Transmission adaptative de modèles 3D massifs

Avec les progrès de l'édition de modèles 3D et des techniques de reconstruction 3D, de plus en plus de modèles 3D sont disponibles et leur qualité augmente. De plus, le support de la visualisation 3D sur le web s'est standardisé ces dernières années. Un défi majeur est donc de transmettre des modèles massifs à distance et de permettre aux utilisateurs de visualiser et de naviguer dans ces environnements virtuels. Cette thèse porte sur la transmission et l'interaction de contenus 3D et propose trois contributions majeures. Tout d'abord, nous développons une interface de navigation dans une scène 3D avec des signets -- de petits objets virtuels ajoutés à la scène sur lesquels l'utilisateur peut cliquer pour atteindre facilement un emplacement recommandé. Nous décrivons une étude d'utilisateurs où les participants naviguent dans des scènes 3D avec ou sans signets. Nous montrons que les utilisateurs naviguent (et accomplissent une tâche donnée) plus rapidement en utilisant des signets. Cependant, cette navigation plus rapide a un inconvénient sur les performances de la transmission : un utilisateur qui se déplace plus rapidement dans une scène a besoin de capacités de transmission plus élevées afin de bénéficier de la même qualité de service. Cet inconvénient peut être atténué par le fait que les positions des signets sont connues à l'avance : en ordonnant les faces du modèle 3D en fonction de leur visibilité depuis un signet, on optimise la transmission et donc, on diminue la latence lorsque les utilisateurs cliquent sur les signets. Deuxièmement, nous proposons une adaptation du standard de transmission DASH (Dynamic Adaptive Streaming over HTTP), très utilisé en vidéo, à la transmission de maillages texturés 3D. Pour ce faire, nous divisons la scène en un arbre k-d où chaque cellule correspond à un adaptation set DASH. Chaque cellule est en outre divisée en segments DASH d'un nombre fixe de faces, regroupant des faces de surfaces comparables. Chaque texture est indexée dans son propre adaptation set à différentes résolutions. Toutes les métadonnées (les cellules de l'arbre k-d, les résolutions des textures, etc.) sont référencées dans un fichier XML utilisé par DASH pour indexer le contenu: le MPD (Media Presentation Description). Ainsi, notre framework hérite de la scalabilité offerte par DASH. Nous proposons ensuite des algorithmes capables d'évaluer l'utilité de chaque segment de données en fonction du point de vue du client, et des politiques de transmission qui décident des segments à télécharger. Enfin, nous étudions la mise en place de la transmission et de la navigation 3D sur les appareils mobiles. Nous intégrons des signets dans notre version 3D de DASH et proposons une version améliorée de notre client DASH qui bénéficie des signets. Une étude sur les utilisateurs montre qu'avec notre politique de chargement adaptée aux signets, les signets sont plus susceptibles d'être cliqués, ce qui améliore à la fois la qualité de service et la qualité d'expérience des utilisateur

Sea Level Fluctuations

This thematic issue presents 11 scientific articles that are extremely useful for understanding the processes and phenomena of the interacting geospheres of the Earth. These processes have an important impact on the biosphere and many human activities. The results of scientific research presented in this book are fully united by the common theme "investigation of the fundamental foundations of the emergence, development, transformation, and interaction of hydroacoustic, hydrophysical and geophysical fields in the World Ocean." The book is recommended to a wide range of readers, as well as to specialists in the field of hydroacoustics, oceanology, and geophysics

