TY - CHAP A1 - Bimber, Oliver T1 - HOLOGRAPHICS: Combining Holograms with Interactive Computer Graphics T2 - New Directions in Holography and Speckles N2 - Among all imaging techniques that have been invented throughout the last decades, computer graphics is one of the most successful tools today. Many areas in science, entertainment, education, and engineering would be unimaginable without the aid of 2D or 3D computer graphics. The reason for this success story might be its interactivity, which is an important property that is still not provided efficiently by competing technologies – such as holography. While optical holography and digital holography are limited to presenting a non-interactive content, electroholography or computer generated holograms (CGH) facilitate the computer-based generation and display of holograms at interactive rates [2,3,29,30]. Holographic fringes can be computed by either rendering multiple perspective images, then combining them into a stereogram [4], or simulating the optical interference and calculating the interference pattern [5]. Once computed, such a system dynamically visualizes the fringes with a holographic display. Since creating an electrohologram requires processing, transmitting, and storing a massive amount of data, today’s computer technology still sets the limits for electroholography. To overcome some of these performance issues, advanced reduction and compression methods have been developed that create truly interactive electroholograms. Unfortunately, most of these holograms are relatively small, low resolution, and cover only a small color spectrum. However, recent advances in consumer graphics hardware may reveal potential acceleration possibilities that can overcome these limitations [6]. In parallel to the development of computer graphics and despite their non-interactivity, optical and digital holography have created new fields, including interferometry, copy protection, data storage, holographic optical elements, and display holograms. Especially display holography has conquered several application domains. Museum exhibits often use optical holograms because they can present 3D objects with almost no loss in visual quality. In contrast to most stereoscopic or autostereoscopic graphics displays, holographic images can provide all depth cues—perspective, binocular disparity, motion parallax, convergence, and accommodation—and theoretically can be viewed simultaneously from an unlimited number of positions. Displaying artifacts virtually removes the need to build physical replicas of the original objects. In addition, optical holograms can be used to make engineering, medical, dental, archaeological, and other recordings—for teaching, training, experimentation and documentation. Archaeologists, for example, use optical holograms to archive and investigate ancient artifacts [7,8]. Scientists can use hologram copies to perform their research without having access to the original artifacts or settling for inaccurate replicas. Optical holograms can store a massive amount of information on a thin holographic emulsion. This technology can record and reconstruct a 3D scene with almost no loss in quality. Natural color holographic silver halide emulsion with grain sizes of 8nm is today’s state-of-the-art [14]. Today, computer graphics and raster displays offer a megapixel resolution and the interactive rendering of megabytes of data. Optical holograms, however, provide a terapixel resolution and are able to present an information content in the range of terabytes in real-time. Both are dimensions that will not be reached by computer graphics and conventional displays within the next years – even if Moore’s law proves to hold in future. Obviously, one has to make a decision between interactivity and quality when choosing a display technology for a particular application. While some applications require high visual realism and real-time presentation (that cannot be provided by computer graphics), others depend on user interaction (which is not possible with optical and digital holograms). Consequently, holography and computer graphics are being used as tools to solve individual research, engineering, and presentation problems within several domains. Up until today, however, these tools have been applied separately. The intention of the project which is summarized in this chapter is to combine both technologies to create a powerful tool for science, industry and education. This has been referred to as HoloGraphics. Several possibilities have been investigated that allow merging computer generated graphics and holograms [1]. The goal is to combine the advantages of conventional holograms (i.e. extremely high visual quality and realism, support for all depth queues and for multiple observers at no computational cost, space efficiency, etc.) with the advantages of today’s computer graphics capabilities (i.e. interactivity, real-time rendering, simulation and animation, stereoscopic and autostereoscopic presentation, etc.). The results of these investigations are presented in this chapter. KW - Erweiterte Realität KW - CGI KW - Hologramm KW - Projektionsapparat KW - Rendering KW - Scanning KW - Reconstruction KW - computer grafik KW - computer graphics Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-7365 ER - TY - CHAP A1 - Bimber, Oliver T1 - Projector-Based Augmentation T2 - Emerging Technologies of Augmented Reality: Interfaces & Design N2 - Projector-based augmentation approaches hold the potential of combining the advantages of well-establishes spatial virtual reality and spatial augmented reality. Immersive, semi-immersive and augmented visualizations can be realized in everyday environments – without the need for special