72.b Documentation with motion capture

Modern tracking technology for full body tracking, also referred to as motion capturing, can be used as an alternative or a complementary method to video recordings (see also Chapter 72.a on documenting with data gloves for a discussion). It offers a high precision of position and orientation information regarding specific points of reference, which can be chosen by the experimenter. Motion tracking can be used to collect movement trajectories, posture data, speed profiles and other performance indices. Disadvantages are: the employment of obtrusive technology that has to be applied to the body of the target, such as reflective markers used by optical tracking systems; data which describes rather the postures and movements of a stick-like figure than that of a body with certain masses – therefor motion capturing should almost always go together with video recordings; and last but not least the costs of the installation. The following text provides a short introduction into the state of the art of tracking technology that is available for the use in laboratories. While there are some companies that offer high-quality motion capturing services for the film and gaming industries, making use of their services is probably beyond scope of any modest research project. The following presentation is therefore focused on the technology that can be found in the research laboratories at the present time.