Avaliação da qualidade de experiência de vídeo em várias tecnologias

Mestrado em Engenharia Eletrónica e TelecomunicaçõesNowadays the internet is associated with many services. Combined with this fact, there is a marked increase of the users joining this service. In this perspective, it is required that the service providers guarantee a minimum quality to the network services. The Quality of Experience of services is quite crucial in the development of services in networks. Also noteworthy, the tra c increase in multimedia services, including video streaming, increases the probability of congesting the networks. In the perspective of the service provider, the monitoring is a solution to avoid saturation in network. This way, this dissertation proposes to develop a platform that allows a multimedia tra c monitoring in the Meo Go service provided by the operator Portugal Telecom Communications. The architecture of the adaptive streaming over HTTP has been studied and tested to obtain the quality of experience metrics. This adaptive streaming technique presents the smooth streaming, an architecture made by Microsoft company, and it is used in the Meo Go service. Then, it is monitored the metrics obtained with the video player. This analysis is done objectively and subjectively. In this phase, the objective implementation of the method allows to obtain the prediction value of the Quality of Experience by consumers. The selected metrics were derived from the state / performance of network and terminal device. The obtained metrics aim to simulate human action in video score quality. Otherwise, subjectively, it is conducted a survey based in a questionnaire to compare methods. In this phase it was created an on-line platform to allow the obtain a greater number of rankings and data processing. In the obtained results, rstly in the smooth streaming player, it is shown the adaptive streaming implementation technique. On the next phase, test scenarios were created to demonstrate the functioning of the method in many cases, with greater relevance for those ones with higher dynamic complexity. From the perspective of subjective and objective methods, these have values that con rm the architecture of the implemented module. Over time, the performance of the scoring the quality of video streaming services approaches the one in a human mental action.Nos dias de hoje a Internet é um dos meios com mais serviços associados. Conjugado a este facto, existe um acentuado aumento de utilizadores a aderir a este serviço. Nesta perspectiva existe a necessidade de garantir uma qualidade mínima por parte dos prestadores de serviços. A Qualidade de Experiência que os consumidores têm dos serviços é bastante crucial no desenvolvimento e optimização dos serviços nas redes. É ainda de salientar que o aumento do tráfego multimédia, nomeadamente os streamings de vídeo, apresenta incrementos na probabilidade de as redes se congestionarem. Na perspectiva do prestador de serviços a monitorização é a solução para evitar a saturação total. Neste sentido, esta dissertação pretende desenvolver uma plataforma que permite a monitorização do tráfego de multimédia do serviço do Meo Go, fornecido pela operadora Portugal Telecom Comunicações. Neste trabalho foi necessário investigar e testar a arquitectura do streaming adaptativo sobre HTTP para ser possível obter métricas de qualidade de experiência. Este streaming adaptativo apresenta a técnica de smooth streaming, sendo esta arquitectura projectada pela empresa Microsoft e utilizada no serviço Meo Go. Posteriormente foram monitorizadas as métricas que se obtiveram no player de vídeo. Esta análise foi realizada de forma objectiva e subjectiva. Nesta fase da implementação objectiva do método em que se pretende obter uma predição do valor de Qualidade de Experiência por parte do consumidor, foram seleccionadas as métricas oriundas do estado/desempenho da rede e do dispositivo terminal. As métricas obtidas entram num processo de tratamento que pretende simular a ação humana nas classificações da qualidade dos vídeos. De outra forma, subjectivamente, foi realizada uma pesquisa, com base num questionário, de modo a comparar os métodos. Nesta etapa foi gerada uma plataforma online que possibilitou obter um maior número de classificações dos vídeos para posteriormente se proceder ao tratamento de dados. Nos resultados obtidos, primeiramente ao nível do player de smooth streaming, estes permitem analisar a técnica de implementação de streaming adaptativo. Numa fase seguinte foram criados cenários de teste para comprovar o funcionamento do método em diversas situações, tendo com maior relevância aqueles que contêm dinâmicas mais complexas. Na perspectiva dos métodos subjectivo e objectivo, estes apresentam valores que confirmam a arquitectura do módulo implementado. Adicionalmente, o desempenho do método em classificar a qualidade de serviço de vídeo streaming, ao longo do tempo, apresentou valores que se aproximam da dinâmica esperada numa ação mental humana

