Extended-2D visual servoing

This paper presents a novel visual servoing approach, aimed at controlling the so-called extended-2D (EM) coordinates of the points constituting a tracked target. This approach does not require any pose reconstruction. Rather, the only informations required to build the E2D coordinates are the estimated depth distribution of the target points, and the estimated camera model. Several implementations of the controller are considered, which are inspired from conventional image based visual servoing from points. In spite of their simplicity, the proposed control laws exhibit remarkable stability robustness properties. A key issue is that only three configurations of undesired equilibrium exist, and they are all proven to be unstable even in the uncalibrated case. In other words, contrarily to existing 2D methods, there are no local minima. The paper details the control design and analysis and provides simulation results, emphasizing the remarkable robustness with respect to camera calibration errors.