projection screens and dedicated display configurations. Limitations of mobile devices, such as low resolution and small field of view, focus constrains, and ergonomic issues can be overcome in many cases by the utilization of projection technology. Thus, applications that do not require mobility can benefit from efficient spatial augmentations. Examples range from edutainment in museums (such as storytelling projections onto natural stone walls in historical buildings) to architectural visualizations (such as augmentations of complex illumination simulations or modified surface materials in real building structures). This chapter describes projector-camera methods and multi-projector techniques that aim at correcting geometric aberrations, compensating local and global radiometric effects, and improving focus properties of images projected onto everyday surfaces. KW - Erweiterte Realität KW - Virtuelle Realität KW - Projektionsverfahren KW - CGI KW - Bildbasiertes Rendering KW - Rendering KW - Projektor-Kamera Systeme KW - Multi-Projektor Systeme KW - projector-camera systems KW - multi-projector systems KW - spatial augmented reality Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-7353 ER - TY - THES A1 - Wieneke, Lars T1 - An analysis of productive user contributions in digital media applications for museums and cultural heritage. N2 - In a historical perspective, the relationship between digital media and the museum environment is marked by the role of museums as example use cases for the appli- cation of digital media. Today, this exceptional use as an often technology oriented application has changed and instead digital media have turned into an integral part of mediation strategies in the museum environment. Alongside with this shift not only an increasing professionalization of application development but also a grow- ing demand for new content can be observed. Comparable to its role as the main cost factor in the media industry, the production of content rises to a challenge for museums. In particular small and medium scale european museums with limited funding and an often low level of staff coverage face this new demand and strive therefore for alternative production resources. While productive user contributions can be seen as such an alternative resource, user contributions are at the same time a manifestation for a different mode of in- teracting with content. In contrast to the dominantly passive role of audiences as re- ceivers of information, productive contributions emerge as a mode of content ex- ploration and become in this regard influential for museum mediation strategies. As applications of user contributions in museums and cultural heritage are currently rather seldom, a broader perspective towards user contributions becomes necessary to understand its specific challenges, opportunities and limitations. Productive user contributions can be found in a growing number of applications on the Internet where they either complement or fully substitute corporate content production processes. While the Wikipedia1, an online encyclopedia written entirely by a group of users and open to contributions by all its users, is one of the most prominent examples for this practice, several more applications emerged or are be- ing developed. In consequence user contributions are about to become a powerful source for the production of content in digital media environments. N2 - Bis noch vor wenigen Jahren war das Verhältnis zwischen Museen und digitalen Medien durch die Nutzung von Museen als Fallstudien für die Anwendung neuer digitaler Medien geprägt. Im Gegensatz zu dieser frühen experimentellen und stark Technologie-orientierten Nutzung können digitale Medien heute als ein integraler Bestandteil der Vermittlungsstrategien (mediation strategies) im Museum betrachtet werden. Einhergehend mit dieser neuen Rolle kann nicht nur eine zunehmende Professionalisierung der Produktion digitaler Anwendung für den Museumsbereich beobachtet werden sondern auch ein stark wachsender Bedarf nach neuen Inhalten (content). Vergleichbar mit ihrer Rolle in der Medienindustrie stellen neue Inhalte auch im Museumsbereich einen der Hauptkostenfaktoren dar und werden besonders für kleinere und mittlere Museen mit begrenzten finanziellen Mitteln und dünner Per- sonaldecke zu einer zunehmenden Herausforderung. Von Nutzern erstellte Inhalte (user contributions) bieten sich als alternative Ressource für die Produktion von In- halten an. Gleichzeitig reflektiert die Produktion von Inhalten durch Nutzer eine andersartige Form der Auseinandersetzung mit Inhalten wie sie vor allem im Inter- net beobachtet werden kann. Im Gegensatz zum Modell des Zuschauers als pas- sivem Empfängern von Informationen kann die Produktion von Inhalten somit auch als Strategie zur Erschliessung von Themen verstanden werden und zeigt damit neuartige Perspektiven für die Vermittlung von Inhalten im Museum auf. Da der Einsatz derartiger Konzepte im Museumsbereich zur Zeit noch eine relativ geringe Verbreitung geniesst ist es notwendig, eine breitere Perspektive auf die pro- duktive Einbindung von Nutzern zu eröffnen um die besonderen Herausforderun- gen, Potentiale aber auch Einschränkungen ihrer Anwendung herauszuarbeiten. T2 - Eine Analyse produktiver Nutzer Beiträge in digitalen Medienanwendungen für Museen und kulturelles Erbe. KW - Neue Medien KW - Kulturerbe KW - Beteiligung KW - Content Management KW - User Generated Content KW - Rich Media Content KW - Inhalt KW - Content KW - Nutzerpartizipation KW - User-Created Content KW - Motivation KW - User created content KW - digital media KW - contribution management KW - content production Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20101214-15285 ER -