Road detection and vehicles tracking by vision for ACC

This article deals with a process designed first to extract the lane of vehicle by on-board monocular vision. This detection process is based upon a recursive updating of a statistical model of the lane obtained by a training phase. Once the lane has been located, a reconstruction algorithm computes the vehicle location on its lane and the 3D shape of the road. Thereafter, we are focus at the detection, location and tracking of front vehicles equipped with specific visual markers in order to achieve an accurate determination of the location and speed of these vehicles. Merging these various informations allows to point out the most dangerous obstacle. Each of these three processes is detailed significant examples are provide.Cet article présente, dans un premier temps, un procédé permettant de détecter la voie de circulation d'un véhicule par vision monoculaire embarquée. Ce processus de détection est basé sur une mise à jour récursive d'un modèle statistique de la voie obtenu par une phase d'apprentissage. Après avoir localisé la voie, un algorithme de reconstruction détermine la position du véhicule dans sa voie de circulation et le profil 3D de la route. Par la suite, nous nous intéressons à la détection, la localisation et surtout le suivi des véhicules situés à l'avant et équipés de marques visuelles afin de déterminer avec précision la position et la vitesse relative de ces véhicules. La combinaison de ces différentes informations permet de déterminer le véhicule le plus dangereux. La description détaillée de chacune des étapes de notre algorithme est suivie d'exemples significatifs

Alcohol exposure during late gestation: Multiple developmental outcomes in sheep

Alcohol consumption during pregnancy remains common in many countries. Exposure to even low amounts of alcohol (i.e. ethanol) in pregnancy can lead to the heterogeneous fetal alcohol spectrum disorders (FASD), while heavy alcohol consumption can result in the fetal alcohol syndrome (FAS). FAS is characterized by cerebral dysfunction, growth restriction and craniofacial malformations. However, the effects of lower doses of alcohol during pregnancy, such as those that lead to FASD, are less well understood. In this article, we discuss the findings of recent studies performed in our laboratories on the effects of fetal alcohol exposure using sheep, in which we investigated the effects of late gestational alcohol exposure on the developing brain, arteries, kidneys, heart and lungs. Our studies indicate that alcohol exposure in late gestation can (1) affect cerebral white matter development and increase the risk of hemorrhage in the fetal brain, (2) cause left ventricular hypertrophy with evidence of altered cardiomyocyte maturation, (3) lead to a decrease in nephron number in the kidney, (4) cause altered arterial wall stiffness and endothelial and smooth muscle function and (5) result in altered surfactant protein mRNA expression, surfactant phospholipid composition and pro-inflammatory cytokine mRNA expression in the lung. These findings suggest that fetal alcohol exposure in late gestation can affect multiple organs, potentially increasing the risk of disease and organ dysfunction in later life

Commande de véhicule utilisant la reconnaissance d'indices image

Since several years, researchers attempt to design algorithms able to control a vehicle by using computer vision. Several approaches are now available but more often the vehicle control is achieved in separate way from the perception task. Indeed the vehicle state is combined with perception parameters to feed the regulation task. This paper presents the reliability of an original approach which combines perception and control task. The system we have designed is able to recognize roadsides from images cues in different situations (highway, road, etc), and to compute the vehicle wheel angle and several location parameters too. In particular, we present the need for achieving a training stage (given either by a control law or by a experimented human driver) to provide a good control law. The algorithm behavior is then presented in simulated and real situations as well in order to prove the reliability of the approach on an agricultural vehicle.Depuis plusieurs années, les chercheurs essayent de concevoir des algorithmes capables de commander un véhicule en employant la vision par ordinateur. Plusieurs approches sont maintenant disponibles mais le plus souvent, la commande du véhicule est réalisée en dehors de la tâche de perception. En effet l'état du vehicule est associé avec des paramètres de perception pour alimenter la tâche de régulation. Cet article présente la robustesse d'une approche originale qui combine la tâche de perception et la tâche de commande. Le système que nous avons conçu peut reconnaître les bords de la route à partir d'indices d'images en différentes situations (autoroute, route, etc..), et calculer l'angle des roues du véhicule ainsi que plusieurs paramètres de localisation. En particulier, nous présentons le besoin de la réalisation d'une étape d'apprentissage (réalisée par une loi de commande ou par un conducteur humain expérimenté) pour permettre une bonne loi de commande. Le comportement de l'algorithme est présenté dans des situations simulées et réelles sur un véhicule agricole

