SmartPTA: A Smartphone-Based Human Motion Evaluation System

This paper considers a human motion evaluation system (HMES) using two smartphones and a server. An HMES user wears retro-reflective markers on her 13 joints and follows a motion demonstrated by an expert. Two smartphones detect markers and transmit detected 2D marker positions to the server which reconstructs 3D motion of the user. The server performs a spatio-temporal alignment between the motion of the user and the motion demonstrated by an expert to evaluate the quality of the user's motion. The proposed system is applicable for physical therapy and sports education as an inexpensive alternative. We demonstrate that the 3D motion of the HMES user can be reconstructed reliably in real-time and successfully aligned with the reference motion of an expert, providing real-time feedback to the user.