Scheimpflug Self-Calibration Based on Tangency Points

International audienceSPIV self-calibration strongly depends on the accuracy of the detection of the projection of the control points. A new family of control points and an algorithm of image detection are proposed to overcome the bias associated to the use of dot centers as control points in SPIV self-calibration

Contributions à la vision non-calibrée d'une scène plane

Cette thèse propose un point de vue alternatif sur trois problèmes de vision non-calibrée en présence d une scène plane : l auto-calibrage plan, l estimation d homographies entre ellipses et l utilisation de cercles pour obtenir une information métrique. Le fil conducteur est une vision à la fois géométrique et physique des problèmes d estimation sous-jacents à ces trois questions. Ces travaux sont en ce sens à mi-chemin entre vision 3D et photogrammétrie. Dans le problème d auto-calibrage plan, la rectification métrique des images d une scène plane est mise en avant et exploitée grâce à deux nouvelles idées. La première est une décomposition de la rectification en fonction des paramètres intrinsèques et de l orientation du plan. La seconde est une contrainte d auto-calibrage se traduisant assez naturellement en une fonction de coût à caractère géométrique. Une troisième contribution est de mettre en évidence les liens théoriques entre cette approche et celles existantes. Le second volet de la thèse porte sur l estimation d homographies inter-images grâce à la correspondance d au moins deux ellipses dans les images. Le problème est abordé en utilisant les quatre bitangentes à une paire d ellipses. Un calcul efficace des bitangentes est d abord présenté. Une technique de mise en correspondance dense des images est ensuite proposée. Un certain nombre de points en correspondance sont finalement sélectionnés sur les ellipses pour déterminer l homographie par une technique classique. Enfin, nous proposons une solution simple et efficace pour calculer la rectification métrique d une image dans laquelle au moins 2 cercles ont été identifiés. Cette méthode fonctionne pour un nombre quelconques de cercles, sécants ou non, et repose sur la minimisation d une erreur portant sur l orthogonalité de droites réelles du plan. L extension au cas multi-images est directe et permet de calibrer la caméra. Une solution spécifique pour le calibrage est toutefois proposée, afin d imposer a priori certaines contraintes sur les paramètres à estimerThis work presents some new insights into uncalibrated vision of a planar structure. Three problems are addressed : plane-based camera self-calibration, homography estimation from ellipses and metric rectification / calibration from circles. Our approach is driven by a geometric and physical viewpoint, hence designed to be a trade-off between 3D vision and photogrammetry. Metric rectification of perspective images of a plane is the key concept used in our plane-based self calibration approach. Two novel ideas are given. First, we propose a decomposition of the rectification in terms of intrinsic parameters and plane orientation. Secondly, we formulate a selfcalibration constraint which translates gracefully into a geometric cost function.We also highlight the theoretical connections between our approach and prior work. The second part of the document deals with the estimation of inter-image homographies given the correspondence of at least two ellipses in multiple images. This problem is tackled by using the four bitangents to a couple of ellipses. First, an efficient solution for the computation of bitangents is proposed. Then, a technique for dense correspondence of images is introduced. Finally, few corresponding points are selected to estimate homographies, following a classical point-based method. Our last contribution is a simple and efficient solution to obtain metric rectification from an image containing at least two circles. This method can cope with an arbitrary number of circles, intersecting or not. It is based on the minimization of a cost function involving the orthogonality constraints of certain real lines in the scene plane. The extension to multiple views isST ETIENNE-BU Sciences (422182103) / SudocSudocFranceF

Plane-based camera self-calibration by metric rectication of images

International audienc

ViKY Robotic Scope Holder: Initial Clinical Experience and Preliminary Results Using Instrument Tracking

International audienceRobotic endoscope holders constitute an alternative to complete telesurgery systems, by offering a "third hand" to the surgeon during a laparoscopic procedure. ViKY robotic scope holder (Endocontrol, Grenoble, France) is a lightweight, sterilizable body-mounted robot with 3 DOF. In this paper, we present the specifics of this robot, the newly developed XL version dedicated to single-port surgery and the initial clinical experience. We have proposed a method to control the robot, based on the detection and tracking of surgical instrument from image analysis and shape priors, to enrich the interaction between the surgeon and the robot. We present here, our work in progress toward its integration into a probabilistic framework, with the aim of improving the method's speed and robustness. We also present the surgeons' viewpoints on the feasibility of its integration into the operating theater

Managing innovative design within the health ecosystem: the Living Lab as an architect of the unknown

International audienceDesigning new technological products or services for improving health care raises many challenges today, namely improving the innovative care process, bringing health actors to develop new value propositions and reconciling the logic of business and the logic of social economy around health. The health ecosystem is not the only sector in which such an issue emerges. Indeed, the question of the management of an industrial ecosystem arises today in many sectors seeking a renewal of their capabilities for innovation. In such situations, empirical and theoretical studies show the emergence of new actors--innovation intermediaries--who aim to influence the innovation process. Recently, scholars have enriched the description of the diversification of the role of such actors, showing how those actors can take a more active role within the innovation process. Our goal in this paper is to examine the role that Living Labs can play in the health ecosystem as architects of the unknown, i.e., innovation intermediaries acting to improve the innovation capabilities of other stakeholders. Building on both a description of the contemporary stakes of innovating in the health ecosystem and the literature on innovation intermediaries, we examine a case study in the Rhône-Alpes region in France in which we show how structures like Living Labs can act as architects to stimulate innovation and to help new concepts to emerge. This article therefore contributes to deepen the emerging stream of research that studies the concept of Living Labs and enriches our understanding of the activities that innovation intermediaries can undertake within the health ecosystem

ID2U Project: Single use dexterous surgical instrument

Le projet ID2U a porté sur la mise au point de différentes technologies pour la conception d’un instrument articulé destiné à la chirurgie mini-invasive. Une étude prospective sur les mobilités distales possibles a d’abord été menée. Puis des technologies d’actionnement fluidique couplées à des structures flexibles ont été développées pour réaliser l’outil distal. Enfin, une structure mécanique extracorporelle ergonomique a été proposée pour aboutir à un concept complet et nouveau d’instrument chirurgical