Flexible and miniaturized microscope for three dimensionnal measurements

ISBN: 978-1-4673-2875-3 INSPEC: 13250769International audienceIn three dimensional measurement systems, two properties are generally difficult to maximize simultaneously: compactness and measurement accuracy. Compactness can be obtained with miniaturized opto-electronic devices such as small cameras. However, quality (resolution, frame-rate, signal to noise ratio...) of these small devices is lower than standard sized ones. In this paper an alternative configuration is described where the opto-electronic devices are not miniaturized but optically connected to small probes through image guides. Instrumental description of this system is detailed and a measurement result is finally presented

Theme F "medical robotics for training and guidance": Results and future work

International audienceThis paper presents the projects of the Theme F "medical robotics for training and guidance" inside the GdR STIC-Santé. Three scientific meeting days have been organized during the period 2011-2012. They were devoted to physical simulators of behavior for gesture learning, command of hand prostheses by myoelectric signals or brain activity and the manipulation of objects by the artificial hand, and the last to the use of robots for medical gestures. The next event, scheduled for early 2013, will focus on the evaluation of gesture and especially "evaluation of gesture - to do what?"

Tri-dimensional optical inspection based on flexible image guide: first step toward 3D industrial endoscopy

International audience3D optical endoscopy is now a major challenge to allow the high resolution inspection of industrial equipments. The proposed instrument is based on a flexible image guide (70 000 fibres) and a Digital Micro mirror Device (DMD, 1024 x 768 "on-off" micro mirrors). The optical design is as follows: the light emitted by a 532 nm laser diode is dynamically structured by the DMD chip as a fringes pattern which is phase-shifted due to the active control of the DMD chip and projected onto an object on a circular field of 6 mm in diameter. Due to a telecentric and binocular arrangement that creates a stereoscopic angle, it is possible to get a depth of field of 2 mm along the optical axis without keystone distortions and few disturbances created by defocus and coma aberrations. Then, images are captured by a 1024 x 768 digital camera (not yet moved away by fibres) at 15 fps and directly used in the reconstruction algorithm to access the tri-dimensional shape of the unpainted object. The results are compared to incoherent white light results obtained with white painted mechanical objects. The lateral resolution is 31.3 µm and the RMS axial resolution is 10 µm for the laser-based design after speckle attenuation

A Compact Active Stereovision System with Dynamic Reconfiguration for Endoscopy or Colonoscopy Applications

International audienceA new concept of endoscopic device based on a compact optical probe which can capture 3D shape of objects using an active stereovision method is presented. The distinctive feature of this probe is its capability to dynamically switch between two distinct points of view. If the first measurement angle of view does not give results with sufficient quality, the system can switch to a second mode which sets distinct angle of view within less than 25 milliseconds. This feature consequently allows selecting the angle that provides the more useful 3D information and enhances the quality of the captured result. The instrumental setup of this measurement system and the reconstruction algorithms are presented in this paper. Then, the advantages of this new endoscopic probe are explained with an experimental 3D reconstruction of a coin's surface. Finally, first measurements on a phantom colon are provided. In future works, further miniaturization of the device and its integration into a real colonoscope will be implemented

Binary pattern codification strategies in an active stereoscopic system based on flexible image guides

International audienceA wide variety of three dimensional (3D) measurement systems that can extract shape information's with sub millimetric accuracy is available in the industry. However, they generally are of macroscopic size and measuring on confined areas is not feasible. To miniaturize such systems, the step proposed is the integration of flexible image guides combined with compact optical probes. This miniaturization process is tested on an active stereoscopic measurement system. In the projection channel of the system, a digital micro-mirror device (DMD) generates structured binary patterns from an incoherent white light source and injects them into a first image guide. Then, a compact optical system projects the pattern on the measurement area. The same configuration principle is applied to the acquisition channel and allows the capture of the measurement area through a second image guide and finally to a digital camera. In this miniaturized system, image guides have lower resolution than in standard imaging devices. Indeed they are equivalent of 70k pixels devices to compare to the almost 800k pixels of the DMD and camera. That implies lower axial and lateral resolutions and consequently the shape reconstruction method must be carefully chosen. In this paper, several reconstruction strategies such as tuning the projected patterns frequency and also phase-shfit versus gray code based methods were compared considering the best axial resolution criteria

Abbayes, couvents et monastères devenus dépôts d’étalons impériaux, royaux et nationaux

La Révolution française de 1789-1793 a vidé et confisqué les abbayes, les couvents, les monastères et tous les établissements abritant des congrégations religieuses. En y installant des dépôts d’étalons et des dépôts de remonte militaire, Napoléon 1er en a sauvé un certain nombre entre 1806 et 1814. De très nombreux autres établissements sont devenus des carrières de pierres et ont disparu. Les évolutions stratégiques, politiques et techniques des armées et des haras nationaux font que certains de ces édifices historiques seront progressivement et à nouveau en grand danger

An Energy-Based Approach for n-dof Passive Dual-user Haptic Training Systems

International audienceThis paper introduces a dual-user training system whose design is based on an energetic approach. This kind of system is useful for supervised hands-on training where a trainer interacts with a trainee through two haptic devices, in order to practice on a manual task performed on a virtual or teleoperated robot (for example for an MIS task in a surgical context). This paper details the proof of stability of an Energy Shared Control (ESC) architecture we previously introduced for one degree of freedom (d.o.f.) devices. An extension to multiple degrees of freedom is proposed, along with an enhanced version of the Adaptive Authority Adjustment (AAA) function. Experiments are carried out with 3 d.o.f. haptic devices in free motion as well as in contact contexts in order to show the relevance of this architecture

Kiri tundmatule

Duchatel de Tanneguy, Charles Marie, 1803-1867, prantsuse riigitegelaneTänukir