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Die vorliegende Arbeit untersucht die Ablenkbarkeit von Personen in Einkaufssituationen. Dabei wird zwischen typischen Produkten aus dem Supermarktkontext unterschieden, die eine Rabattmarkierung aufweisen und Produkten, bei denen eine solche Rabattmarkierung fehlt. Die Ablenkung sollte, gestützt durch Forschungsarbeiten zur Rabattwirksamkeit, für Rabattprodukte am größten sein. Außerdem wird durch eine Vignettenaufgabe versucht, Personen in zwei verschiedene Modi zu versetzen, sodass sich die Gruppen in ihrem impulsiven Kaufverhalten unterscheiden. Auch die generelle Impulskaufneigung wird erfasst. Die beiden Gruppen sollten sich in einer, durch einen Eyetracker aufgezeichneten, Konzentrationsaufgabe, in ihrer Ablenkbarkeit durch das Rabattprodukt, unterscheiden. Die generelle Impulskaufneigung sollte sich ebenfalls, auf die Ergebnisse auswirken. Aktuellen Forschungsarbeiten zu Folge, haben Impulskäufer eine mangelnde Fähigkeit, sich in Einkaufsituationen von verführerischen Reizen abzuschirmen. Eine im Anschluss an die Konzentrationsaufgabe durchgeführte Merkfähigkeitsaufgabe soll den Unterschied der beiden Gruppen und der generellen Impulskaufneigung auf die Merkfähigkeit belegen. Die Ergebnisse der Untersuchungen, an 43 Teilnehmern, können einen wichtigen Einfluss von Rabattmarkierungen auf die Ablenkung nachweisen. Die Zugehörigkeit zu einem bestimmten Modus und die generelle Impulskaufneigung, haben allerdings keinen Einfluss., This research adresses to the diversation of people in shopping situations and focuses especially on differences in the visual distraction in consequence of eye catching promotional offers. For this, participants were confronted with typical products in a supermarkt context – some with a rebate symbol and some products without a rebate symbol. Previous researche showed efficacy of rebate promotion therefore it is hypothesize that there is more distraction fort he rebate product. In addition the participants were devided into two groups by using a manipulation task. As a result there occured two groups which differed in their individual impulsive buying tendencies. Furthermore the general impulsive buying tendency of all participants was determined. The presumption in this study is that the two groups should differ in their distractibility by the rebate products in a following concentration task which were detected by eye tracking. This presumption is based on the results of several studies which have illustrated that impulsive buyers are less successful in their ability to protect themselves against tempting products in shopping situations. Moreover the general impulsive buying tendency should also have an influence on the visual distraction of the participants in this study. A memory task which was enforced after the concentration task should show the discrepancy in retentiveness between the two buying tendencies induced groups and also the general buying impulsive tendency. The results of this research on 43 participants showed that rebate symbols have an important influence on the visual distraction. Unfortunately the affiliation to a group and the general impulsive buying tendency had no influence on the visual distraction or the results in the memory-task.

