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In a virtual reality environment users are immersed in a scene with objects which might produce sound. The responsibility of a VR environment is to present these objects, but a system has only limited resources, including spatialization channels (mixels), MIDI/audio channels, and processing power. The sound spatialization resource manager controls sound resources and optimizes fidelity (presence) under given conditions. For that a priority scheme based on human psychophysical hearing is needed. Parameters for spatialization priorities include intensity calculated from volume and distance, orientation in the case of non-uniform radiation patterns, occluding objects, frequency spectrum (low frequencies are harder to localize), expected activity, and others. Objects which are spatially close together (depending on distance and direction) can be mixed. Sources that can not be spatialized can be treated as a single ambient sound source. Important for resource management is the resource assignment, i.e., minimizing swap operations, which makes it desirable to look-ahead and predict upcoming events in a scene. Prediction is achieved by monitoring objects’ speed and past evaluation values. Fidelity is contrasted for Zifferent kind of resource restrictions and optimal resource assignment based upon unlimited dynamic scene look-ahead. To give standard and comparable results, the VRML 2.0 specification is used as an application programmer interface. Applicability is demonstrated with a helical keyboard, a polyphonic MIDI stream driven animation including user interaction (user moves around, playing together with programmed notes). The developed sound spatialization resource manager gives improved spatialization fidelity under runtime constraints. Application programmers and virtual reality scene designers are freed from the burden of assigning and predicting the sound sources.
CAD/CAM techniques are increasingly used in dentistry for the design and fabrication of teeth estorations. Important concerns are the correction of articulation problems that existed before treatment and the prevention of treatment-generated problems. These require interactive evaluation of the occlusal surfaces of teeth during mastication. Traditional techniques based on the use of casts with mechanical articulators require manual adjustment of occlusal surfaces, which becomes impractical when hard restoration materials like porcelain are used; they are also time and labor consuming and provide little visual information. We present new visual tools and a related user interface for global articulation simulation, developed for the Intelligent Dental Care System project. The aim of the simulation is visual representation of characteristics relevant to the chewing process. The simulation is based on the construction of distance maps, which are visual representations of the distributions of the distances of points in a tooth to the opposite jaw. We use rasterizing graphics hardware for fast calculation of the distance maps. Distance maps are used for collision detection and for the derivation of various characteristics showing the distribution of load on the teeth and the chewing capability of the teeth. Such characteristics can be calculated for particular positions of the jaws; cumulative characteristics are used to describe the properties of jaw movement. This information may be used for interactive design of the occlusal surfaces of restorations and for jaw articulation diagnosis. We also demonstrate elements of a user interface that exploit metaphors familiar to dentists from everyday practice.
CAD/CAM techniques are increasingly used in dentistry for the design and fabrication of teeth restorations. Important concerns are the correction of articulation problems that existed beforetreatment and the prevention of treatment-generated problems. These require interactive evaluation of the occlusal surfaces of teeth during mastication. Traditional techniques based on the use of casts with mechanical articulators require manual adjustment of occlusal surfaces, which becomes impractical when hard restoration materials like porcelain are used; they are also time and labor consuming and provide little visual information. We present new visual tools and a related user interface for global articulation simulation, developed for the Intelligent Dental Care System project. The aim of the simulation is visual representation of characteristics relevant to the chewing process. The simulation is based on the construction of distance maps, which are visual representations of the distributions of the distances of points in a tooth to the opposite jaw. We use rasterizing graphics hardware for fast calculation of the distance maps. Distance maps are used for collision detection and for the derivation of various characteristics showing the distribution of load on the teeth and the chewing capability of the teeth. Such characteristics can be calculated for particular positions of the jaws; cumulative characteristics are used to describe the properties of jaw movement. This information may be used for interactive design of the occlusal surfaces of restorations and for jaw articulation diagnosis. We also demonstrate elements of a user interface that exploit metaphors familiar to dentists from everyday practice.
The PSFC, or Pioneer sound field control system, is a DSP-driven hemispherical 14-loudspeaker array, installed at the University of Aizu Multimedia Center. Collocated with a large screen rear-projection stereographic display the PSFC features realtime control of virtual room characteristics and direction of two separate sound channels, smoothly steering them around a configurable soundscape. The PSFC controls an entire sound field, including sound direction, virtual distance, and simulated environment (reverb level, room size and liveness) for each source. It can also configure a dry (DSP-less) switching matrix for direct directionalization. The PSFC speaker dome is about 14 m in diameter, allowing about twenty users at once to comfortably stand or sit near its sweet spot.