The effect of feeding animals ad libitum versus at maintenance level on the in vivo digestibility of two permanent grasslands across the first cycle of growth

International audienceThe aim of this experiment was to study the effect of feeding level (FL) on the digestibility of unconserved forage obtained from two permanent grasslands cut at three different dates during the first cycle of growth. Forage was offered to Texel sheep (wethers), at maintenance level and at ad libitum level. Differences in voluntary intake (VI) between grasslands were also tested. Organic matter digestibility (OMD) measured at ad libitum level and at VI was 13% higher on harvested forage from grassland rich in forbs (GRF) than grassland rich in grasses (GRG) at early herbage growth stages, but these differences were no longer found at later maturity stages. In GRF, there were no differences for OMD, at either FL at the young growth stages, but at the end of the cycle the OMD obtained at ad libitum level (0·56) was higher than that at maintenance level (0·50). However, in GRG, at an early stage of forage maturity, OMD at ad libitum level (0·67) was lower than that at maintenance level (0·70), but this difference was no longer found at the end of the growth cycle. In conclusion, the effect of FL on the digestibility of unconserved forage from permanent grasslands depends on the type of grassland. These differences are mainly explained by the different botanical composition of the grassland types

Cooperative localization based on range-only measurements from robots and infrastructure

International audienc

Near infrared reflectance spectroscopy to predict energy value of compound feeds for swine and ruminants

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Ruminal dry matter and nitrogen degradation in relation to condensed tannin and protein molecular structures in sainfoin (Onobrychis viciifolia) and lucerne (Medicago sativa).

Sainfoin is a temperate legume that contains condensed tannins (CT), i.e. polyphenols that are able to bind proteins and thus reduce protein degradation in the rumen. A reduction in protein degradation in the rumen can lead to a subsequent increase in amino acid flow to the small intestine. The effects of CT in the rumen and the intestine differ according to the amount and structure of CT and the nature of the protein molecular structure. The objective of the present study was to investigate the degradability in the rumen of three CT-containing sainfoin varieties and CT-free lucerne in relation to CT content and structure (mean degree of polymerization, proportion of prodelphinidins and cis-flavanol units) and protein structure (amide I and II bands, ratio of amide I-to-amide II, α-helix, β-sheet, ratio of α-helix-to-β-sheet). Protein molecular structures were identified using Fourier transform/infrared-attenuated total reflectance (FT/IR-ATR) spectroscopy. The in situ degradability of three sainfoin varieties (Ambra, Esparcette and Villahoz) was studied in 2008, during the first growth cycle at two harvest dates (P1 and P2, i.e. 5 May and 2 June, respectively) and at one date (P3) during the second growth cycle (2 June) and these were compared with a tannin-free legume, lucerne (Aubigny). Loss of dry matter (DMDeg) and nitrogen (NDeg) in polyester bags suspended in the rumen was measured using rumen-fistulated cows. The NDeg of lucerne compared with sainfoin was 0·80 v. 0·77 at P1, 0·78 v. 0·65 at P2 and 0·79 v. 0·70 at P3, respectively. NDeg was related to the rapidly disappearing fraction (‘a’) fraction (r=0·76), the rate of degradation (‘c’) (r=0·92), to the content (r=−0·81) and structure of CT. However, the relationship between NDeg and the slowly disappearing fraction (‘b’) was weak. There was a significant effect of date and species×date, for NDeg and ‘a’ fraction. The secondary protein structure varied with harvest date (species×date) and was correlated with the fraction ‘b’. Both tannin and protein structures influenced the NDeg degradation. CT content and structure were correlated to the ‘a’ fraction and to the ‘c’. Features of the protein molecular secondary structure were correlated to the ‘b’ fraction