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In this paper, the classical visual servoing techniques have been extended to the use of several cameras observing different parts of an object. The multi-camera visual servoing has been designed as a part of the task function approach.... more
In this paper, the classical visual servoing techniques have been extended to the use of several cameras observing different parts of an object. The multi-camera visual servoing has been designed as a part of the task function approach. The particular choice of the task function allows us to simplify the design of the control law and the stability analysis. A
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The authors present a method to estimate the inverse Jaco- bian matrix of a function, without computing the direct Ja- cobian matrix. This kind of inverse Jacobian matrix proves to perform much better in modeling a relation than the... more
The authors present a method to estimate the inverse Jaco- bian matrix of a function, without computing the direct Ja- cobian matrix. This kind of inverse Jacobian matrix proves to perform much better in modeling a relation than the traditionnal computation of the Moore-Penrose in- verse Theoretical insight as well as comparisons in the domain of visual servoing are provided
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This paper presents new advances in the field of visual servoing. More precisely, we consider the case where complex objects are observed by a camera. In a first part, planar objects of unknown shape are considered using image moments as... more
This paper presents new advances in the field of visual servoing. More precisely, we consider the case where complex objects are observed by a camera. In a first part, planar objects of unknown shape are considered using image moments as input of the image-based control law. In the second part, a pose estimation and tracking algorithm is described to deal with real objects whose 3D model is known. For each case, experimental results obtained with an eye-in-hand system are presented.
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This paper presents an active approach for the task of computing the 3-D structure of a nuclear plant environment from on image sequence, more precisely the recovery of the 3-D structure of cylindrical ob-jects. Active vision is... more
This paper presents an active approach for the task of computing the 3-D structure of a nuclear plant environment from on image sequence, more precisely the recovery of the 3-D structure of cylindrical ob-jects. Active vision is considered by computing adequate camera motions using image-based control laws. This approach requires a real-lime tracking of the limbs of the cylinders. Therefore, an original matching approach, which relies on an algorithm for determining moving edges, is proposed. This method is distinguished by its robustness and its easiness to implement. This method has been implemented on a parallel image processing board and real-time performance has been achieved. The whole scheme iias been successfully validated in an experimental set-up.
Cet article de synthèse présente les avancées réalisées en France au cours de ces quatre dernières années dans le domaine de l'asservissement visuel.
Efficient real-time robotic tasks using a monocular vision system were previously developed with simple objects (e.g. white points on a black background), within a visual servoing context. Due to recent developments, it is now possible to... more
Efficient real-time robotic tasks using a monocular vision system were previously developed with simple objects (e.g. white points on a black background), within a visual servoing context. Due to recent developments, it is now possible to design real-time visual tasks exploiting motion information in the image, estimated by robust algorithms. This paper proposes such an approach to track complex objects, such as a pedestrian. It consists in integrating the measured 2D motion of the object to recover its 2D-position in the image. The principle of the tracking task is to control the camera pan and tilt such that the estimated center of the object appears at the center of the image. Real-time experimental results demonstrate the efficiency and the robustness of the method. 1.
Visual servoing based upon geometrical features such as image points coordinates is now well set on. Never- theless, this approach has the drawback that it usually needs visual marks on the observed object to retrieve ge- ometric... more
Visual servoing based upon geometrical features such as image points coordinates is now well set on. Never- theless, this approach has the drawback that it usually needs visual marks on the observed object to retrieve ge- ometric features. The idea developed here is that these features can be retrieved by integrating dynamic ones, which can be estimated without any a
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Visual servoing is generally based upon geometrical features. Recent developments were made in the way of a generalization of this approach to dynamic features. The idea is that velocity in the image can be measured without the constraint... more
Visual servoing is generally based upon geometrical features. Recent developments were made in the way of a generalization of this approach to dynamic features. The idea is that velocity in the image can be measured without the constraint of having an a priori knowledge of the scene. In this paper, a control law to position a camera mounted on the
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1 Réalisation du capteur François BERRY -LASMEA Dans ce chapitre, on se propose de présenter le capteur réalisé ainsi que les permiers résultats obtenus. Une large place sera laissée Á a la description technique, ce qui perme-ttera... more
1 Réalisation du capteur François BERRY -LASMEA Dans ce chapitre, on se propose de présenter le capteur réalisé ainsi que les permiers résultats obtenus. Une large place sera laissée Á a la description technique, ce qui perme-ttera d'argumenter sur les limites de la réalisation.
Le projet Omnibot a pour principaux objectifs, la conception et l'optimisation d'une boucle perception-commande, en partant du composant (imageur) jusqu'à la navigation du robot. Cette approche originale permet ainsi la... more
Le projet Omnibot a pour principaux objectifs, la conception et l'optimisation d'une boucle perception-commande, en partant du composant (imageur) jusqu'à la navigation du robot. Cette approche originale permet ainsi la création d'une nouvelle génération de capteurs pour la vision omnidirectionnelle tout en gardant une interaction constante avec des applications réelles. L'objectif final de ce projet est de proposer un démonstrateur mettant en œuvre un robot mobile command par un asservissement visuel omndirectionnel. Ce projet fait actuellement l'objet des quatre parties qui sont développées ci après.
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ABSTRACT
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In this paper we consider the problem of controlling the six degrees of freedom of a manipulator using the projection of 3D lines in the image plane of central catadioptric systems. Most of the efiort in visual servoing are devoted to... more
In this paper we consider the problem of controlling the six degrees of freedom of a manipulator using the projection of 3D lines in the image plane of central catadioptric systems. Most of the efiort in visual servoing are devoted to points, only few works have investigated the use of lines in visual servoing with traditional cameras and none has
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A new visual servoing technique based on 2D ultrasound image is proposed in order to control the motion of an ultrasound probe held by a medical robot. In opposition to a standard camera which provides a projection of the 3D scene to a 2D... more
A new visual servoing technique based on 2D ultrasound image is proposed in order to control the motion of an ultrasound probe held by a medical robot. In opposition to a standard camera which provides a projection of the 3D scene to a 2D image, ultrasound information is strictly in the observation plan of the probe and consequently visual servoing