Fully vision-based calibration of a hand-eye robot

This article is concerned with calibrating an anthropomorphic two-armed robot equipped with a stereo-camera vision system, that is estimating the different geometric relationships involved in the model of the robot. The calibration procedure that is presented is fully vision-based: the relationships between each camera and the neck and between each arm and the neck are determined using visual measurements. The online calculation of all the relationships involved in the model of the robot is obtained with satisfactory precision and, above all, without expensive calibration mechanisms. For this purpose, two new main algorithms have been developed. The first one implements a non-linear optimization method using quaternions for camera calibration from 2D to 3D point or line correspondences. The second one implements a real-time camera pose estimation method based on the iterative use of a paraperspective camera model.