OBJECTIVE: This case series evaluated the vision and refractive outcomes of patients who underwent Raindrop corneal inlay removal with or without concomitant LASIK treatment. METHODS: This study utilized a case series design and a retrospective data review of electronic medical records from a private ophthalmology clinic in Boston, MA. Twenty-one patients who had a Raindrop inlay placed and subsequently removed were identified. To be included in the study, patient records had to contain vision and refraction measurements from (1) before Raindrop inlay placement, (2) before Raindrop inlay removal, and (3) at least 1 month after Raindrop inlay removal. Fifteen patients with the necessary records were included in the study. Of these 15 patients, 7 had Raindrop inlays removed and the remaining 8 had Raindrop inlays removed with concomitant LASIK treatment. RESULTS: Fourteen of the 15 total patients had a best-corrected distance vision of 20/20 or better prior to inlay placement. This study found that 10 of these 15 patients experienced a loss of at least 1 line of best-corrected distance vision by the time of inlay removal. Inlay removal was performed at a mean of 523 days, or approximately 17 months, after placement. Even after inlay removal (>6 weeks), 7 patients continued to sustain a loss of 1 or more lines of best-corrected distance vision. In patients receiving LASIK at or after the time of inlay removal, the refractive outcome was close to target in only one case. CONCLUSION: After Raindrop inlay removal, many patients experience an improvement in their vision compared with pre-explantation; however, their best-corrected distance vision may not immediately return to preoperative values. Corneal haze and inflammation may continue to persist post-explantation and affect measurements of refractive error. Concomitant LASIK treatment upon inlay removal may therefore fail to achieve the intended result of monovision as an alternative treatment for presbyopia.

L'utilisation d'algorithmes de vision permettrait d'élargir le domaine d'application des systèmes d'aide à la conduite à d'autres situations telles que : les scènes urbaines ou les conditions météorologiques dégradées. À cette fin, trois nouvelles applications sont étudiées dans cette thèse pour la pluie et les feux tricolores. La pluie est la condition météorologique dégradée la plus fréquente. Nous comparons les modèles physiques et photométriques existants pour la pluie et les gouttes de pluie. Lors d'une conduite en temps de pluie de jour, les gouttes sur le pare-brise diminuent considérablement la visibilité du conducteur. Lorsqu'elles sont vue par une camera embarquée standard celles-ci apparaissent défocalisées. Ainsi, nous proposons de détecter ces gouttes hors-focus en utilisant soit une approche par manque de gradients soit par l'évaluation locale du flou. Lors d'une conduite de nuit sous la pluie, ce sont les phares qui paradoxalement diminuent la visibilité car leur lumière est réfléchie par les gouttes vers le conducteur. Nous appuyant sur la conception d'un simulateur physique, nous proposons un éclairage adaptatif qui illuminerait la scène sans éclairer les gouttes qui tombent. Les résultats de notre simulateur et le premier prototype construit montre que l'idée avancée pourrait efficacement améliorer la visibilité générale d'une scène. D'autre part, nous étudions la détection et le suivi de gouttes de pluie à grande vitesse. Les feux tricolores ont un rôle crucial dans la compréhension des scènes urbaines. Bien qu'il existe déjà des systèmes de détection de feux tricolores, les algorithmes actuels ne fonctionnent que dans des conditions simples. Ainsi, nous avons développé un algorithme de détection de feux tricolores qui utilise une détection en niveau de gris des spots lumineux et une classification par reconnaissance de modèle. L'approche ainsi conçue est assez flexible pour détecter différents types de feux tricolores même avec une camera à faible dynamique. Notre proposition a été évaluée sur des séquences acquises en France, Chine et Suisse. / Vision algorithms can be used to expand the working range of the assistance systems so as to deal with urban scenes or degraded weathers. To this end, three novel applications are investigated in this thesis for both rain and traffic lights. Rain is the most frequent degraded weather condition. We review the various physics and photometry models for rain and raindrops, and highlight some of the misuses. When driving in daytime the raindrops on the windscreen lower the driver visibility. For standard on-board camera these drops appear as unfocused. Hence, we investigate the detection of unfocused raindrops using blur maps or lack of gradients with photometry. For nightime driving in rain, the headlights paradoxically reduce the visibility due to light reflected off of raindrops back toward the driver. Relying on a physic-based simulator, we propose to build an illumination device that would illuminate the scene without shining the falling particles. The performance of the simulator and a proof-of-concept prototype sustain that our idea can efficiently improve the overall scene visibility. Fast reactive drops detection and tracking is also investigated.To deal with urban scenes, traffic lights play a key role. Though traffic light recognition was attempted in the past, the existing algorithms can't handle complex scenarios. Hence, we have developed a traffic light recognition algorithm that uses a grayscale spot light detection and a template matching classification. Our approach is modular and capable of detecting various kind of traffic lights even when using a low-dynamic camera. We have evaluated our algorithm on sequences from France, China and Switzerland.

