[EN] PIXEL PATTERNS: Aesthetic and technical barriers in video games (1972 - 2000) Video games are inherently technological and, therefore, are subject to an evolution of the technology. However, the creative process is not governed by technical limitations of any kind. That is why, throughout history have emerged a series of designers who have managed to develop a wide range of technical approaches in order to ensure aesthetic over technology. This doctoral thesis objective is to study and analyze the different processes developed in video games in order to overcome any technical impediment. It was necessary to study each of these processes in relation to their historical context, so we analyzed the chronological development of the video game industry. We've structured the thesis following a theoretical methodology of analysis and synthesis, applying a historical documentation, and proposing a chronological study of the evolution through the three great systems of visual representation in the history of video games: illustration, sprites and polygons. Each of these parts is organized in chapters structured to turn into three parts: historiographical analysis, analysis of the developed technique and analysis of the subsequent impact of the process. One of the main contributions of this research has been the finding that the creative process is capable of overcoming even the technical impossibilities. As a result, this study has produced full documentation, not only of the architects and creators of these processes, but also of the main visual tricks that emerged in the history of video games. / [ES] PIXEL PATTERNS: Estética y barreras técnicas en los videojuegos (1972 - 2000) Los videojuegos son un medio inherentemente tecnológico y, por lo tanto, se encuentran sujetos a una evolución de la técnica. Sin embargo, el proceso creativo no se rige por limitaciones técnicas de ningún tipo. Por ello, a lo largo de la historia han surgido una serie de diseñadores que han conseguido desarrollar toda una gama de planteamientos destinados a que la técnica reine sobre la estética. Esta Tesis Doctoral tiene como objetivo general estudiar y analizar los diferentes procesos que se han desarrollado en los videojuegos con el fin de superar cualquier tipo de impedimento técnico. Para lograr este objetivo ha sido necesario estudiar cada uno de estos procesos en relación con su contexto histórico, por lo que hemos realizado una revisión del desarrollo cronológico de la industria del videojuego. Hemos estructurado la tesis siguiendo una metodología teórica de análisis y síntesis, aplicando una documentación histórica y planteando un estudio cronológico de la evolución a través de los tres grandes sistemas de representación visual en la historia de los videojuegos: Ilustración, Sprites y Polígonos. Cada una de estas partes se organiza en capítulos estructurados a su vez en tres partes: análisis historiográfico, análisis de la técnica desarrollada y análisis de las repercusiones posteriores de la misma. Una de las aportaciones principales de esta investigación ha sido la constatación de que el proceso creativo es capaz de superar las imposibilidades técnicas. Como resultado de este estudio se ha elaborado una completa documentación, no solo de los artífices y creadores de estos procesos, sino también de los principales artificios visuales surgidos en el medio de los videojuegos. / [CA] PÍXEL PATTERNS: Estètica i barreres tècniques en els videojocs (1972 - 2000) Els videojocs són un mitjà inherentment tecnològic i, per tant, es troben subjectes a una evolució de la tècnica. No obstant això, el procés creatiu no es regix per limitacions tècniques de cap tipus. Per això, al llarg de la història han sorgit una sèrie de dissenyadors que han aconseguit crear tota una gamma de plantejaments destinats a què la tècnica regne sobre l'estètica. Esta Tesi Doctoral té com a objectiu general estudiar i analitzar els diferents processos que s'han desenrotllat en els videojocs a fi de superar qualsevol tipus d'impediment tècnic. Per a aconseguir este objectiu ha sigut necessari estudiar cada un d'estos processos en relació amb el seu context històric, per la qual cosa hem realitzat una revisió del desenvolupament cronològic de la indústria del videojoc. Hem estructurat la tesi seguint una metodologia teòrica d'anàlisi i síntesi, aplicant una documentació històrica i plantejant un estudi cronològic de l'evolució a través dels tres grans sistemes de representació visual en la història dels videojocs: Il·lustració, Sprites i Polígons. Cada una d'estes parts s'organitza en capítols estructurats al seu torn en tres parts: anàlisi historiogràfica, anàlisi de la tècnica i anàlisi de les repercussions posteriors de la mateixa. Una de les aportacions principals d'esta investigació ha sigut la constatació que el procés creatiu és capaç de superar inclús les impossibilitats tècniques. Com resultat d'este estudi s'ha elaborat una completa documentació, no sols dels artífexs i creadors d'estos processos, sinó també dels principals artificis visuals sorgits en el mig dels videojocs. / Cabrera Carbonell, J. (2015). PIXEL PATTERNS: ESTÉTICA Y BARRERAS TÉCNICAS EN LOS VIDEOJUEGOS (1972 - 2000) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59224

