A portable and low-cost 3D tracking system using four-point planar square calibration

A practical indoor tracking system should be accurate, affordable, portable and easy-to-use. However, most of the current tracking applications lack in at least one of these properties. To fill this gap, we present such a 3D tracking system. Built around two to four wireless Nintendo Wii Remotes, the system can simultaneously track up to four infrared LEDs carried by multiple users. The set up and calibration takes only a few minutes. A semiautomatic calibration method is used, where the user places the infrared LED marker sequentially on the four corners of a freely defined square in the tracking area. Within a cube with an edge length of 2.5 m, the system was found to be able to track both a static and a moving target with an accuracy of 3 cm. In addition to discussing the developed system, this paper presents computational methods for improving the positioning accuracy by altering the assumed optical centers of the Wii Remote cameras, which vary due to intrinsic differences in them.