Dans le domaine moléculaire, les polymères sont observés et étudiés par microscopie. Les formes obtenues sont souvent imprécises en raison de l'effet de convolution et de diffraction de l'acquisition par microscopie. Par conséquent, le polymère apparait comme une courbe épaisse, bruitée et floue. Pour étudier les caractéristiques d'une chaîne de polymère, une des approches possibles consiste à réduire la forme acquise par microscope à une représentation minimale, soit une courbe. Cette dernière doit représenter au mieux l'objet étudié malgré les différentes difficultés rencontrées telles que la qualité des images ou les imprécisions dues à la discrétisation. De plus, un polymère adopte un mouvement "Reptilien" et peut former des géométries complexes telles que des courbes fermées ou avec boucles. L'objet de cette thèse est donc l'extraction de courbes visant à fournir une représentation minimale des polymères à des fins d'analyse. La méthode que nous proposons comprend deux grandes étapes à savoir : L'extraction des géodésiques et leur fusion. La première étape consiste à calculer un ensemble de géodésiques, chacune parcourant une partie distincte de la forme. Ces morceaux de géodésiques sont fusionnés dans la seconde étape afin de générer la courbe complète. Afin de représenter la reptation, les géodésiques doivent être fusionnées dans un ordre précis. Nous modélisons ce problème par graphes et nous cherchons l'ordre de fusion en parcourant le graphe. La fusion est effectuée selon le chemin optimal minimisant différentes contraintes. / In the molecular field, polymers are observed and studied by microscopy. The shapes obtained are often inaccurate because of the convolution and diffraction effect of microscopy. Therefore, the polymer appears as a thick, noisy and fuzzy curve. In order to study a polymer chain, one of the possible approaches consists in reducing the acquired shape to a minimal representation, ie a curve. This curve must represent the studied object in the best way, despite the various encountered difficulties, such as the quality of the images or inaccuracies due to discretization. In addition, a polymer performs a "Reptilian" movement and can form complex geometries such as closed and looped curves. The object of this thesis is, therefore, the extraction of curves aimed at providing a minimal representation of the polymers for analysis. The proposed method comprises two major steps: geodesics extraction and their fusion. The first step is to compute a set of geodesics, each one traversing a distinct part of the shape. These pieces of geodesics are fused in the second step to generate the complete curve. In order to represent the reptation, the geodesics have to be merged in a precise order. We model this problem by graphs and consider the fusion as a graph traversal problem. The fusion is performed according to the optimal path minimizing various constraints.

This masters thesis is focused around the comparison of time dependent video grayscale conversion methods based on a user experiment. The test methodology is based on the pairwise comparison method 2AFC. It is composed of two test variants: a test with a reference video and a test without a reference video. The coefficients of agreement, consistency and correlation are utilized in the result analysis. The testing was done on 60 subjects which have done 7200 pairwise comparisons. The test results show that the time dependent method Hu14 is the most universal. Time dependent method Kim09 was bested by some non-dependent methods. The results also indicate that there is some correlation between the two test variants and that the choice of the input video can have impact on the method performance. The main contribution of this thesis is that non-dependent methods can under certain circumstances rival the performance of dependent methods and that the addition of a reference video did not have a meaningful impact on the test subjects judgements.

Grayscale pictures were never replaced by color ones and will probably never be, because they are indispensable in many areas. In this thesis was chosen three methods for color-to-gray conversion. These methods was implemented afterwards. Within this thesis was also made test set of 24 HDR pictures, which was together with existing set of 24 LDR pictures used to test and evaluate features of implemented methods. These methods were also compared from the point of accurancy and preference using questionnaire.

The global average screen time on smartphones reaches up to 4 hours, revealed App Annie. In recent years, there have also been increasing concerns about the problematic use of smartphones and its impact on public health, such as sleep hygiene, cognitive capacity, and mental health. According to Tristan Harris, a former Design Ethicist at Google, enabling grayscale is a possible way to reduce screen time, because it makes the smartphone less attractive. Therefore, the aim of this thesis is to perform an experiment to confirm or reject the functionality of this recommendation and at the same time, through in-depth interviews with its participants, to describe how they perceive it and how it affects them.