Cette étude propose une unification des formulations mono- et multi-moments de la distribution granulométrique des pluies (DSD pour « drop size distribution ») proposées dans la littérature dans le cadre des techniques de mise à l’échelle (scaling). On considère dans un premier temps que la DSD normalisée par la concentration en gouttes (Nt, moment d'ordre 0 de la DSD) peut s’écrire comme une fonction de densité de probabilité (ddp) du diamètre normalisé par un diamètre caractéristique (Dc). Cette ddp, notée g(x) avec x=D/Dc, aussi appelé distribution générale, semble être bien représentée par une loi gamma à deux paramètres. Le choix d’un diamètre caractéristique particulier, le rapport des moments d’ordre 4 et 3, conduit à une relation d’auto-consistance entre les paramètres de la fonction g(x). Deux méthodes différentes, fondées sur 3 moments particuliers de la DSD (M0, M3 et M4) ou bien sur des moments multiples (de M0 à M6) sont proposées pour l’estimation des paramètres et ensuite évaluées sur 3 ans d’observations de DSD recueillies à Alès dans le cadre de l'Observatoire Hydrométéorologique Méditerranéen Cévennes-Vivarais (OHMCV). Les résultats révèlent que: 1) les deux méthodes d’estimation des paramètres ont des performances équivalentes; 2) malgré la normalisation, une grande variabilité de la DSD est toujours observée dans le jeu de données mis à l’échelle. Ce dernier point semble résulter de la diversité des processus micro-physiques qui conditionnent la forme de la DSD.Cette formulation est ensuite adaptée pour une mise à l’échelle avec un ou deux moments de la DSD en introduisant des modèles en loi puissance entre des moments dits de référence (par exemple l’intensité de la pluie R et / ou le facteur de réflectivité radar Z) et les moments expliqués (concentration en gouttes Nt, diamètre caractéristique Dc). De manière analogue à la première partie du travail, deux méthodes sont proposées pour estimer des paramètres climatologiques des DSD mises à l’échelle par un ou deux DSD moment(s). Les résultats montrent que: 1) la méthode d'estimation a un impact significatif pour la formulation de mise à l'échelle par un seul moment; 2) le choix du moment de référence dépend des objectifs d’étude: par exemple, le modèle mis à l'échelle par des moments d'ordre élevé produit une bonne performance pour les grosses gouttes mais pas pour les petites; 3) l’utilisation de deux moments au lieu d’un seul améliore significativement la performance du modèle pour représenter les DSD.Notre modèle est ensuite appliqué pour analyser la variabilité inter- événementielle selon trois paramètres (Nt, Dc et μ, ce dernier paramètre µ décrivant la forme de la fonction gamma). Différentes séquences de pluie ont été identifiées de façon subjective pour l’événement pluvieux intense des 21-22 octobre 2008 par des changements brusques des moments et/ou paramètres dans les séries temporelles correspondantes. Ces phases de pluie sont liées à des processus météorologiques différents. Une relation préliminaire est établie entre les observations radar et la variation des paramètres des DSD au sol telle que mesurée par le disdromètre. Les formulations de mise à l’échelle sont également appliquées pour des estimations des densités de flux d’énergie cinétique des précipitations à partir de l'intensité de la pluie et / ou de la réflectivité radar. Les résultats confirment que l’utilisation de deux moments (R et Z) améliore significativement les performances de ces modèles, malgré les caractéristiques d'échantillonnage très différentes des radars et des pluviomètres. Cette application ouvre des perspectives intéressantes