RF-Sauron: Enabling Contact-Free Interaction on Eyeglass Using Conformal RFID Tag

Smart eyeglasses are emerging as a new medium for human-computer interaction. Existing solutions typically rely on cameras or touchpads, raising privacy invasion concerns or requiring users to physically interact with the glass frames. Here, we present RF-Sauron, a novel mid-air gesture interaction system for eyeglasses, based on radio frequency identification (RFID). The design of our RF-Sauron system involves embedding a conformal RFID tag into the eyeglass frame, where the received signals change with user gestures. We optimize the radiation gain of the tag to avoid view blockage while preserving a long working range. To discriminate different gestures, we propose an adaptively weighted multichannel fusion network to extract their respective distinctive features. To allow efficient adaptation of the pretrained network to new users, we also introduce a novel diagonal dot-product attention in our contrastive learning framework to uncover the feature similarities of different users. The proposed RF-Sauron system was evaluated through extensive experiments, demonstrating an average recognition accuracy of 98.86% across 20 users and a cross-user accuracy of 98.75%.