This thesis deals with grayscale e-beam lithography and diffractive optical elements fabrication. Three topics are addressed. The first topic is combined grayscale e-beam lithography. The goal of this task is combining exposures performed by two systems with various beam energies. This combined technique leads to a better usage of both systems because various structures can be more easily prepared by one electron beam energy than by the other. The next topic is the optimization of shape borders of exposing structures that are defined by image input. The influence of such optimization on exposure data preparation is evaluated, as well as the exposure time and the change of optical properties of testing structures. The possibility of deep multilevel diffractive optical element fabrication in plexiglass blocks is researched as the third topic. Plexiglass can replace the system of a resist and a substrate. A new approach to writing down the structures by electron beam is presented, minimizing thermal stress on the plexiglass block during the exposure. The writing method also improves the homogeneity of exposed motifs. A method for computing the exposure dose for specific multilevel structures was designed. This method is based on the existing model of proximity effect computation and it minimizes the computing time necessary to obtain the exposure doses.

Les structures optiques diffractives sous forme d’hologramme de sécurité sont largement employées contre la falsification et la contrefaçon.Elles sont présentent sur les billets de banque, les documents de voyage et d’identité, etc. Leurs techniques de fabrication sont de plus en plus accessibles, augmentant les risques de fraudes et la concurrence sur le marché des hologrammes de sécurité. Pour endiguer les fraudes et gagner des parts de marché, il faut innover. Ces travaux de thèse de doctorat s’articulent autour du développement de structures optiques diffractives multiéchelles innovantes. Ces structures diffractives multiéchelles sont la combinaison de structures diffractives microscopiques permettant la mise en forme de la lumière incidente avecdes structures nanoscopiques qui permettent la création d’effets colorés. Ces travaux accordent une grande place au développement de la technique de photolithographie multiniveaux par écriture directe massivement parallèle. Ils abordent également le développement d’un modèle hybride permettant de simuler physiquement le comportement des structures diffractives (notamment de nos structures multiéchelles) en temps réel. Ce rendu en temps réel est possible grâce à l’utilisation du processeur graphique (GPU) au travers d’OpenGL et des programmes Shader, ainsi qu’avec l’utilisation de données précalculées. Le développement de ces structures multiéchelles permet la création et la commercialisation de nombreux nouveaux effets visuels, ce qui participe aux doubles objectifs de contrer les fraudes et de gagner en part de marché. / Diffractive optical structures on the fon of security holograms are widely used against forgery and counterfeiting. They are present on banknotes, travel and identity documents, etc. Their manufacturing techniques are becoming more and more accessible, increasing the risk of fraud and competition in the security hologram market. To stem fraud and gain marketshare, hologram procedures must innovate continously. This Ph.d focuses on the developmentof innovative multi-scale diffractive optical structures. These multi-scale diffractive structures result from combination of microscopic diffractive structures that shape the incident light and nanoscopic structures that generate colored effects. This work places emphasis on the development of the massively parallel-direct-write greyscale photolithography fabrication process. We also discuss the development of an hybrid model for physically simulating the behaviour of diffractive structures (especially our multiscale structures) in real time. This real time rendering is possible thanks to the use of the graphical processor unit (GPU) through OpenGL and Shader programs, as well as the use of precomputed data. The development of these multiscale structures has led to the creation and commercialisation of many new visual effects and contributed to the dual objectives of counter fraud and gain market share.

This work presents a new extension for Uniform Marker Field, which is able to detect UMF on the cylinder. First part of the text deals with Augmented reality and focuses on systems using markers. It discusses the actual state-of-the-art systems and its possibilities. After that it focuses more deeply on the marker system Uniform marker field and its grayscale variants. Next part of the work describes properties of the cylinder projected in real space. Important properties for detecting are discussed in detail. Then the proposal and description of detection algorithm is presented. Implementation of algorithm is tested and evaluated on the very end of this thesis.