In this thesis, the object of study are robot-vision systems consisting of robot manipulators and stereo cameras. It investigates how to model, calibrate, and operate such systems, where operation refers especially to visual servoing of a tool with respect to an object to be manipulated. The main contributions of this thesis are to introduce a novel, "projective" geometrical formalization of these three problems, and to develop novel coordinate- and calibration-free solutions to them. The impact in practice: the "projective" systems can operate with less priori knowledge. Only metrically unstratified but projectively unified parameters are needed to "calibrate" a fully operational model of the system. This can be done automatically with a self-calibration method. As far as visual servoing is concerned, the projective models are equivalent to classical ones. Also, their particular properties allow new answers to open questions in visual servoing to be found, such as how to control trajectories that are at the same time visually and mechanically feasible over the entire work-space. The impact on theory: a novel and complete projective framework has been introduced, that allows calibration-free representations for all basic geometrical objects relevant to visual servoing, or to camera-based perceptionaction cycles in general. Most important are the projective representations of rigid- and articulated motion, as well as the respective notion of projective velocities. Effective computational methods for the numerical treatment of these representations were also developed., Cette thèse propose un nouvel éclairage sur le couplage de la vision stéréoscopique avec le mouvement articulé. Elle développe tout particulièrement de nouvelles solutions s'appuyant sur la géométrie projective. Ceci permet notamment l'utilisation des caméras non-calibrées. La contribution de cette thèse est d'abord une nouvelle formulation géométrique du problème. Il en découle des solutions pratiques pour la modélisation, l'étalonnage, et la commande du système. Ces solutions suivent une approche "coordinate-free", généralisées en une approche "calibration-free". C'est à dire, elles sont indépendantes du choix des repères et de l'étalonnage des caméras. Sur le plan pratique, un tel système projectif peut fonctionner sans connaissance a priori, et l'auto-étalonnage projectif se fait de manière automatique. Les modèles proposés sont issues d'une unification projective de la géométrie du système plutôt que d'une stratification métrique. Pour un asservissement visuel, les modèles obtenus sont équivalents aux modèles classiques. D'autres questions pratiques ont ainsi pu être abordées d'une nouvelle manière: la commande de trajectoires visibles et méchaniquement realisables dans l'espace de travail entier. Sur le plan théorique, un cadre mathématique complet est introduit. Il donne à l'ensemble des objets impliqués dans un asservissement visuel une représentation projective. Sont notamment etudiés, l'action des joints rotoïdes et prismatiques, les mouvements rigides et articulés, ainsi que la notion associée de vitesse projective. Le calcul de ces représentations est de plus explicité.

Visual servoing of robot manipulators is a key technique where video images, i.e. the visual appearance of an object is used to control the end-effector. Most such methods use robots and cameras that have been calibrated. In this report we suggest a non-metric formulation of visual servoing that works with an uncalibrated stereo rig, i.e. in the projective space associated with it. In consequence, the robot kinematics and the robot Jacobian have to defined projectively, as well. Elementary motions of robot joints are pure rotations and pure translations. Rather than representing them by Euclidean transformations, the uncalibrated stereo rig suggests to represent them by corresponding projective transformations (homographies). They are introduced as projective rotations and projective translations, their algebraic properties and special parameterizations are thoroughly investigated- . This gives raise to the definition of a projectiv kinematic map and a projective Jacobian matrix. Unlike the classical robot Jacobian, which relates joint-velocities to end-effector velocities, we establish a direct relationship between joint-velocities and image-velocities, i.e. the velocitie- s of those images points corresponding to end-effector features. Finally, we provide a practical method to establish the projective kinematics and describe preliminary simulated experiments of stereo-based visual servoing using the non-metric model. Nevertheless, in depth analysis of projective control will be the topic of a forthcoming paper.

International audience; This paper presents a new approach to controlling a robot from video-feedback. In contrast to classical approaches, the entire system is modeled by means of projective geometry. For the robot?s geometry in particular, we introduce a new formalism ?projective kinematics?. As a result, motions in joint- and image-space can be related without metric calibration, and a corresponding visual control law can be derived. We present experiments for projective robot calibration and visual servoing, both using uncalibrated cameras.

International audience; This paper proposes a methodological framework for trajectory generation in projective space. The framework en-ables trajectories that respect rigidity constraints of structure and motion, that are furthermore uniform and optimal in terms of Euclidean configuration, eventhough no camera calibration is assumed. In a projective reconstruction of the scene, obtained e.g. from an uncalibrated stereo-rig, the homography between corresponding feature points on a rigid object in different positions is employed to represent its spatial configuration. From its algebraic structure -it is similar to a rigid motion -decoupling of rotation and translation, and uniform interpolation of trajectories are derived. Speaking in robotic terms, the merely point-to-point definitions of goals, as present in current approaches to visual servoing, are extended to a guarded motion along via points on complete-path trajectories which result from interpolation of a demanded type of motion. Translationonly, rotation-first, rotation-last task-functions are further explicited.