Inthisthesiswefocusontheimpactofilluminationchangesinvideoand we discuss how we can minimize the impact of illumination variance in video processing systems. Identifyingandremovingshadowsautomaticallyisaverywellestablished and an important topic in image and video processing. Having shadowless image data would benefit many other systems such as video surveillance, tracking and object recognition algorithms. Anovelapproachtoautomaticallydetectandremoveshadowsispresented in this paper. This new method is based on the observation that, owing to the relative movement of the sun, the length and position of a shadow changes linearly over a relatively long period of time in outdoor environments,wecanconvenientlydistinguishashadowfromotherdark regions in an input video. Then we can identify the Reference Shadow as the one with the highest confidence of the mentioned linear changes. Once one shadow is detected, the rest of the shadow can also be identifiedandremoved. Wehaveprovidedmanyexperimentsandourmethod is fully capable of detecting and removing the shadows of stationary and moving objects. Additionally we have explained how reference shadows can be used to detect textures that reflect the light and shiny materials such as metal, glass and water. ...

Syfte: Syftet med denna studie var att jämföra Multilens Bilux Iris-glas mot deras vanliga polariserade filterglas på syncentralspatienter med uttalade bländningsbesvär. Metod: I studien undersöktes 15 personer mellan 42-89 år. Försökspersonerna som hade bokad tid hos Syncentralen i Kalmar fick valet att ställa upp på en studie där de skulle få testa ytterligare ett filterglas. Patienterna återkallades efter ett par veckor då synskärpetester gjordes i hög och lågkontrast med och utan bländningsbelysning. Undersökningen innefattade även en intervju under vilken patienten fick berätta vad han/hon tyckte om respektive glas. Resultat: Kontrast påverkade visus. Högkontrast visus påverkades inte nämnvärt med olika filterglasen eller bländning. För lågkontrast visus fanns heller ingen signifikant skillnad mellan filterglasen med eller utan bländning. En del patienter upplevde bättre synförhållanden med Bilux i vissa situationer. Slutsats: Högkontrast samt lågkontrast visus påverkades inte nämnvärt med de olika filterglasen eller med bländning. Subjektivt upplevdes förbättrade synförhållanden i vissa situationer med Bilux och vanliga filterglas. / The aim of this study was to compare Multilens Bilux Iris against their regular polarized filter-glasses on low vision subjects with pronounced light sensitivity. A total of 15 people aged 42-89 years participated in the study. All were patients at the low-vision clinic at the hospital in Kalmar, Sweden. Patients were recruited during a prior routine examination whereby they were asked if they would be willing to participate in a study in which they would have the chance to try an extra pair of filter-glasses. The patients were recalled after a few weeks for the examination. Patients’ high- and low contrast visual acuity was measured both with and without glare. An interview with all of the patients was also conducted regarding the different filter lenses. This study showed no significant difference in high contrast or low contrast visual acuity, with or without the different filters examined during this study. A subjective difference was however detected between filters under certain situations.

Thesis (M.S.)--Ohio University, June, 2003. / Title from PDF t.p. Includes bibliographical references (leaves 102-108).