[pt] Ao identificar o objeto da disciplina do design gráfico como o espaço gráfico de leitura, e sua condição mais específica na experiência de tornar visíveis as palavras e as idéias, reconhecemos do ponto de vista do leitor que todas as formas derivadas do uso do Desenho e escrita, adquirem sentido nesse espaço como consequência do poder universal de suas conexões. Nesta perspectiva, identificamos que o objeto desta pesquisa é o processo de transferência de conhecimento gráfico que ocorre durante a segunda metade do século XV no contexto da implementação da imprensa. Isso envolve considerar, como tipógrafos e gravadores fazem a transição da tradição do Manuscrito iluminado da Idade Média para o advento da imprensa. Esta tese está focada no campo da abstração de cores que leva a compreender o caráter estrutural que adquire a escala de cinza no espaço gráfico, como consequência do consenso quanto à falta de uso de cores no livro impresso. Assim, o objetivo desta pesquisa é mostrar a relevância da luminosidade no espaço gráfico, considerando especialmente a comparação entre o caráter acromático da gravura e o aspecto inacabado do texto literário referido ao ato de leitura. A observação dos aspectos geométricos, cromáticos e caligráficos neste contexto permite atribuir a particularidade dessa abstração a uma compreensão cultural da correspondência entre a escala de cinza e a luminosidade das cores. Tudo isso na invenção conjunta de gravura e tipografia. / [en] By identifying the object of the discipline of graphic design as the graphic space of reading and its more specific condition in the experience of making words and ideas visible, we recognize from the point of view of the reader, that all forms derived from the use of the Drawing and writing acquire meaning in that space, as a consequence of the universal power of their connections. From this, we identify that the object of this research is the process of transfer of graphic knowledge that occurs during the second half of the 15th century in the context of the implementation of the printing press. This involves considering how typographers and engravers make the transition from the tradition of the illuminated Manuscript of the Middle Ages to the advent of the printing press. This thesis is focused on the field of abstraction of colors that leads to understand the structural character that acquires the gray scale in the graphic space, as a consequence of the consensus regarding the lack of use of colors in the printed book. Thus, the aim of this research is to show the relevance of the luminosity in graphic space, considering especially the comparison between the achromatic character of the engraving and the unfinished aspect of the literary text referred to the act of reading. The observation of the geometric, chromatic and calligraphic aspects in this context, allow us to attribute the particularity of that abstraction to a cultural understanding of correspondence between the gray scale and the luminosity of the colors. All this in the joint invention of engraving and typography. / [es] Al identificar el objeto de la disciplina del diseño gráfico como el espacio gráfico de la lectura y su condición más específica en la experiencia de hacer visibles las palabras y las ideas, reconocemos desde el punto de vista del lector que todas las formas derivadas del uso del dibujo y la escritura, adquieren sentido en aquel espacio como consecuencia del poder universal de sus conexiones. A partir de esta perspectiva, identificamos que el objeto de esta investigación es el proceso de transferencia del conocimiento gráfico que ocurre durante la segunda mitad del siglo XV en el contexto de la implementación de la imprenta. Esto implica considerar cómo tipógrafos y grabadores realizan la transición desde la tradición del Manuscrito iluminado de la Edad Media hacia el advenimiento de la imprenta. Está tesis está enfocada en el campo de abstracción de los colores que conduce a comprender el carácter estructural que adquiere la escala de grises en el espacio gráfico, como consecuencia del consenso respecto de la prescindencia del uso de los colores en el libro impreso. Así, el objetivo de esta investigación es mostrar la relevancia de la luminosidad en espacio gráfico, considerando especialmente la comparación entre el carácter acromático del grabado y el aspecto inacabado del texto literario referidos al acto de leer. La observación de los aspectos geométricos, cromáticos y caligráficos en este contexto, nos permiten atribuir la particularidad de esa abstracción a una comprensión cultural de correspondencia entre la escala de grises y la luminosidad de los colores. Todo esto en la invención conjunta del grabado y la tipografía.