I. Introduction
Due to the widespread of the low-cost RGBD sensors, the real time 3D human pose estimation is available on the commercial products, such as Microsoft Xbox using Kinect for human computer interaction (HCI) games [1], [2]. More potential applications have been studied in many research fields. For instance, Morato et al. developed a N-Kinect system to build an explicit model of the human body, which is used to detect an imminent collision between the robot and the human [3]. Pathirana et al. proposed a Kinect based bio-kinematic measurement system for rehabilitation and physiotherapy applications, i.e., monitoring of home-based prescribed exercise routines which can significantly reduce the need for patients to travel to regional centers [4]. Geiselhart et al. estimated the workers movements and interaction with digital object models using multi-depth camera system [5], such that a low cost camera setup to facilitate interaction with virtual environments for planning experts is possible.