Nicolas Andreff

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In this paper, we propose a new flexible method for hand-eye calibration. The vast majority of existing hand-eye calibration techniques require a calibration rig that is used in conjunction with camera pose estimation methods. Instead, we combine structurefrom-motion with known robot motions, and we show that the solution can be obtained in linear form. The(More)
An original concept for computing instantaneous 3D pose and 3D velocity of fast moving objects using a single view is proposed, implemented and validated. It takes advantage of the image deformations induced by rolling shutter in CMOS image sensors. First of all, after analysing the rolling shutter phenomenon, we introduce an original model of the image(More)
In this paper we present a new approach to visual servoing using lines. It is based on a theoretical and geometrical study of the main line representations which allows us to define a new representation, the so-called binormalized Plücker coordinates. They are particularly well suited for visual servoing. Indeed, they allow the definition of an image line(More)
In this paper, we address the problem of hand-eye calibration of a robot mounted video camera. In a rst time, we derive a new linear formulation of the problem. This allows an algebraic analysis of the cases that usual approaches do not consider. In a second time, we extend this new formulation into an on-line hand-eye calibration method. This method allows(More)
In this paper we address visual servoing through a xed stereo rig using an image Jacobian. Existing methods are based on the stacking of monocular servo image Jacobians, resulting in largely over-constrained control commands. In this paper we formally show that the epipolar constraint between two images can be taken into account explicitly. We then show(More)
In this article, a review on parallel kinematic machine dynamic control is performed. It is shown that the classical control strategies from serial robotics generally used for parallel kinematic machine have to be thought again. Indeed, it is first shown that the joint space control is not relevant for these mechanisms for several reasons such as mechanical(More)
In this paper, a vision-based measuring device is proposed and experimentally demonstrated to be an accurate, flexible, and low-cost tool for the kinematic calibration of parallel mechanisms. The accuracy and ease of use of the proposed vision sensor are outlined, with the suppression of the need for an accurate calibration target, and adequacy to the(More)
Recent work shows that recovering pose and velocity from a single view of a moving rigid object is possible with a rolling shutter camera, based on feature point correspondences. We extend this method to line correspondences. Owing to the combined effect of rolling shutter and object motion, straight lines are distorted to curves as they get imaged with a(More)
In this paper, a novel approach is proposed for the kinematic calibration of parallel mechanisms with linear actuators at the base. The originality of the approach lies in the observation of the mechanism legs with a camera, without any mechanism modification. The calibration can hence be achieved online, as no calibration device is linked to the(More)
In this paper, an original approach is proposed for the kinematic calibration of parallel mechanisms. The originality lies in the use of vision to get information on all parts of the mechanism, i.e. its end-effector as well as its legs. Metrological redundancy is therefore maximized to improve the calibration efficiency. The approach is implemented for the(More)