Marker-based motion tracking using Microsoft Kinect

Abstract

Abstract Motion capture systems are used to quantify kinematics of a motion in various fields of research. Despite high accuracy, commercial systems are expensive and complicated to use. The Microsoft Kinect has been used as an inexpensive markerless motion capture sensor but it has shown imprecision in measuring delicate motions. To address these limitations, we developed a marker-based motion capture system using the Kinect version 2 sensor. Joint use of the Kinect IR camera as a pinhole camera model and its depth data was introduced in order to calculate the 3-dimensional coordinates of retroreflective markers. The proposed method enabled us to capture joint angles of a human-like ankle flexion/extension motion performed by an HRP-2 humanoid using Kinect version 2 which is known to be a challenging task for the Kinect. The humanoid motion data was used as ground-truth to validate the accuracy of the novel motion capture system. The results pave the way for a breakthrough affordable motion capture system used in both robotics and clinical applications.