System Design of Ultrasonic 2D Hand Gesture Trajectory Capture Using Variable Gain

This paper presents a technique for two dimensional (2D) hand gesture trajectory capture system which can be applied to the interaction of intelligent equipment. Firstly, the sensing principle and hardware are described. In the processing of gesture trajectory, an automatic calibration algorithm based on cross correlation operation is proposed to resolve the interference from environment; the dynamic threshold and variable gain methods are developed to extract distance and the finger positioning model is established basing on the geometric relation. Finally, we obtain the hand gesture trajectory with our hardware in real time and demonstrate the effectiveness of the system.