pour la spatialisation de l’énergie cinétique des pluies dans le cadre des études sur le pouvoir érosif des pluies. / This study offers a unified formulation for the single- and multi-moment raindrop size distributions (DSD), which were proposed in the framework of scaling analysis in the literature. The key point is to consider the DSD scaled by drop concentration (Nt, 0th order DSD moment), as a probability density function (pdf) of raindrop diameter scaled by characteristic diameter (D/Dc). The Dc is defined as the ratio of the 4th to the 3rd DSD moment. A two-parameter gamma pdf model, with a self-consistency relationship, is found to be suitable for representing the scaling DSD formulation. For the purpose of parameter estimation, two different methods, based on three DSD moments (0th, 3rd and 4th moments) and multiple DSD moments (from 0th to 6th moments), are proposed and then evaluated through the 3-year DSD observations, collected at Alés within the activities of the Cévennes-Vivarais Mediterranean Hydrometeorological Observatory (CVMHO). The results reveal that: 1) the scaled DSD model parameterized by three moments (0th, 3rd and 4th moments) possesses a similar performance compared to that constructed by multiple DSD moments; 2) regardless the application of scaled technique, large variation is still exhibited in this climatological DSD scaled dataset. The scaled DSD formulation is, in a second step, adapted to the one- and two-moment scaling DSD formulations by introducing single and dual power-law models between the reference moments (e.g. rain rate R and/or radar reflectivity factor Z) and the explained moments (total concentration Nt, characteristic diameter Dc). Compared with previous DSD formulations presented in the literature, the presented approach explicitly accounts for the prefactors of the power-law models to produce a uniform and dimensionless scaled distribution, whatever the reference moment(s) considered. In the same manner, two methods based on 1) single or dual power-law models and 2) multiple DSD moments (from 0th to 6th moments), are proposed to estimate the climatological parameters in the one- and two-moment scaling DSD formulations. The results show that: 1) the estimation method has a significant impact on the climatological DSD formulation scaled by one moment; 2) the choice of the reference moment to scale DSD depends on the objectives of the research: e.g. the DSD model scaled by high order moment produces a good performance for large drops at the cost of a poor performance for the small ones; 3) using two scaling moments improves significantly the model performance to represent the natural DSD, compared to the one-moment DSD formulation. In terms of applications of scaling DSD model, the analysis of the inter-event variability is performed on the basis of the scaling formulation containing three parameters (Nt, Dc and µ describing the shape of the gamma function). Different rain phases can be identified by the sudden shifts of moments and parameters in DSD time series. It is found that these rain phases are well linked to different weather processes. And a preliminary relationship is established between the radar observations and DSD parameters. The climatological scaling DSD formulations are also used for the DSD reconstitutions and for rainfall kinetic energy flux density estimations by rain intensity and/or radar reflectivity factor. The results confirm that the application of two scaling moments (R and Z) improves significantly the performance of these models, regardless the different sampling characteristics between radar and raingauge.