Made available in DSpace on 2015-04-01T11:58:39Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 7033084 bytes, checksum: 063f29a23a1345b73488effdfec70d94 (MD5) Previous issue date: 2013-10-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Due to the densification of urban centers and the verticalization, the urban grid has been modified to the point of significantly affecting the availability of daylight in buildings. Under this view, the scope of this paper discusses the influence of variables around and of the building on the illuminance and glare of its indoor environments. From a case study in Manaíra, a district in the city of João Pessoa PB, the aspects which were evaluated as independent variables were: the degree of obstruction of the surroundings, the properties of the external vertical surfaces - reflectance and solar protection elements, the height of the floor and orientation. The dependent variables related to daylighting in indoor environments were: the illuminance distribution, the percentage of the illuminated area inserted into the useful range of illuminance and the occurrence of glare. Through computer simulation, by using the Daysim software, the use of dynamic metric allowed the extraction of data of the Useful Daylight Illuminance (UDI 300-3000lux), besides values in temporal and spatial scale in the period of a year corresponding to the weather file of the city mentioned. In addition, the ratios of Daylight Glare Probability (DGP) were found through the Evalglare program. It was possible, by the use of graphic and statistical methods, to find differences between the 120 models of indoor environments inserted in three different urban settings and to compare the research variables which showed the strongest influence. It was noticed that the sun protection devices in facades contributed most significantly to the useful frequency range of illuminance compared to scenarios without shading, being it paramount to the increase of lighting levels and the reduction of visual discomfort. Additionally, it was noticed that the most clogged pavements, like the ground, were the most uniform. However, there was a level of illuminance below the range of sufficiency (UDI <3000lux). Regarding the variables of the building, the facades which are oriented Northwest and Northeast have better performance, featuring environments with minor variations of illuminance, satisfactory percentage of illuminated area above 75% of UDI, as well as larger bands of unnoticeable glare. Differently, the Southwest facade recorded the worst results in respect of lighting levels and the Southeast facade is the most prone to the increase of glare probability, especially in embedded environments of scenarios with maximum reflection of the facades and in situations without interference from the surroundings and with the contribution of direct light. / Com o adensamento dos centros urbanos e a verticalização, a malha urbana vem sendo modificada a ponto de afetar significativamente a disponibilidade da luz natural nas edificações. Sob esta ótica, o escopo do presente trabalho aborda a influência das variáveis de entorno e do edifício sobre as iluminâncias e ofuscamento nos ambientes internos. A partir de um estudo de caso no Bairro de Manaíra na cidade de João Pessoa-PB, foram avaliadas como variáveis independentes: o grau de obstrução do entorno, as propriedades das superfícies verticais externas refletância e elementos de proteção solar, a altura do pavimento e a orientação. As variáveis dependentes, relacionadas com a iluminação natural nos ambientes internos, foram: a distribuição das iluminâncias, o percentual de área iluminada inseridas na faixa útil de iluminâncias e a ocorrência de ofuscamento. Por meio de simulação computacional, utilizando o software Daysim, o uso da métrica dinâmica permitiu extrair dados de iluminâncias natural útil (INU 300-3000lux), além de valores em escala temporal e espacial no período de um ano correspondente ao arquivo climático da cidade já mencionada. Em complemento, foram encontrados os índices da probabilidade de ofuscamento da luz natural (POLN) através do aplicativo Evalglare. Com métodos gráfico e estatístico, foi possível verificar diferenças entre os 120 modelos de ambientes internos inserido em três cenários urbanos distintos e comparar as variáveis de pesquisa que apresentaram maior influência. Percebeu-se que os dispositivos de proteção solar nas fachadas contribuíram mais significativamente para frequência das iluminâncias na faixa útil quando comparadas com os cenários sem sombreamento, sendo primordial para aumento dos níveis de iluminação e redução dos desconfortos visuais. Adicionalmente, notou-se que os pavimentos mais obstruídos, a exemplo do Térreo, foram os mais uniformes, porém com iluminâncias abaixo da faixa suficiente (INU <300lux). Quanto às variáveis do edifício, as fachadas orientadas para Noroeste e Nordeste apresentaram melhor desempenho, apresentando ambientes com menores variações das iluminâncias, percentuais satisfatórios de área iluminada acima de 75% de INU bem como maiores faixas de ofuscamento imperceptível. Diferentemente, a fachada Sudoeste registrou o pior resultado em relação aos níveis de iluminação e a Sudeste a mais propensa ao aumento da probabilidade de ofuscamento, sobretudo nos ambientes inseridos nos cenários com reflexão máxima das fachadas e em situações sem interferência do entorno, com a contribuição da luz direta.

Artificial lighting is an integral part of our everyday life. Nowadays, a large number of people spend practically all their productive time in the presence of the artificial lighting system. This places considerable demands on the quality of this artificial lighting system. One of the indicators of the quality of the lighting system is the evaluation of glare. The UGR evaluation methodology is currently used to evaluate glare. However, the UGR rating has its limitations. These limitations include ambiguous assessments of luminaires with non-uniform luminous surface (so - called non - uniform luminaires). This diploma thesis deals with the issue of discomfort glare of non-uniform luminaires. The aim is to make a literature review of this issue. The first part focuses on theoretical knowledge of glare and its evaluation. Another part is an analysis of recent studies on the topic about glare from non-uniform types of luminaires. The last chapters of the thesis deal with own practical evaluation of glare.

