaction technique that allows users to issue commands on their smartphone through silent speech. Lip-Interact repurposes the front camera to capture the user's mouth movements and recognize the issued commands with an end-to-end deep learning model. Our system supports 44 commands for accessing both system-level functionalities (launching apps, changing system settings, and handling pop-up windows) and application-level functionalities (integrated operations for two apps). We verify the feasibility of Lip-Interact with three user experiments: evaluating the recognition accuracy, comparing with touch on input efficiency, and comparing with voiced commands with regards to personal privacy and social norms. We demonstrate that Lip-Interact can help users access functionality efficiently in one step, enable one-handed input when the other hand is occupied, and assist touch to make interactions more fluent.