Sainte-Foy-lès-Lyon, France


Sainte-Foy-lès-Lyon, France
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Cord A.,UniverSud | Aubert D.,University Paris Est Creteil
IEEE Intelligent Vehicles Symposium, Proceedings | Year: 2011

Advanced Driver Assistance Systems (ADAS) based on video camera tends to be generalized in today's automotive. However, if most of these systems perform nicely in good weather conditions, they perform very poorly under adverse weather particularly under rain. We present a novel approach that aims at detecting raindrops on a car windshield using only images from an in-vehicle camera. Based on the photometric properties of raindrops, the algorithm relies on image processing technics to highlight raindrops. Its results can be further used for image restoration and vision enhancement and hence it is a valuable tool for ADAS. © 2011 IEEE.

Gallen R.,CETMEF | Gallen R.,UniverSud | Cord A.,UniverSud | Hautiere N.,University Paris Est Creteil | Aubert D.,University Paris Est Creteil
IEEE Intelligent Vehicles Symposium, Proceedings | Year: 2011

Compared to daytime, a larger proportion of accident happens during nighttime. The altered visibility of the road scene for the drivers may partially explain this situation. The latter becomes worse in fog presence. In this paper, two camera-based methods are proposed to detect the presence of night fog in images grabbed by in-vehicle multipurpose cameras. They rely on the visual effects of night fog. A first approach can assess the presence of fog around the vehicle thanks to the detection of the backscattered veil induced by the vehicle ego lights. It aims at detecting fog when the vehicle is alone in absence of exterior public lighting. A second approach can assess the presence of fog thanks to the detection of halos around light sources in the vehicle environment. It aims at detecting fog in presence of road traffic or public lighting. Both methods are presented and illustrated with actual images of fog. Their complementarity makes it possible to envision a complete night fog detection system. There are numerous applications for such a system: automation or adaptation of vehicle lights, contextual speed computation and reliability improvement for camera-based systems. © 2011 IEEE.

Halmaoui H.,UniverSud | Cord A.,UniverSud | Hautiere N.,University Paris Est Creteil
Proceedings of the IEEE International Conference on Computer Vision | Year: 2011

Driver assistance systems based on camera are strongly disturbed by the presence of foggy weather. The restoration of images, as pre-processing, would improve the performances of such systems. In this paper, we propose a method to restore the image contrast of foggy road scenes combining a physical approach, based on Koschmieders model and a signals approach, based on local histogram equalization. Then we optimize the parameters of our method using a simulated annealing. This method, evaluated on a reference image database, presents a significant improvement compared to other methods and gives consistent results for both homogeneous and inhomogeneous fog. © 2011 IEEE.

Tarel J.-P.,University Paris Est Creteil | Hautiere N.,University Paris Est Creteil | Caraffa L.,University Paris Est Creteil | Cord A.,UniverSud | And 2 more authors.
IEEE Intelligent Transportation Systems Magazine | Year: 2012

One source of accidents when driving a vehicle is the presence of fog. Fog fades the colors and reduces the contrasts in the scene with respect to their distances from the driver. Various camera-based Advanced Driver Assistance Systems (ADAS) can be improved if efficient algorithms are designed for visibility enhancement in road images. The visibility enhancement algorithm proposed in [1] is not optimized for road images. In this paper, we reformulate the problem as the inference of the local atmospheric veil from constraints. The algorithm in [1] thus becomes a particular case. From this new derivation, we propose to better handle road images by introducing an extra constraint taking into account that a large part of the image can be assumed to be a planar road. The advantages of the proposed local algorithm are the speed, the possibility to handle both color and gray-level images, and the small number of parameters. A new scheme is proposed for rating visibility enhancement algorithms based on the addition of several types of generated fog on synthetic and camera images. A comparative study and quantitative evaluation with other state-of-the-art algorithms is thus proposed. This evaluation demonstrates that the new algorithm produces better results with homogeneous fog and that it is able to deal better with the presence of heterogeneous fog. Finally, we also propose a model allowing to evaluate the potential safety benefit of an ADAS based on the display of defogged images. © 2012 IEEE.

Hautiere N.,University Paris Est Creteil | Tarel J.-P.,University Paris Est Creteil | Halmaoui H.,UniverSud | Bremond R.,University Paris Est Creteil | Aubert D.,University Paris Est Creteil
Machine Vision and Applications | Year: 2014

Free-space detection is a primary task for car navigation. Unfortunately, classical approaches have difficulties in adverse weather conditions, in particular in daytime fog. In this paper, a solution is proposed thanks to a contrast restoration approach on images grabbed by an in-vehicle camera. The proposed method improves the state-of-the-art in several ways. First, the segmentation of the fog region of interest is better segmented thanks to the computation of the shortest routes maps. Second, the fog density as well as the position of the horizon line is jointly computed. Then, the method restores the contrast of the road by only assuming that the road is flat and, at the same time, detects the vertical objects. Finally, a segmentation of the connected component in front of the vehicle gives the free-space area. An experimental validation was carried out to foresee the effectiveness of the method. Different results are shown on sample images extracted from video sequences acquired from an in-vehicle camera. The proposed method is complementary to existing free-space area detection methods relying on color segmentation and stereovision. © 2011 Springer-Verlag.

