Sparse Wearable Sonomyography Sensor-Based Proprioceptive Proportional Control Across Multiple Gestures

Sonomyography (SMG) is a noninvasive technique that uses ultrasound imaging to detect the dynamic activity of muscles. Wearable SMG systems have recently gained popularity due to their potential as human–computer interfaces for their superior performance compared with conventional methods. This article demonstrates real-time positional proportional control of multiple gestures using a multiplexed eight-channel wearable SMG system. The amplitude-mode ultrasound signals from the SMG system were utilized to detect muscle activity from the forearm of eight healthy individuals. The derived SMG signals were used to control the on-screen position of the cursor. A target achievement task was performed to analyze the performance of our SMG-based human–machine interface. Our wearable SMG system provided accurate, stable, and intuitive control in real time by achieving an average success rate greater than 80% with all gestures. Furthermore, the wearable SMG system’s abilities to detect volitional movement and decode movement kinematic information from SMG trajectories using standard performance metrics were evaluated. Our results provide insights to validate SMG as an intuitive human–machine interface.