Improving the feasibility of ultrasonic hand tracking wearables

Wearable devices for activity tracking and gesture recognition have expanded rapidly in recent years. One technique that has shown great potential for this is ultrasonic imaging [10][4]. This technique has been shown to have advantages over other techniques in accuracy, surface area, placement and importantly, continuous finger angle estimations. However, ultrasonic imaging suffers from a couple of issues: First and foremost, the propagation of ultrasound into flesh suffers greatly without a suitable coupling medium; Secondly, the complexity of the driving circuitry for medical grade imaging currently renders a wearable version of this infeasible. This paper aims to address these two problems by finding a rigid coupling medium that lasts for significantly longer periods of time; and devising a new sensor configuration to reduce the device complexity, while still retaining the benefits of the technique. Furthermore, a comparison between high and low frequency systems reveal that different devices can be created with this technique for better resolution or convenience respectively.