Aggregate breakdown is an important process controlling the availability of fine soil material necessary for structural sealing of soil surfaces under rainfall. It may be caused by slaking resulting from rapid soil wetting and by physical dispersion resulting from direct and indirect energetic raindrop impacts. Relationships have been proposed by others predicting steady infiltration rate and saturated hydraulic conductivity from final aggregate size following high energy rainfall on initially dry, uncovered soil surfaces. Under these extreme conditions, both rapid wetting and energetic raindrop impact result in maximum aggregate breakdown and surface sealing. Knowledge of the relative importance of these two agents under less severe conditions and knowledge of how increased aggregate stability due to conservative soil management may ameliorate them should improve prediction and management of aggregate breakdown and surface sealing. ¶ This study has isolated and quantified effects of rapid soil wetting and energetic raindrop impact on aggregate breakdown and surface sealing. Simulated rainfall was applied to re-packed soils from differing tillage treatments on light textured soils from near Cowra and Condobolin in New South Wales, Australia. Aggregate breakdown was assessed using aggregate size distribution, determined by wet sieving and summarised by a range of statistics. The degree of breakdown was assessed after 66 mm of simulated rainfall whilst the rate of change in aggregate size distribution was assessed by sampling after 5, 10, 15, 30 and 60 mm. The degree of surface sealing was assessed using final surface hydraulic conductivity after 66 mm rainfall calculated from inferred infiltration and measured sub-seal soil water potential. The rate of surface sealing was assessed prior to ponding using cumulative rainfall volume at ponding and throughout the post-ponding phase by decline in surface hydraulic conductivity as a function of cumulative rainfall kinetic energy. Two levels of raindrop kinetic energy flux and three wetting treatments were used to isolate effects of these agents of aggregate breakdown and surface sealing. ¶ Significant surface aggregate breakdown was observed when either rapid soil wetting or highly energetic raindrop impact were allowed to occur. The majority of the data suggest a negative interaction between the two agents. When soil was initially dry rapid soil wetting was the dominant agent causing rapid aggregate breakdown, generally within the first 5 mm of rainfall. When rapid soil wetting was prevented by tension pre-wetting, energetic raindrop impact was the dominant agent and was able to cause aggregate breakdown of an almost equivalent degree. This breakdown occurred over a period lasting for up to 30 mm of rainfall. In contrast, the rate and degree of surface sealing were influenced primarily by raindrop kinetic energy with highly energetic impact leading to significant surface sealing, irrespective of soil wetting. For the soils studied, it was concluded that structural sealing of surface soil, could be significantly reduced by protecting the soil surface from energetic raindrop impact but that prevention of surface aggregate breakdown required amelioration of both processes. ¶ In addition to the negative interaction referred to above, a positive interaction was observed whereby energetic raindrop impact occurring concurrently with rapid soil wetting caused a greater degree of aggregate breakdown and a greater degree of surface sealing than energetic raindrop impact occurring subsequent to rapid soil wetting. The effect on surface sealing may be explained by the effect of lower sub-seal water potential that necessarily results from initially dry soil condition required for concurrent rapid wetting. However, the effect on aggregate breakdown remains unexplained. ¶ Notwithstanding the above, permeability was reduced under high kinetic energy rainfall even when soil wetting was reduced to very slow rates by tension pre-wetting. Likewise, surface sealing did occur under low kinetic energy rainfall for the least stable soil following rapid soil wetting. It was concluded that threshold soil wetting rates and threshold rainfall energy levels, proposed by others, are either not applicable to these soils or are negligible. ¶ The rate and degree of aggregate breakdown was also dependent on the soil with the Cowra soil being more stable than the Condobolin soil. Greater aggregate stability brought about by conservative tillage treatments at both soil locations retarded and reduced surface sealing. Unvalidated simulation modelling was used to illustrate possible effects for the soil water balance. In contrast to the conclusions of Loch (1994b), that were based on soils throughout eastern Queensland, the soil water balance simulations predicted that the residual benefits in ameliorating surface sealing resulting from improved aggregate stability could significantly reduce point runoff under the lower intensity winter rainfalls experienced in southern New South Wales. ¶ Limited testing with Condobolin soil following tension pre-wetting showed that rainfall intensity, varying over the range from 16.5 to 66 mm h-1, had little effect on the decline in surface hydraulic conductivity as a function of cumulative rainfall kinetic energy. This contrasts with greater seal permeability under higher rainfall intensities observed by Romkens et al. (1985) and others. It is proposed that an alternative explanation exists for the observations of Romkens et al. based on reduction in seal permeability due to lower sub-seal water potential under lower intensity rainfall. ¶ Post-ponding reduction in K[subscript sat] under high kinetic energy rainfall exhibited exponential decline as a function of cumulative raindrop kinetic energy as proposed by Moore (1981b). However, inferred rates of decline prior