1,580 research outputs found

    Design of a digital compression technique for shuttle television

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    The determination of the performance and hardware complexity of data compression algorithms applicable to color television signals, were studied to assess the feasibility of digital compression techniques for shuttle communications applications. For return link communications, it is shown that a nonadaptive two dimensional DPCM technique compresses the bandwidth of field-sequential color TV to about 13 MBPS and requires less than 60 watts of secondary power. For forward link communications, a facsimile coding technique is recommended which provides high resolution slow scan television on a 144 KBPS channel. The onboard decoder requires about 19 watts of secondary power

    AXMEDIS 2008

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    The AXMEDIS International Conference series aims to explore all subjects and topics related to cross-media and digital-media content production, processing, management, standards, representation, sharing, protection and rights management, to address the latest developments and future trends of the technologies and their applications, impacts and exploitation. The AXMEDIS events offer venues for exchanging concepts, requirements, prototypes, research ideas, and findings which could contribute to academic research and also benefit business and industrial communities. In the Internet as well as in the digital era, cross-media production and distribution represent key developments and innovations that are fostered by emergent technologies to ensure better value for money while optimising productivity and market coverage

    Software-Defined Radio Demonstrators: An Example and Future Trends

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    Software-defined radio requires the combination of software-based signal processing and the enabling hardware components. In this paper, we present an overview of the criteria for such platforms and the current state of development and future trends in this area. This paper will also provide details of a high-performance flexible radio platform called the maynooth adaptable radio system (MARS) that was developed to explore the use of software-defined radio concepts in the provision of infrastructure elements in a telecommunications application, such as mobile phone basestations or multimedia broadcasters

    Interactive mixed reality rendering in a distributed ray tracing framework

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    The recent availability of interactive ray tracing opened the way for new applications and for improving existing ones in terms of quality. Since today CPUs are still too slow for this purpose, the necessary computing power is obtained by connecting a number of machines and using distributed algorithms. Mixed reality rendering - the realm of convincingly combining real and virtual parts to a new composite scene - needs a powerful rendering method to obtain a photorealistic result. The ray tracing algorithm thus provides an excellent basis for photorealistic rendering and also advantages over other methods. It is worth to explore its abilities for interactive mixed reality rendering. This thesis shows the applicability of interactive ray tracing for mixed (MR) and augmented reality (AR) applications on the basis of the OpenRT framework. Two extensions to the OpenRT system are introduced and serve as basic building blocks: streaming video textures and in-shader