O Sistema ALIS (Atmospheric Limb Imaging System), do Instituto Nacional de Pesquisas Espaciais (INPE) em São José dos Campos, a bordo do satélite EQUARS (Equatorial Atmosphere Research Satellite), tem como objetivo observar três fenômenos ópticos da atmosfera na direção horizontal (Limb) do satélite em órbita: a aeroluminescência, os relâmpagos e os sprites. Os sprites são fenômenos luminosos verticais que ocorrem na mesosfera e ionosfera inferior de coloração vermelho-alaranjada e o seu estudo é de grande importância devido à influência que exerce sobre o clima terrestre, juntamente com demais fenômenos. O objetivo deste projeto é a criação de um software capaz de identificar relâmpagos e sprites capturados por meio de um CCD e, através desta identificação, decidir quais imagens devem ser guardadas para posterior envio e quais devem ser descartadas. Estudos preliminares demonstram que por meio de técnicas de segmentação de imagem utilizando-se contorno ativo (que poderiam ser empregados em uma posterior análise de formas) e compactação por meio de wavelets é possível reconhecer, localizar e guardar aqueles fenômenos que forem de interesse. / THe Atmospheric Limb Imaging System (ALIS), from Brazilian National Institute for Space Research (INPE), embedded in the Equatorial Atmosphere Research Satellite (EQUARS) aims at searching for three optical phenomena along the Earth’s Limb: airglow, lightning and sprites. Sprites are vertical luminous phenomena that occur in the mesosphere and inferior ionosphere of red-orange coloration. The gathering of knowledge on sprites is of great importance do to their influence over the terrestrial climate, together with the other phenomena. The objective of this project is to create a software tool capable of identifying lightnings and sprites captured by a CCD camera. From this identification the tool can decide which images should be kept for subsequent upload and which should be discarded. Preliminary studies have demonstrated that through image segmentation techniques with active contour (that could be employed in a subsequent shape analysis process) and wavelet-based compression methods it is possible to recognize, locate and preserv those phenomena of interest.

O Sistema ALIS (Atmospheric Limb Imaging System), do Instituto Nacional de Pesquisas Espaciais (INPE) em São José dos Campos, a bordo do satélite EQUARS (Equatorial Atmosphere Research Satellite), tem como objetivo observar três fenômenos ópticos da atmosfera na direção horizontal (Limb) do satélite em órbita: a aeroluminescência, os relâmpagos e os sprites. Os sprites são fenômenos luminosos verticais que ocorrem na mesosfera e ionosfera inferior de coloração vermelho-alaranjada e o seu estudo é de grande importância devido à influência que exerce sobre o clima terrestre, juntamente com demais fenômenos. O objetivo deste projeto é a criação de um software capaz de identificar relâmpagos e sprites capturados por meio de um CCD e, através desta identificação, decidir quais imagens devem ser guardadas para posterior envio e quais devem ser descartadas. Estudos preliminares demonstram que por meio de técnicas de segmentação de imagem utilizando-se contorno ativo (que poderiam ser empregados em uma posterior análise de formas) e compactação por meio de wavelets é possível reconhecer, localizar e guardar aqueles fenômenos que forem de interesse. / THe Atmospheric Limb Imaging System (ALIS), from Brazilian National Institute for Space Research (INPE), embedded in the Equatorial Atmosphere Research Satellite (EQUARS) aims at searching for three optical phenomena along the Earth’s Limb: airglow, lightning and sprites. Sprites are vertical luminous phenomena that occur in the mesosphere and inferior ionosphere of red-orange coloration. The gathering of knowledge on sprites is of great importance do to their influence over the terrestrial climate, together with the other phenomena. The objective of this project is to create a software tool capable of identifying lightnings and sprites captured by a CCD camera. From this identification the tool can decide which images should be kept for subsequent upload and which should be discarded. Preliminary studies have demonstrated that through image segmentation techniques with active contour (that could be employed in a subsequent shape analysis process) and wavelet-based compression methods it is possible to recognize, locate and preserv those phenomena of interest.

The purpose with this thesis is to investigate whether Sprite Kit is a good tool to simplify the development process for game developers when making 2D games for mobile devices. To answer this question a simple turn based strategy game has been developed with Sprite Kit. Sprite Kit is a game engine for making 2D games released by Apple. Based on the experience I got during the development I will go through and discuss some of the most important tools provided by the game engine and how they helped us to complete our game. The conclusions I reached after making a game with Sprite Kit is that the frame- work provides all the tools necessary for creating a simple 2D mobile game for iOS. Sprite Kit hides much of the lower level details and gives the game de- veloper comprehensive development support. This helps the game developer to save a lot of time and focus more on the gameplay when creating a game.