Realtime image noise reduction FPGA implementation with edge detection

The purpose of this dissertation was to develop and implement, in a Field Programmable Gate Array (FPGA), a noise reduction algorithm for real-time sensor acquired images. A Moving Average filter was chosen due to its fulfillment of a low demanding computational expenditure nature, speed, good precision and low to medium hardware resources utilization. The technique is simple to implement, however, if all pixels are indiscriminately filtered, the result will be a blurry image which is undesirable. Since human eye is more sensitive to contrasts, a technique was introduced to preserve sharp contour transitions which, in the author’s opinion, is the dissertation contribution. Synthetic and real images were tested. Synthetic, composed both with sharp and soft tone transitions, were generated with a developed algorithm, while real images were captured with an 8-kbit (8192 shades) high resolution sensor scaled up to 10 × 103 shades. A least-squares polynomial data smoothing filter, Savitzky-Golay, was used as comparison. It can be adjusted using 3 degrees of freedom ─ the window frame length which varies the filtering relation size between pixels’ neighborhood, the derivative order, which varies the curviness and the polynomial coefficients which change the adaptability of the curve. Moving Average filter only permits one degree of freedom, the window frame length. Tests revealed promising results with 2 and 4ℎ polynomial orders. Higher qualitative results were achieved with Savitzky-Golay’s better signal characteristics preservation, especially at high frequencies. FPGA algorithms were implemented in 64-bit integer registers serving two purposes: increase precision, hence, reducing the error comparatively as if it were done in floating-point registers; accommodate the registers’ growing cumulative multiplications. Results were then compared with MATLAB’s double precision 64-bit floating-point computations to verify the error difference between both. Used comparison parameters were Mean Squared Error, Signalto-Noise Ratio and Similarity coefficient.O objetivo desta dissertação foi desenvolver e implementar, em FPGA, um algoritmo de redução de ruído para imagens adquiridas em tempo real. Optou-se por um filtro de Média Deslizante por não exigir uma elevada complexidade computacional, ser rápido, ter boa precisão e requerer moderada utilização de recursos. A técnica é simples, mas se abordada como filtragem monotónica, o resultado é uma indesejável imagem desfocada. Dado o olho humano ser mais sensível ao contraste, introduziu-se uma técnica para preservar os contornos que, na opinião do autor, é a sua principal contribuição. Utilizaram-se imagens sintéticas e reais nos testes. As sintéticas, compostas por fortes e suaves contrastes foram geradas por um algoritmo desenvolvido. As reais foram capturadas com um sensor de alta resolução de 8-kbit (8192 tons) e escalonadas a 10 × 103 tons. Um filtro com suavização polinomial de mínimos quadrados, SavitzkyGolay, foi usado como comparação. Possui 3 graus de liberdade: o tamanho da janela, que varia o tamanho da relação de filtragem entre os pixels vizinhos; a ordem da derivada, que varia a curvatura do filtro e os coeficientes polinomiais, que variam a adaptabilidade da curva aos pontos a suavizar. O filtro de Média Deslizante é apenas ajustável no tamanho da janela. Os testes revelaram-se promissores nas 2ª e 4ª ordens polinomiais. Obtiveram-se resultados qualitativos com o filtro Savitzky-Golay que detém melhores características na preservação do sinal, especialmente em altas frequências. Os algoritmos em FPGA foram implementados em registos de vírgula fixa de 64-bits, servindo dois propósitos: aumentar a precisão, reduzindo o erro comparativamente ao terem sido em vírgula flutuante; acomodar o efeito cumulativo das multiplicações. Os resultados foram comparados com os cálculos de 64-bits obtidos pelo MATLAB para verificar a diferença de erro entre ambos. Os parâmetros de medida foram MSE, SNR e coeficiente de Semelhança