AR view compositing. Streaming video textures allow for inclusion of the real world into interactive applications in terms of imagery. The AR view compositing mechanism is needed to fully exploit the advantages of modular shading in a ray tracer. A number of example applications from the entire spectrum of the Milgram Reality-Virtuality continuum illustrate the practical implications. An implementation of a classic AR scenario, inserting a virtual object into live video, shows how a differential rendering method can be used in combination with a custom build real-time lightprobe device to capture the incident light and include it into the rendering process to achieve convincing shading and shadows. Another field of mixed reality rendering is the insertion of real actors into a virtual scene in real-time. Two methods - video billboards and a live 3D visual hull reconstruction - are discussed. The implementation of live mixed reality systems is based on a number of technologies beside rendering and a comprehensive understanding of related methods and hardware is necessary. Large parts of this thesis hence deal with the discussion of technical implementations and design alternatives. A final summary discusses the benefits and drawbacks of interactive ray tracing for mixed reality rendering.Die VerfĂŒgbarkeit von interaktivem Ray-Tracing ebnet den Weg fĂŒr neue Anwendungen, aber auch fĂŒr die Verbesserung der QualitĂ€t bestehener Methoden. Da die heute verfĂŒgbaren CPUs noch zu langsam sind, ist es notwendig, mehrere Maschinen zu verbinden und verteilte Algorithmen zu verwenden. Mixed Reality Rendering - die Technik der ĂŒberzeugenden Kombination von realen und synthetischen Teilen zu einer neuen Szene - braucht eine leistungsfĂ€hige Rendering-Methode um photorealistische Ergebnisse zu erzielen. Der Ray-Tracing-Algorithmus bietet hierfĂŒr eine exzellente Basis, aber auch Vorteile gegenĂŒber anderen Methoden. Es ist naheliegend, die Möglichkeiten von Ray-Tracing fĂŒr Mixed-Reality-Anwendungen zu erforschen. Diese Arbeit zeigt die Anwendbarkeit von interaktivem Ray-Tracing fĂŒr Mixed-Reality (MR) und Augmented-Reality (AR) Anwendungen anhand des OpenRT-Systems. Zwei Erweiterungen dienen als Grundbausteine: Videotexturen und In-Shader AR View Compositing. Videotexturen erlauben die reale Welt in Form von Bildern in den Rendering-Prozess mit einzubeziehen. Der View-Compositing-Mechanismus is notwendig um die ModularitĂ€t einen Ray-Tracers voll auszunutzen. Eine Reihe von Beispielanwendungen von beiden Enden des Milgramschen Reality-Virtuality-Kontinuums verdeutlichen die praktischen Aspekte. Eine Implementierung des klassischen AR-Szenarios, das EinfĂŒgen eines virtuellen Objektes in eine Live-Übertragung zeigt, wie mittels einer Differential Rendering Methode und einem selbstgebauten GerĂ€t zur Erfassung des einfallenden Lichts realistische Beleuchtung und Schatten erzielt werden können. Ein anderer Anwendungsbereich ist das EinfĂŒgen einer realen Person in eine kĂŒnstliche Szene. Hierzu werden zwei Methoden besprochen: Video-Billboards und eine interaktive 3D Rekonstruktion. Da die Implementierung von Mixed-Reality-Anwendungen Kentnisse und VerstĂ€ndnis einer ganzen Reihe von Technologien nebem dem eigentlichen Rendering voraus setzt, ist eine Diskussion der technischen Grundlagen ein wesentlicher Bestandteil dieser Arbeit. Dies ist notwenig, um die Entscheidungen fĂŒr bestimmte Designalternativen zu verstehen. Den Abschluss bildet eine Diskussion der Vor- und Nachteile von interaktivem Ray-Tracing fĂŒr Mixed Reality Anwendungen

