Gesture Recognition Method Based on Ultrasound Propagation in Body

We propose a method for gesture recognition that utilizes active acoustic sensing, which transmits acoustic signals to a target, and recognizes the target's state by analyzing the response. In this study, the user wore a contact speaker that transmitted ultrasonic sweep signals to the user's body and a contact microphone that detected the ultrasound propagated through the body. The propagation characteristics of the ultrasound changed depending on the user movements. We utilized these changes to recognize the user's gestures. The novel point of our method is that the user's gestures can be acquired not only from the apparent movement but also from the user's internal state, such as muscle activity, since ultrasound is transmitted to the user's internal body and body surface. We implemented a prototype device and investigated the performance of the proposed method in 21 contexts with 10 subjects. The evaluation results confirmed that the recognition accuracy was 91.6 % on average when we trained/tested using the same data set.