The dilemma of keeping the daylight quality and view to the outside or protecting our eyes from disturbing glare by covering the window is a moment that probably everyone has experienced in their life. Having access to daylight and enjoying the view to the outside when there is not visual comfort has been a problematic issue related to the window in space. Shading devices are designed in different shapes and forms to control glare and also energy consumption inside the space. Using shading covers part of the window and it affects the light quality and view to the outside and can change our perception from architectural space.In this thesis, the main question is how can we protect the indoor space from discomfort glare without covering the whole part of the window by curtain, blinds or shading devices in order to keep daylight quality and view to the outside.Glare is a phenomenon that is related to the viewpoint of observers and in order to study the glare metrics, the data from 140 viewpoints of the observer in 20 different locations in one simulated room were analyzed based on three main factors:1- Glare Metrics2- Light Quality3- ViewThe 20 selected patterns were simulated in [Rhino /Grasshopper/ Diva] software to analyze the glare and daylight metrics in Solstices and Equinoxes. Also, in order to define a parameter for view, one questionnaire was used and the responses from 40 participants were collected and all of the data were evaluated by mathematics and statistics methods.The final aim of the study is to introduce some simple principles for patterns of shadings to provide better-daylit environment and view to the outside with most visual comfort conditions for the user inside the space.

The main aim of this thesis was to evaluate the performance of the contrast sensitivity clock (CSC), a new screening device for measuring contrast sensitivity (CS) and glare. This device allows CS without glare, with glare and disability glare scores to be recorded. After initial data collection the design of the CSC was slightly amended improving the performance of the device. The amended design of the CSC was shown to be a valid, discriminative and repeatable measure for purpose. The CSC is also a quick test to perform and is relatively cheap to produce. If all these factors are considered it shows potential to become the test of choice for the assessment of visual glare. A head-mounted display system was also evaluated in terms of the glare effects it may cause. The monocular display screen of the device significantly reduced the CS of the eye directly exposed but also had an effect on binocular performance, reducing amounts of binocular summation. Electronic devices, including head-mounted displays and satellite navigation systems can seriously affect CS at low luminance levels, similar to those found when driving at night.

This master’s thesis presents new tendency in automotive lighting – matrix LED headlamp. This thesis consists of description of matrix headlamp construction, main functions of matrix headlamp and controlling by using new integrated circuit, developed by ON Semiconductor Company. The aim of this project is concept of algorithm, which provides correct function of integrated circuit. A part of this thesis is to develop and assembly evaluation kit with this integrated circuit, which will be use to present integrated circuit for customers.

