Face orientation can often indicate users’ intended interaction target. In this paper, we propose FaceOri, a novel face tracking technique based on acoustic ranging using earphones. FaceOri can leverage the speaker on a commodity device to emit an ultrasonic chirp, which is picked up by the set of microphones on the user’s earphone, and then processed to calculate the distance from each microphone to the device. These measurements are used to derive the user’s face orientation and distance with respect to the device. We conduct a ground truth comparison and user study to evaluate FaceOri’s performance. The results show that the system can determine whether the user orients to the device at a 93.5% accuracy within a 1.5 meters range. Furthermore, FaceOri can continuously track user’s head orientation with a median absolute error of 10.9 mm in the distance, 3.7° in yaw, and 5.8° in pitch. FaceOri can allow for convenient hands-free control of devices and produce more intelligent context-aware interactions.

Debugging printed circuit boards (PCBs) can be a time-consuming process, requiring frequent context switching between PCB design files (schematic and layout) and the physical PCB. To assist electrical engineers in debugging PCBs, we present ARDW, an augmented reality workbench consisting of a monitor interface featuring PCB design files, a projector-augmented workspace for PCBs, tracked test probes for selection and measurement, and a connected test instrument. The system supports common debugging workflows for augmented visualization on the physical PCB as well as augmented interaction with the tracked probes. We quantitatively and qualitatively evaluate the system with 10 electrical engineers from industry and academia, finding that ARDW speeds up board navigation and provides engineers with greater confidence in debugging. We discuss practical design considerations and paths for improvement to future systems. A video demo of the system may be accessed here: https://youtu.be/RbENbf5WIfc .

We introduce RotoWrist, an infrared (IR) light based solution for continuously and reliably tracking 2-degree-of-freedom (DoF) relative angle of the wrist with respect to the forearm using a wristband. The tracking system consists of eight time-of-flight (ToF) IR light modules distributed around a wristband. We developed a computationally simple tracking approach to reconstruct the orientation of the wrist without any runtime training, ensuring user independence. An evaluation study demonstrated that RotoWrist achieves a cross-user median tracking error of 5.9° in flexion/extension and 6.8° in radial and ulnar deviation with no calibration required as measured with optical ground truth. We further demonstrate the performance of RotoWrist for a pointing task and compare it against ground truth tracking.

Input is a significant problem for wearable devices, particularly for head-mounted virtual and augmented reality systems. Contemporary AR/VR systems use in-air gestures or handheld controllers for interactivity. However, mid-air handwriting provides a natural, subtle, and easy-to-use way to input commands and text. In this demo, we propose and investigate ViFin, a new technique for input commands and text entry which tracks continuous micro finger-level writing with a commodity smartwatch through vibrations. Inspired by the recurrent neural aligner and transfer learning, ViFin recognizes continuous finger writing and works across different users and achieves an accuracy of 90% and 91% for recognizing numbers and letters, respectively. Finally, a real-time writing system with two specific applications using AR smartglasses are implemented.

The ability to track handheld controllers in 3D space is critical for interaction with head-mounted displays, such as those used in virtual and augmented reality systems. Today's systems commonly rely on dedicated infrastructure to track the controller or only provide inertial-based rotational tracking, which severely limits the user experience. Optical inside-out systems offer mobility but require line-of-sight and bulky tracking rings, which limit the ubiquity of these devices. In this work, we present Aura, an inside-out electromagnetic 6-DoF tracking system for handheld controllers. The tracking system consists of three coils embedded in a head-mounted display and a set of orthogonal receiver coils embedded in a handheld controller. We propose a novel closed-form and computationally simple tracking approach to reconstruct position and orientation in real time. Our handheld controller is small enough to fit in a pocket and consumes 45 mW of power, allowing it to operate for multiple days on a typical battery. An evaluation study demonstrates that Aura achieves a median tracking error of 5.5 mm and 0.8 degrees in 3D space within arm's reach.