Bui D.T.,UniverSud | Nguyen L.D.,UniverSud | Ledoux-Rak I.,UniverSud | Journet B.,UniverSud
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The stability of an electro-optic modulator has been significantly improved by implementing an original temperature control system. In particular, the evolution of the modulator characteristics can be followed through its nonlinear behavior by detecting the second harmonic of a low-frequency modulation signal; the evolution can be investigated with a higher accuracy by measuring also the phase-shift of this harmonic signal. Two digital boards have been developed with PSOC microcontrollers. The first one is associated with a small power amplifier for the temperature control; the second board is used to analyze the behavior of the electro-optic modulator. By thermal control of the modulator it is possible to reduce significantly the drift of its optical bias point. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Barrientos L.,French Institute of Health and Medical Research | Barrientos L.,UniverSud | Marin-Esteban V.,French Institute of Health and Medical Research | Marin-Esteban V.,UniverSud | And 14 more authors.
Frontiers in Immunology | Year: 2013

Netosis is a recently described neutrophil function that leads to the release of neutrophil extracellular traps (NETs) in response to various stimuli. NETs are filaments of decondensed chromatin associated with granular proteins. In addition to their role against microorganisms, NETs have been implicated in autoimmunity, thrombosis, and tissue injury. Access to a standardized source of isolated NETs is needed to better analyze the roles of NETs. The aim of this study was to develop a procedure yielding soluble, well-characterized NET preparations from fresh human neutrophils. The calcium ionophore A23187 was chosen to induce netosis, and the restriction enzyme AluI was used to prepare large NET fragments. DNA and proteins were detected by electrophoresis and specific labeling. Some NET proteins [histone 3, lactoferrin (LF)] were quantified by western blotting, and double-stranded DNA (dsDNA) was quantified by immunofluorescence. Co-existence of dsDNA and neutrophil proteins confirmed the quality of the NET preparations. Their biological activity was checked by measuring elastase (ELA) activity and bacterial killing against various strains. Interindividual differences in histone 3, LF, ELA, and dsDNA relative contents were observed in isolated NETs. However, the reproducibility of NET preparation and characterization was validated, suggesting that this interindividual variability was rather related to donor variation than to technical bias. This standardized protocol is suitable for producing, isolating, and quantifying functional NETs that could serve as a tool for studying NET effects on immune cells and tissues. © 2013 Barrientos, Marin-Esteban, de Chaisemartin, Le-Moal, Sandré, Bianchini, Nicolas, Pallardy and Chollet-Martin.

Li C.,East China Normal University | Qiu W.,East China Normal University | Yang Z.,East China Normal University | Luo J.,East China Normal University | And 4 more authors.
Steroids | Year: 2010

A series of 3-, 7-, 15-, and 16-methyl-substituted steroid analogs were synthesized via a highly stereoselective 1,6-conjugate addition. Under the catalysis of CuBr, AlMe3 reacted with four steroid dienone precursors to afford either the corresponding α-epimer of C-3 and C-7 methyl-substituted steroids as the major products, and the ratio of α/β was up to 10/1. No β-epimer has been detected for methyl addition at C-16. However, under the same reaction conditions, enantioselective methyl addition at C-15 afforded the 15β-epimer as the major product. The preliminary SAR analysis showed that the methyl substituents at C-7α and C-15β positions lead to a dramatical increase in potency against human gastric cancer cell line MGC-803. © 2010 Elsevier Inc.

Bui D.T.,UniverSud | Journet B.,UniverSud
ICCE 2010 - 3rd International Conference on Communications and Electronics | Year: 2010

In this paper, we present a study concerning the stabilization of an electrooptic modulator (EOM) by controlling its optical bias point. A digital proportional-integral-derivative (PID) controller using an auto-tuning algorithm has been developed with a PSOC microcontroller in order to keep the bias point at an optimal value. The evolution of the modulator characteristics can be followed through its nonlinear behavior by detecting the second harmonic of a low-frequency modulating signal. By such a bias point control of the EOM it is possible to compensate completely the effects of the modulator drift for duration of at least two hours. ©2010 IEEE.

PubMed | University of Alberta, Air Liquide, Ecole Polytechnique - Palaiseau, Apple USA and UniverSud
Type: | Journal: International journal of chronic obstructive pulmonary disease | Year: 2016

Oxygen treatment based on intermittent-flow devices with pulse delivery modes available from portable oxygen concentrators (POCs) depends on the characteristics of the delivered pulse such as volume, pulse width (the time of the pulse to be delivered), and pulse delay (the time for the pulse to be initiated from the start of inhalation) as well as a patients breathing characteristics, disease state, and respiratory morphology. This article presents a physiological-based analysis of the performance, in terms of blood oxygenation, of a commercial POC at different settings using an in silico model of a COPD patient at rest and during exercise. The analysis encompasses experimental measurements of pulse volume, width, and time delay of the POC at three different settings and two breathing rates related to rest and exercise. These experimental data of device performance are inputs to a physiological-based model of oxygen uptake that takes into account the real dynamic nature of gas exchange to illustrate how device- and patient-specific factors can affect patient oxygenation. This type of physiological analysis that considers the true effectiveness of oxygen transfer to the blood, as opposed to delivery to the nose (or mouth), can be instructive in applying therapies and designing new devices.

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