La SER (Surface Équivalente Radar) est une grandeur caractérisant le pouvoir rétrodiffuseurd’une cible soumise à un champ électromagnétique. Dans de nombreuses applications,il est capital d’analyser et de contrôler la SER. L’imagerie 3D est l’outil adapté pourlocaliser et caractériser en trois dimensions les principaux contributeurs à la SER. Cependant,ce traitement est un problème de synthèse de Fourier qui n’est pas inversible car il y aplus d’inconnues que de données. Les méthodes conventionnelles telles que le Polar FormatAlgorithm, consistant en un reformatage des données avec complétion de zéro suivi d’unetransformée de Fourier inverse rapide, fournissent des résultats de qualité limitée.Dans ce travail, nous proposons une nouvelle méthode haute résolution. Elle est dénomméeSPRITE (pour SParse Radar Imaging TEchnique) et permet d’accroître considérablementla qualité des cartes de rétro-diffusion estimées. Elle repose sur une régularisation duproblème consistant en la prise en compte d’informations a priori de parcimonie et d’uneinformation de support. La solution est alors définie comme le minimiseur d’un critère pénaliséet contraint. L’optimisation est assurée par l’algorithme primal-dual ADMM (AlternatingDirection Method of Multiplier) dont une adaptation aux spécificités du problème mène à descalculs efficaces à l’aide de transformées de Fourier rapides.Finalement, la méthode est évaluée sur des données synthétiques et réelles. Comparativementà la méthode conventionnelle, la résolution est drastiquement accrue. Les images 3Dproduites sont alors un outil particulièrement adapté à l’analyse et au contrôle de SER. / The RCS (Radar Cross Section) is a quantity which characterizes the scattering power ofa target exposed to an electromagnetic field. Its analysis and control are important in manyapplications. 3D imaging is a suitable tool to accurately locate and characterize in 3D themain contributors to the RCS. However, this is a non-invertible Fourier synthesis problembecause the number of unknowns is larger than the number of data. Conventional methodssuch as the Polar Format Algorithm, which consists of data reformatting including zeropaddingfollowed by a fast inverse Fourier transform, provide results of limited quality.In this work, we propose a new high resolution method, named SPRITE (for SParse RadarImaging TEchnique), which considerably increases the quality of the estimated RCS maps. Itis based on a regularization scheme that accounts for information of sparsity and support. Thesolution is then defined as the minimizer of a penalized and constrained criterion. Optimizationis ensured by an appropriate adaptation of the ADMM (Alternating Direction Methodof Multiplier) algorithm that is able to quickly perform calculations using fast Fourier transforms.Finally, the method is evaluated on both simulated and real data. Compared to the conventionalmethod, the resolution is significantly increased and the images can support a betterRCS analysis and control.

Video compression aims to reduce video file size without impacting visual quality. Existing algorithms mostly use transform coders to convert information from the spatial to frequency domain, and attenuate or remove high frequency components from the sequence. This enables the omission of a large proportion of high frequency information with no discernible visual impact. Sprite-based compression encodes large portions of a scene as a single object in the video sequence, recreating the object in subsequent frames by warping or morphing the sprite to mimic changes in subsequent frames. This thesis sought to improve several aspects of existing sprite based compression approaches, employing a temporal motion model using a low order polynomial to represent the motion of an object across multiple frames in a single model rather than a series of models. The main outcome is the demonstration that motion models used by sprite based video compression can be extended to a full three dimensional model, reducing the overall size of the model, and improving the quality of the sequence at low bit rates. A second outcome is the demonstration that super-resolution processing is not necessary if lanczos spatial interpolation is used instead of bilinear or bi-cubic interpolation, resulting in a savings in computational time and resources. A third outcome is the introduction of a new blending model used to generate image mosaics that improves the quality of the synthesised sequence when zoom is present in the sequence for a given bit-rate. A final outcome is demonstrating that performing superresolution processing and sub-sampling back to the original resolution prior to compression provides benefits in some circumstances.

Image generation has been taking large strides and new models showing great potential have been created. One of the continued struggles with image generation is controlling what the output will be, with no real way of guiding the generation into creating what the user wants. This has now been improved with the creation of text-image similarity models, which can be used together with an image generation model to guide the generation. This thesis will examine this new method of using a text-image similarity model and see how well it can generate pixel art of humanoid characters. The thesis compares the popular model Diffusion with a simple image generation method that relies solely on the text-image similarity models guidance. The results show that combining a diffusion model with a text-image similarity model improves the results over only using the text-image similarity model in almost every regard. Using a text-image similarity model allows the user to guide the generation, although sometimes the model will misinterpret the request. / Bildgeneration har tagit stora steg och nya modeller har tagits fram som visar stor potential. En av de forsatta svårigheterna med bildgeneration är att kontrollera vad modellen genererar. De nya text-bild-likhet modellerna förenklar nu för användare att tillsammans med en bildgenerator modell använda text-bild-likhet modellen att styra bildgeneratorn. Den här uppsatsen kommer utforska den nya metoden och se hur väl den kan användas för att generera mänskliga pixel art karaktärer. I uppsatsen kommer den populära Diffusion modellen jämföras med en enkel ritmetod som styrs av text-bild likhet modeller. Resultatet visar att kombinationen av en Diffusion modell och text-bild likhets modell ökar prestandan på nästan alla sätt i jämförelse med att låta text-bild-likhets modellen styra bildgeneratorn helt och hållet. Det visar sig att text-bild likhet modellen kan användas för att styra generationen men ibland så missförstår modellen vad som önskas.

