A Novel Spatial Mandibular Motion-Capture System Based on Planar Fiducial Markers

Motion-capture systems are important tools for several industrial and clinical applications. Although commercial optical motion-capture systems are available, their setup are often bulky, time consuming, and expensive, and require access to specialized laboratories. Several attempts have been made to introduce an alternative low-cost simple motion-capture system, though the performance has not been satisfactory addressed. In this paper, a compact, portable, low-cost, and simple planar-fiducial-marker-based motion-capture system (PFMS) is developed. The system comprises of one or two generic webcams for planar or spatial mandibular motion capturing, a tripod, planar markers printed on paper, and a computer for processing the real-time tracking of the markers. Sensor fusion of measurements from the two webcams in the PFMS results in accurate data for spatial mandibular motion capturing. The ability of the PFMS to record both planar and spatial motions is examined through capturing the complex 3-D movements of the incisal point of a human subject simultaneously by both the PFMS and a commercial research oriented optical motion-capture system. Least products regression and normalized root-mean-square error were used to compare the recordings by the two systems. The statistical analyses indicate a similar order of precision in the results obtained from the two systems, even though the PFMS is significantly cheaper and easier setup compared to the commercial 3-D motion-capture system.