Modélisation et distribution adaptatives de grandes scènes naturelles

Cette thèse traite de la modélisation et la diffusion de grandes scènes 3D naturelles. Nous visons à fournir des techniques pour permettre à des utilisateurs de naviguer à distance dans une scène 3D naturelle, tout en assurant la cohérence botanique et l'interactivité. Tout d'abord, nous fournissons une technique de compression multi-résolution, fondée sur la normalisation, l'instanciation, la décorrélation, et sur le codage entropique des informations géometriques pour des modèles de plantes. Ensuite, nous étudions la transmission efficace de ces objets 3D. L'algorithme de paquétisation proposé fonctionne pour la plupart des représentations multi-résolution d'objet 3D. Nous validons les techniques de paquétisation par des expériences sur un WAN (Wide Area Network), avec et sans contrôle de congestion (Datagram Congestion Control Protocol). Enfin, nous abordons les questions du streaming au niveau de la scène. Nous optimisons le traitement des requêtes du côté serveur en fournissant une structure de données adaptée et nous préparons le terrain pour nos travaux futurs sur l'évolutivité et le déploiement de systèmes distribués de streaming 3D. ABSTRACT : This thesis deals with the modeling and the interactive streaming of large natural 3D scenes. We aim at providing techniques to allow the remote walkthrough of users in a natural 3D scene ensuring botanical coherency and interactivity.First, we provide a compact and progressive representation for botanically realistic plant models. The topological structure and the geometry of the plants are represented by generalized cylinders. We provide a multi-resolution compression scheme, based on standardization and instantiation, on difference-based decorrelation, and on entropy coding. Then, we study efficient transmission of these 3D objects. The proposed packetization scheme works for any multi-resolution 3D representation. We validate our packetization schemes with extensive experiments over a WAN (Wide Area Network), with and without congestion control (Datagram Congestion Control Protocol). Finally, we address issues on streaming at the scene-level. We optimize the viewpoint culling requests on server-side by providing an adapted datastructure and we prepare the ground for our further work on scalability and deployment of distributed 3D streaming systems

Adaptive Modeling and Distribution of Large Natural Scenes

This thesis deals with the modeling and the interactive streaming of large natural 3D scenes. We aim at providing techniques to allow the remote walkthrough of users in a natural 3D scene ensuring botanical coherency and interactivity.First, we provide a compact and progressive representation for botanically realistic plant models. The topological structure and the geometry of the plants are represented by generalized cylinders. We provide a multi-resolution compression scheme, based on standardization and instantiation, on difference-based decorrelation, and on entropy coding. Then, we study efficient transmission of these 3D objects. The proposed packetization scheme works for any multi-resolution 3D representation. We validate our packetization schemes with extensive experiments over a WAN (Wide Area Network), with and without congestion control (Datagram Congestion Control Protocol). Finally, we address issues on streaming at the scene-level. We optimize the viewpoint culling requests on server-side by providing an adapted datastructure and we prepare the ground for our further work on scalability and deployment of distributed 3D streaming systems

Mobile journalism at RTP: production of news - using the smartphone as a tool for news production

The goal of this paper is to show case a practical resolution for the integration a ta greater scale of the Mobile Journalism philosophy, both in the production and in the consumption of news. The production-side concerns the use of the smartphone and other light equipment in the production of news, while the consumption-side concerns how the news are displayed and consumed on a smartphone. This work project was realized in syndication with RTP and was adjust and tailored to its respective needs, resources and objectives. In order to achieve this goal, several analysis were developed to address the external and internal environment, identifying the opportunities and threats of the broad casting industry and the strenggic recommendations that ensures a work able dissemination plan for Mobile Journalism

