The design and calibration of a 3D motion capture system for arthropods

In this paper we discuss the design and calibration of a motion capture system for small animal motion. In particular we are interested in reconstructing a moving 3D model of the Otago Fishing Spider (Dolomedes aquaticus) in order to analyse its gait and locomotion. The system consists of a high speed camera mounted above an arena surrounded by mirrors, giving five synchronised views of the animal´s motion. We discuss the calibration of this system, and show that we can predict the projection of 3D points to an accuracy of 0.15 pixels, which corresponds to a location error of 0.06 mm. We also present initial results on 3D reconstruction of the spider´s motion.