Cette thèse vise à contribuer à la caractérisation, à l’aide de modélisation et d’expérience, de la dynamique de bulle en microfluidique. Deux régimes d’écoulements rencontrés en microfluidique sont étudiés, le régime bubbly flow et le régime Taylor flow. En particulier, la première partie de cette thèse traite de la dynamique d’un écoulement de type bubbly flow dans un microcanal rectiligne de section circulaire en présence de surfactants. Le code de calcul numérique JADIM est utilisé. Une méthode numérique permettant, d’une part, de simuler le transport de surfactants le long d’une interface qui bouge et qui se déforme, et d’autre part, de simuler l’effet Marangoni crée par une distribution inhomogène de ces surfactants sur cette interface, est implémentée et validée. Les simulations effectuées avec ce code concernant la dynamique d’un écoulement de type bubbly flow montrent par exemple que, le confinement créé par les parois du microcanal résulte en une distribution des surfactants sur la surface des bulles qui est fondamentalement différente d’une distribution rencontrée dans le cas d’une bulle qui se déplace dans un liquide de dimension infinie. En effet, les surfactants s’accumulent en des locations spécifiques sur la surface des bulles et créent des forces de Marangoni locale, qui influencent drastiquement la dynamique des bulles. Dans certains cas, les surfactants peuvent même engendrer une désintégration de la bulle, un mécanisme qui est rationalisé par un bilan de force à l’arrière de la bulle. La méthode numérique implémentée dans cette thèse est également utilisée pour un problème pratique concernant la production artisanale de Mezcal, une boisson alcoolisée produite au Méxique. La seconde partie de cette thèse traite de la dynamique d’un écoulement de type Taylor flow, à l’aide d’expérience et de modélisation. Une méthode expérimentale permettant de mesurer l’épaisseur du film de lubrification qui se forme entre une bulle de Taylor et les parois du microcanal est développée. Cette méthode requiert uniquement une image « brightfield » de la bulle. En plus de la mesure de l'epaisseur du film de lubrification, la méthode permet aussi de mesurer la profondeur du microcannal. Enfin, l'utilisation de la méthode proposée couplée à la mesure de la vitesse de translation de la bulle permet de déduire la tension de surface de celle-ci. Dans le dernier chapitre de cette thèse, l'influence des effets gravitaires sur la dynamique des écoulements de Taylor est quantifiée. Quoique souvent négligée en microfluidique, il est montré que les effets gravitaires peuvent avoir un impact significatif sur la dynamique des écoulements de Taylor. Ces impacts sont quantifiés à l'aide d'expériences et de modélisations. Ce travail a été réalisé à la Princeton University avec Professeur Howard A. Stone pendant un séjour de 7 mois. / This thesis aims at contributing to the characterization of the dynamics of bubbles in microfluidics through modeling and experiments. Two flow regimes encountered in microfluidics are studied, namely, the bubbly flow regime and the Taylor flow regime (or slug flow). In particular, the first part of this thesis focuses on the dynamics of a bubbly flow inside a horizontal, cylindrical microchannel in the presence of surfactants using numerical simulations. A numerical method allowing to simulate the transport of surfactants along a moving and deforming interface and the Marangoni stresses created by an inhomogeneous distribution of these surfactants on this interface is implemented in the Level set module of the research code. The simulations performed with this code regarding the dynamics of a bubbly flow give insights into the complexity of the coupling of the different phenomena controlling the dynamics of the studied system. Fo example it shows that the confinement imposed by the microchannel walls results in a significantly different distribution of surfactants on the bubble surface, when compared to a bubble rising in a liquid of infinite extent. Indeed, surfactants accumulate on specific locations on the bubble surface, and create local Marangoni stresses, that drastically influence the dynamics of the bubble. In some cases, the presence of surfactants can even cause the bubble to burst, a mechanism that is rationalized through a normal stress balance at the back of the bubble. The numerical method implemented in this thesis is also used for a practical problem, regarding the artisanal production of Mezcal, an alcoholic beverage from Mexico. The second part of the thesis deals with the dynamics of a Taylor flow regime, through experiments and analytical modeling. An experimental technique that allows to measure the thickness of the lubrication film forming between a pancake-like bubble and the microchannel wall is developed. The method requires only a single instantaneous bright-field image of a pancake-like bubble translating inside a microchannel. In addition to measuring the thickness of the lubrication film, the method also allows to measure the depth of a microchannel. Using the proposed method together with the measurment of the bubble velocity allows to infer the surface tension of the interface between the liquid and the gas. In the last chapter of this thesis, the effect of buoyancy on the dynamics of a Taylor flow is quantified. Though often neglected in microfluidics, it is shown that buoyancy effects can have a significant impact on the thickness of the lubrication film and consequently on the dynamics of the Taylor flow. These effects are quantified using experiments and analytical modeling. This work was performed at Princeton University with Professor Howard A. Stone during a seven month stay.

The theme of this master’s thesis is the real-time rendering of glare as seen through human eyes, as a post-processing effect applied to a first-person view in a 3D application. Several techniques already exist, and the basis for this project is a paper from 2009 titled Temporal Glare: Real-Time Dynamic Simulation of the Scattering in the Human Eye, by Ritschel et al. The goal of my project was initially to implement that paper as part of a larger project, but it turned out that there might be some opportunities to build upon aspects of the techniques described in Temporal Glare; in consequence these various opportunities have been explored and constitute the main substance of this project. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>