This thesis presents new approaches to image registration and super-resolution mosaicing as well as their applications. Firstly, a feature-based image registration method is proposed for a multisensor surveillance system that consists of an optical camera and an infrared camera. By integrating a non-rigid object tracking technique into this method, a novel approach to simultaneous object tracking and multisensor image registration is proposed. Based on the registration and fusion of multisensor information, automatic face detection is greatly improved. Secondly, some extensions of a gradient-based image registration method, called inverse compositional algorithm, are proposed. These extensions include cumulative multi-image registration and the incorporation of illumination change and lens distortion correction. They are incorporated into the framework of the original algorithm in a consistent manner and efficiency can still be achieved for multi-image registration with illumination and lens distortion correction. Thirdly, new super-resolution mosaicing algorithms are proposed for multiple uncompressed and compressed images. Considering the process of image formation, observation models are introduced to describe the relationship between the superresolution mosaic image and the uncompressed and compressed low-resolution images. To improve the performance of super-resolution mosaicing, a wavelet-based image interpolation technique and an approach to adaptive determination of the regularization parameter are presented. For compressed images, a spatial-domain algorithm and a transform-domain algorithm are proposed. All the proposed superresolution mosaicing algorithms are robust against outliers. They can produce superresolution mosaics and reconstructed super-resolution images with improved subjective quality. Finally, new techniques for super-resolution sprite generation and super-resolution sprite coding are proposed. Considering both short-term and long-term motion influences, an object-based image registration method is proposed for handling long image sequences. In order to remove the influence of outliers, a robust technique for super-resolution sprite generation is presented. This technique produces sprite images and reconstructed super-resolution images with high visual quality. Moreover, it provides better reconstructed low-resolution images compared with low-resolution sprite generation techniques. Due to the advantages of the super-resolution sprite, a super-resolution sprite coding technique is also proposed. It achieves high coding efficiency especially at a low bit-rate and produces both decoded low-resolution and super-resolution images with improved subjective quality. Throughout this work, the performance of all the proposed algorithms is evaluated using both synthetic and real image sequences.

The simulation of natural phenomena such as clouds, smoke, fire and water is one of the most important research areas in computer graphics. Clouds are an essential component of any outdoor virtual environment, they add an important element of visual detail without which the environment would feel unrealistic. This paper describes an approach for setting up a cloud simulation. Clouds in our system are modeled using cellular automaton. To accelerate the simulation and its visualization, we implement both  entirely on programmable floating-point graphics hardware. The main part of the algorithm is implemented in a fragment shader and therefore takes full advantage of the highly parallel structure. The algorithm can generate result at real-time or near real-time frame rates. We also simulate the interaction of clouds with light, including self-shadowing.

The lightning is the natural source of electromagnetic radiation. It is an atmospheric electrical discharge.  However, since recent times, it was discovered that there are other types of lightning besides those that are visible to the naked eye. They are called TLEs (Transient Luminous Event) and take place above the clouds during thunderstorms. Distinct classification is applied to the various existing TLEs in compliance with their shapes, size, color, altitude, origin and duration. Thus, all Transient Luminous Events are categorized to the following types: elves, spites, halos, blue jets, blue starters, gigantic jets, trolls, gnomes, pixies and ghosts. TLE investigation missions are important for several scientific purposes. They allow to gain an understanding of the lightning creation processes, contribution on global electric circuits as well as chemical influence on the Earth’s climate.  TLE observations can be performed by lightning detection and location systems which differs according to their location. They can be ground-based, space-based as well as carried on aircraft or balloon. Lightning location systems in space are usually conducted on large-, medium- or micro-sized satellites.  The main scope of this thesis is to explore and describe all possible and known methods and techniques of TLE investigation as well as discussions of gained observation results for better understanding and further analysis of more suitable instruments for TLE detection mission on LEO orbit. Analysis of suitable equipment will be done according to the conclusion made from considered lightning detection systems with similar missions and pursuant to nanosatellite requirements.