Content-Aware Multimedia Communications

The demands for fast, economic and reliable dissemination of multimedia information are steadily growing within our society. While people and economy increasingly rely on communication technologies, engineers still struggle with their growing complexity. Complexity in multimedia communication originates from several sources. The most prominent is the unreliability of packet networks like the Internet. Recent advances in scheduling and error control mechanisms for streaming protocols have shown that the quality and robustness of multimedia delivery can be improved significantly when protocols are aware of the content they deliver. However, the proposed mechanisms require close cooperation between transport systems and application layers which increases the overall system complexity. Current approaches also require expensive metrics and focus on special encoding formats only. A general and efficient model is missing so far. This thesis presents efficient and format-independent solutions to support cross-layer coordination in system architectures. In particular, the first contribution of this work is a generic dependency model that enables transport layers to access content-specific properties of media streams, such as dependencies between data units and their importance. The second contribution is the design of a programming model for streaming communication and its implementation as a middleware architecture. The programming model hides the complexity of protocol stacks behind simple programming abstractions, but exposes cross-layer control and monitoring options to application programmers. For example, our interfaces allow programmers to choose appropriate failure semantics at design time while they can refine error protection and visibility of low-level errors at run-time. Based on some examples we show how our middleware simplifies the integration of stream-based communication into large-scale application architectures. An important result of this work is that despite cross-layer cooperation, neither application nor transport protocol designers experience an increase in complexity. Application programmers can even reuse existing streaming protocols which effectively increases system robustness.Der Bedarf unsere Gesellschaft nach kostengünstiger und zuverlässiger Kommunikation wächst stetig. Während wir uns selbst immer mehr von modernen Kommunikationstechnologien abhängig machen, müssen die Ingenieure dieser Technologien sowohl den Bedarf nach schneller Einführung neuer Produkte befriedigen als auch die wachsende Komplexität der Systeme beherrschen. Gerade die Übertragung multimedialer Inhalte wie Video und Audiodaten ist nicht trivial. Einer der prominentesten Gründe dafür ist die Unzuverlässigkeit heutiger Netzwerke, wie z.B.~dem Internet. Paketverluste und schwankende Laufzeiten können die Darstellungsqualität massiv beeinträchtigen. Wie jüngste Entwicklungen im Bereich der Streaming-Protokolle zeigen, sind jedoch Qualität und Robustheit der Übertragung effizient kontrollierbar, wenn Streamingprotokolle Informationen über den Inhalt der transportierten Daten ausnutzen. Existierende Ansätze, die den Inhalt von Multimediadatenströmen beschreiben, sind allerdings meist auf einzelne Kompressionsverfahren spezialisiert und verwenden berechnungsintensive Metriken. Das reduziert ihren praktischen Nutzen deutlich. Außerdem erfordert der Informationsaustausch eine enge Kooperation zwischen Applikationen und Transportschichten. Da allerdings die Schnittstellen aktueller Systemarchitekturen nicht darauf vorbereitet sind, müssen entweder die Schnittstellen erweitert oder alternative Architekturkonzepte geschaffen werden. Die Gefahr beider Varianten ist jedoch, dass sich die Komplexität eines Systems dadurch weiter erhöhen kann. Das zentrale Ziel dieser Dissertation ist es deshalb, schichtenübergreifende Koordination bei gleichzeitiger Reduzierung der Komplexität zu erreichen. Hier leistet die Arbeit zwei Beträge zum aktuellen Stand der Forschung. Erstens definiert sie ein universelles Modell zur Beschreibung von Inhaltsattributen, wie Wichtigkeiten und Abhängigkeitsbeziehungen innerhalb eines Datenstroms. Transportschichten können dieses Wissen zur effizienten Fehlerkontrolle verwenden. Zweitens beschreibt die Arbeit das Noja Programmiermodell für multimediale Middleware. Noja definiert Abstraktionen zur Übertragung und Kontrolle multimedialer Ströme, die die Koordination von Streamingprotokollen mit Applikationen ermöglichen. Zum Beispiel können Programmierer geeignete Fehlersemantiken und Kommunikationstopologien auswählen und den konkreten Fehlerschutz dann zur Laufzeit verfeinern und kontrolliere

Esports and the Media

This book takes a multidisciplinary approach to the question of esports and their role in society. A diverse group of authors tackle the impact of esports and the ways in which it has grown within the entertainment industry around the world. Chapters offer a coherent response to the following questions: What role do esports play in the entertainment industry? What communication skills can be learned through esports? What do the media gain from broadcasting esports? What is the relationship between social networks and esports? What are the main marketing strategies used in esports? What effect does communicative globalization have on the development of esports? What is the relationship between merchandising and esports? What do communication experts think about esports? Offering clear insights into this rapidly developing area, this volume will be of great interest to scholars, students, and anyone working in game studies, new media, leisure, sport studies, communication studies, transmedia literacy, and digital culture