to ponding were more rapid than measured post-ponding rates suggesting that infiltration models using only a single exponential rate of surface K[subscript sat] decline based on post-ponding measurements may be in error. Potential for error is greatest at early times for loose soil that is highly susceptible to sealing. ¶ Pre-ponding decline in surface aggregation was also relatively more rapid than post-ponding decline. This discrepancy was evident irrespective of soil pre-wetting. From this it was concluded that the more rapid initial aggregate breakdown and surface sealing was due, at least in part, to processes other than aggregate slaking due to rapid soil wetting. An explanation has been proposed as follows. Raindrops initially fall on aggregates that have not been subjected to rainfall and therefore each drop has the capacity to cause greater aggregate breakdown than subsequent raindrops that fall on aggregates or soil fragments that have been strong enough to survive preceding rainfall impacts. Such a mechanism could provide an alternative explanation of the findings of Baumhardt et al. (1991) who found that less cumulative raindrop kinetic energy was necessary to achieve a given reduction in surface conductance when the cumulative energy was supplied through lower energy drops. ¶ Relationships predicting rates of surface sealing using aggregate breakdown under rainfall and aggregate stability were evaluated. Post-ponding infiltration rate and surface K[subscript sat] were related to aggregate size by exponential functions. The proportion of surface aggregates less than 0.125 mm in diameter provided slightly more consistent relationships. Parameters of fitted relationships differed among wetting pre-treatments suggesting that the influence of sub-seal water potential on surface K[subscript sat] must be considered whenever such relationships are developed or applied. Aggregate stability determined by wet sieving was related to rainfall volume required for ponding, final K[subscript sat] and final aggregate size but only for initially dry soil suggesting that such relationships may be unique to the rainfall, soils and flow conditions used to develop them. ¶ This study has established the relative importance of rapid soil wetting and energetic raindrop impact in both aggregate breakdown and surface sealing over a range of antecedent soil water and rainfall conditions. It has quantified the effectiveness of culturally induced aggregate stability in ameliorating effects of these two important agents and illustrated the potentially significant consequences for the soil water balance. It has quantified temporal patterns of surface sealing and aggregate breakdown and proposed an alternative mechanism explaining more rapid aggregate breakdown during the initial stages of rainfall. It has identified possible explanations for effects of rainfall intensity on surface sealing observed in other studies. It has also partially evaluated a mechanism proposed to explain important effects of subseal water potential on seal permeability found in this and other studies. These significant findings have been used with the findings of other studies to amend the conceptual model proposed by Le Bissonnias (1990). The amended model gives a more complete description of the relationships between parameters and processes determining aggregate breakdown and structural surface sealing under rainfall.

Major portion of hurricane-induced economic loss originates from damages to building structures. The damages on building structures are typically grouped into three main categories: exterior, interior, and contents damage. Although the latter two types of damages, in most cases, cause more than 50% of the total loss, little has been done to investigate the physical damage process and unveil the interdependence of interior damage parameters. Building interior and contents damages are mainly due to wind-driven rain (WDR) intrusion through building envelope defects, breaches, and other functional openings. The limitation of research works and subsequent knowledge gaps, are in most part due to the complexity of damage phenomena during hurricanes and lack of established measurement methodologies to quantify rainwater intrusion. This dissertation focuses on devising methodologies for large-scale experimental simulation of tropical cyclone WDR and measurements of rainwater intrusion to acquire benchmark test-based data for the development of hurricane-induced building interior and contents damage model. Target WDR parameters derived from tropical cyclone rainfall data were used to simulate the WDR characteristics at the Wall of Wind (WOW) facility. The proposed WDR simulation methodology presents detailed procedures for selection of type and number of nozzles formulated based on tropical cyclone WDR study. The simulated WDR was later used to experimentally investigate the mechanisms of rainwater deposition/intrusion in buildings. Test-based dataset of two rainwater intrusion parameters that quantify the distribution of direct impinging raindrops and surface runoff rainwater over building surface — rain admittance factor (RAF) and surface runoff coefficient (SRC), respectively — were developed using common shapes of low-rise buildings. The dataset was applied to a newly formulated WDR estimation model to predict the volume of rainwater ingress through envelope openings such as wall and roof deck breaches and window sill cracks. The validation of the new model using experimental data indicated reasonable estimation of rainwater ingress through envelope defects and breaches during tropical cyclones. The WDR estimation model and experimental dataset of WDR parameters developed in this dissertation work can be used to enhance the prediction capabilities of existing interior damage models such as the Florida Public Hurricane Loss Model (FPHLM).