    Interactive mixed reality rendering in a distributed ray tracing framework

    Get PDF
    The recent availability of interactive ray tracing opened the way for new applications and for improving existing ones in terms of quality. Since today CPUs are still too slow for this purpose, the necessary computing power is obtained by connecting a number of machines and using distributed algorithms. Mixed reality rendering - the realm of convincingly combining real and virtual parts to a new composite scene - needs a powerful rendering method to obtain a photorealistic result. The ray tracing algorithm thus provides an excellent basis for photorealistic rendering and also advantages over other methods. It is worth to explore its abilities for interactive mixed reality rendering. This thesis shows the applicability of interactive ray tracing for mixed (MR) and augmented reality (AR) applications on the basis of the OpenRT framework. Two extensions to the OpenRT system are introduced and serve as basic building blocks: streaming video textures and in-shader AR view compositing. Streaming video textures allow for inclusion of the real world into interactive applications in terms of imagery. The AR view compositing mechanism is needed to fully exploit the advantages of modular shading in a ray tracer. A number of example applications from the entire spectrum of the Milgram Reality-Virtuality continuum illustrate the practical implications. An implementation of a classic AR scenario, inserting a virtual object into live video, shows how a differential rendering method can be used in combination with a custom build real-time lightprobe device to capture the incident light and include it into the rendering process to achieve convincing shading and shadows. Another field of mixed reality rendering is the insertion of real actors into a virtual scene in real-time. Two methods - video billboards and a live 3D visual hull reconstruction - are discussed. The implementation of live mixed reality systems is based on a number of technologies beside rendering and a comprehensive understanding of related methods and hardware is necessary. Large parts of this thesis hence deal with the discussion of technical implementations and design alternatives. A final summary discusses the benefits and drawbacks of interactive ray tracing for mixed reality rendering.Die VerfĂŒgbarkeit von interaktivem Ray-Tracing ebnet den Weg fĂŒr neue Anwendungen, aber auch fĂŒr die Verbesserung der QualitĂ€t bestehener Methoden. Da die heute verfĂŒgbaren CPUs noch zu langsam sind, ist es notwendig, mehrere Maschinen zu verbinden und verteilte Algorithmen zu verwenden. Mixed Reality Rendering - die Technik der ĂŒberzeugenden Kombination von realen und synthetischen Teilen zu einer neuen Szene - braucht eine leistungsfĂ€hige Rendering-Methode um photorealistische Ergebnisse zu erzielen. Der Ray-Tracing-Algorithmus bietet hierfĂŒr eine exzellente Basis, aber auch Vorteile gegenĂŒber anderen Methoden. Es ist naheliegend, die Möglichkeiten von Ray-Tracing fĂŒr Mixed-Reality-Anwendungen zu erforschen. Diese Arbeit zeigt die Anwendbarkeit von interaktivem Ray-Tracing fĂŒr Mixed-Reality (MR) und Augmented-Reality (AR) Anwendungen anhand des OpenRT-Systems. Zwei Erweiterungen dienen als Grundbausteine: Videotexturen und In-Shader AR View Compositing. Videotexturen erlauben die reale Welt in Form von Bildern in den Rendering-Prozess mit einzubeziehen. Der View-Compositing-Mechanismus is notwendig um die ModularitĂ€t einen Ray-Tracers voll auszunutzen. Eine Reihe von Beispielanwendungen von beiden Enden des Milgramschen Reality-Virtuality-Kontinuums verdeutlichen die praktischen Aspekte. Eine Implementierung des klassischen AR-Szenarios, das EinfĂŒgen eines virtuellen Objektes in eine Live-Übertragung zeigt, wie mittels einer Differential Rendering Methode und einem selbstgebauten GerĂ€t zur Erfassung des einfallenden Lichts realistische Beleuchtung und Schatten erzielt werden können. Ein anderer Anwendungsbereich ist das EinfĂŒgen einer realen Person in eine kĂŒnstliche Szene. Hierzu werden zwei Methoden besprochen: Video-Billboards und eine interaktive 3D Rekonstruktion. Da die Implementierung von Mixed-Reality-Anwendungen Kentnisse und VerstĂ€ndnis einer ganzen Reihe von Technologien nebem dem eigentlichen Rendering voraus setzt, ist eine Diskussion der technischen Grundlagen ein wesentlicher Bestandteil dieser Arbeit. Dies ist notwenig, um die Entscheidungen fĂŒr bestimmte Designalternativen zu verstehen. Den Abschluss bildet eine Diskussion der Vor- und Nachteile von interaktivem Ray-Tracing fĂŒr Mixed Reality Anwendungen

    Not for designers: on the inadequacies of EU design law and how to fix it

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    Design rights represent an interesting example of how the EU legislature has successfully regulated an otherwise heterogeneous field of law. Yet this type of protection is not for all. The tools created by EU intervention have been drafted paying much more attention to the industry sector rather than to designers themselves. In particular, modern, digitally based, individual or small-sized, 3D printing, open designers and their needs are largely neglected by such legislation. The use of printing machinery to manufacture physical objects created digitally thanks to computer programs such as Computer-Aided Design (CAD) software has been in place for quite a few years, and it is actually the standard in many industrial fields, from aeronautics to home furniture. The change in recent years that has the potential to be a paradigm-shifting factor is a combination between the popularization of such technologies (price, size, usability, quality) and the diffusion of a culture based on access to and reuse of knowledge. We will call this blend Open Design. It is probably still too early, however, to say whether 3D printing will be used in the future to refer to a major event in human history, or instead will be relegated to a lonely Wikipedia entry similarly to “Betamax” (copyright scholars are familiar with it for other reasons). It is not too early, however, to develop a legal analysis that will hopefully contribute to clarifying the major issues found in current EU design law structure, why many modern open designers will probably find better protection in copyright, and whether they can successfully rely on open licenses to achieve their goals. With regard to the latter point, we will use Creative Commons (CC) licenses to test our hypothesis due to their unique characteristic to be modular, i.e. to have different license elements (clauses) that licensors can choose in order to adapt the license to their own needs
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