From Driving Simulation to Virtual Reality

Driving simulation from the very beginning of the advent of VR technology uses the very same technology for visualization and similar technology for head movement tracking and high end 3D vision. They also share the same or similar difficulties in rendering movements of the observer in the virtual environments. The visual-vestibular conflict, due to the discrepancies perceived by the human visual and vestibular systems, induce the so-called simulation sickness, when driving or displacing using a control device (ex. Joystick). Another cause for simulation sickness is the transport delay, the delay between the action and the corresponding rendering cues. Another similarity between driving simulation and VR is need for correct scale 1:1 perception. Correct perception of speed and acceleration in driving simulation is crucial for automotive experiments for Advances Driver Aid System (ADAS) as vehicle behavior has to be simulated correctly and anywhere where the correct mental workload is an issue as real immersion and driver attention is depending on it. Correct perception of distances and object size is crucial using HMDs or CAVEs, especially as their use is frequently involving digital mockup validation for design, architecture or interior and exterior lighting. Today, the advents of high resolution 4K digital display technology allows near eye resolution stereoscopic 3D walls and integrate them in high performance CAVEs. High performance CAVEs now can be used for vehicle ergonomics, styling, interior lighting and perceived quality. The first CAVE in France, built in 2001 at Arts et Metiers ParisTech, is a 4 sided CAVE with a modifiable geometry with now traditional display technology. The latest one is Renault’s 70M 3D pixel 5 sides CAVE with 4K x 4K walls and floor and with a cluster of 20 PCs. Another equipment recently designed at Renault is the motion based CARDS driving simulator with CAVE like 4 sides display system providing full 3D immersion for the driver. The separation between driving simulation and digital mockup design review is now fading though different uses will require different simulation configurations. New application domains, such as automotive AR design, will bring combined features of VR and driving simulation technics, including CAVE like display system equipped driving simulators

Synthesis by sol-gel process, structural and optical properties of nanoparticles of zinc oxide doped vanadium

International audienceWe report the elaboration of vanadium-doped ZnO nanoparticles prepared by a sol-gel processing technique. In our approach, the water for hydrolysis was slowly released by esterification reaction followed by a supercritical drying in ethyl alcohol. Vanadium doping concentration of 10 at.% has been investigated. After treatment in air at different temperatures, the obtained nanopowder was characterised by various techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and photoluminescence (PL). Analysis by scanning electron microscopy at high resolution shows that the grain size increases with increasing temperature. Thus, in the case of thermal treatment at 500 degrees C in air, the powder with an average particle size of 25 nm shows a strong luminescence band in the visible range. The intensity and energy position of the obtained PL band depends on the temperature measurement increase. The mechanism of this emission band is discussed. (c) 2012 Elsevier Ltd. All rights reserved

Synthesis, structural and optical properties of nanocrystalline vanadium doped zinc oxide aerogel

International audienceWe report the synthesis of vanadium-doped ZnO nanoparticles prepared by a sal-gel processing technique. In our approach, the water for hydrolysis was slowly released by esterification reaction followed by a supercritical drying in ethyl alcohol. Vanadium doping concentration of 10 at% has been investigated. After treatment in air at different temperatures, the obtained nanopowder was characterized by various techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and photoluminescence (PL). Analysis by scanning electron microscopy at high resolution shows that the grain size increases with increasing temperature. Thus, in the case of thermal treatment at 500 degrees C in air, the powder with an average particle size of 25 nm shows a strong luminescence band in the visible range. The intensity and energy position of the obtained PL band depends on the temperature measurement increase. The mechanism of this emission band is discussed. (C) 2012 Elsevier B.V. All rights reserved

In situ synthesis of Zn2SiO4:V obtained by incorporation of ZnO:V nanoparticles in silica host matrix

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Optical characterization of SiO2/Zn2SiO4:V nanocomposite obtained after the incorporation of ZnO:V nanoparticles in silica host matrix

International audienceVanadium-doped Zn2SiO4 particles embedded in silica host matrix were prepared by a simple solid-phase reaction under natural atmosphere at 1200 degrees C after the incorporation of ZnO:V nanoparticles in silica monolith using 501 gel method with supercritical drying of ethyl alcohol in two steps. The obtained sample, exhibits a strong PL band in the visible range at 540 nm and two thin emission lines in the UV range at 394 and 396 nm under intensive power excitation. Photoluminescence excitation (PLE) measurements show different origins of the emission bands. It is suggested that radiative defects attributed to vanadium in the interfaces between Zn2SiO4 particles and SiO2 host matrix resulting from heat treatment and zinc oxide excitonic emissions, were responsible for theses luminescence bands. (C) 2009 Elsevier Ltd. All rights reserved

Synthesis and optical characterization of SiO2/Zn2SiO4:Mn nanocomposite

International audienceManganese-doped Zn2SiO4 particles imbedded in silica host matrix were successfully prepared by a simple solid-phase reaction under natural atmosphere at 1200 degrees C for 2 h after the incorporation of ZnO:Mn nanoparticles in silica aerogel monolith using sol-gel method with supercritical drying of ethyl alcohol in two steps. The obtained sample, exhibits a strong photoluminescence (PL) bands in the visible range at 525 and 610 nm. Photoluminescence excitation (PLE) measurements show different origins of the emission. It was suggested that electronic transition associated with Mn2+ ions in willemite and the presence of Mn2+ in intensive crystal field were responsible for theses luminescence bands. In the other hand, this emission of the final composite is time stable: no change in the spectra was observed even after being aged for over 1 year. (C) 2009 Elsevier B.V. All rights reserved