Dynamic characteristics of occlusion during lower jaw motion are useful in the diagnosis of jaw articulation problems and in computer-aided design/manufacture of teeth restorations. The Functionally Generated Path (FGP), produced as a surface which envelops the actual occlusal surface of the moving opponent jaw, can be used for compact representation of dynamic occlusal relations. In traditional dentistry FGP is recorded as a bite impression in a patient’s mouth. We propose an efficient computerized technique for FGP reconstruction and validate it through implementation and testing. The distance maps between occlusal surfaces of jaws, calculated for multiple projection directions and accumulated for mandibular motion, provide information for FGP computation. Rasterizing graphics hardware is used for fast calculation of the distance maps. Real-world data are used: the scanned shape of teeth and the measured motion of the lower jaw. We show applications of FGP to analysis of the occlusion relations and occlusal surface design for restorations.
Texturen können als Oberflächenstrukturen realer Objekt aufgefasst werden und sind Variationen in Farbe, Geometrie, Transparenz, usw.. Im Gegensatz zu Algorithmen für die künstliche Generierung von Texturen gibt es nur wenige Ansätze zu Textur-Synthese-Sprachen oder zu Hilfsmittel für die Textur-Beschreibung. Die bekannten Werkzeuge decken zudem jeweils nur Teilgebiete der Generierung ab. Mit HiLDTe (Hierachical Language for the Description of Textures) ist nun eine Sprache entwickelt worden, mit der möglichst alle bekannten Texturtypen beschrieben werden können. HiLDTe basiert auf einem am Fachgebiet GRIS entwickelten Texturmodell, in dem Texturen generische, eventuell komplex zusammengesetzte Objekte repräsentieren. Aufgabe dieser Arbeit war es nun, Konzepte für die Sprache HiLDTe zu entwickeln, eine entsprechende Grammatik aufzubauen und mit Hilfe der UNIX-Werkzeuge LEX und YACC einen Compiler zu implementieren, mit dem ein ausführbarer Zwischen-Code für die in HiLDTe spezifizierten Texturen erstellt wird.
The Common Lisp Interface Manager (CLIM) is used to develop graphical user interfaces for Lisp-basedapplications. With the prototype of the CLIM interface Builder (CLIB) the programmer can generate code for CLIM interactively. The developing process will be fast and less prone to errors. With this new tool, the interactive rapid prototyping reduces costs of a specification phase. Here we present the concept and first results of the prototype of CLIB.
CAD/CAM techniques are used increasingly in dentistry for design and fabrication of teeth restorations. An important issue is preserving occlusal contacts of teeth after restoration. Traditional techniques based on the use of casts with mechanical articulators require manual adjustment of occlusal surface, which becomes impractical when hard restoration materials like porcelain are used; they are also time and labor consuming. Most existing computer systems ignore completely such an articulation check, or perform the check at the level of a tooth and its immediate neighbors. We present a new mathematical model and a related user interface for global articulation simulation, developed for the Intelligent Dental Care System project. The aim of the simulation is elimination of the use of mechanical articulators and manual adjustment in the process of designing dental restorations and articulation diagnostic. The mathematical model is based upon differential topological modeling of the jawbs considered as a mechanical system. The user interface exploits metaphors that are familiar to dentists from everyday practice. A new input device designed specifically for use with articulation simulation is proposed.
We present a system that exploits mobile rotational tracking and photospherical imagery to allow users to share their environment with remotely connected peers “on the go.” We surveyed related interfaces and developed a unique groupware application that shares a mixed reality space with spatially-oriented live video feeds. Users can collaborate through realtime audio, video, and drawings in a virtual space. The developed system was tested in a preliminary user study, which confirmed an increase in spatial and situational awareness among viewers as well as reduction in cognitive workload. Believing that our system provides a novel style of collaboration in mixed reality environments, we discuss future applications and extensions of our prototype.
Multimediale Technologien werden in der Marktforschung immer stärker eingesetzt, um flexible und kostengünstige Studien durchzuführen. Im Innovationsprozess kann dabei auf die langjährigen Erfahrungen zurückgegriffen werden, die durch den Einsatz der Computersimulation in der technischen Produktentwicklung zustande gekommen sind. In sehr frühen Phasen des Innovationsprozesses können durch Einsatz der neuen Technologien die Markteinführungskonzepte für neue Produkte getestet werden. Die Applikationen der virtuellen Realität bieten ein einzigartiges Potential, neue Produkte einschlieï‚lich des Marketingkonzeptes zu testen, ohne dass dieses Produkt bereits physisch vorhanden sein muss. Am Beispiel eines Elementes des Marketingkonzeptes, der Preispolitik, zeigt die vorliegende Studie auf, welches Potential die virtuelle Kaufsituation von Produkten bietet. Der Fokus des Projektes liegt auf der interaktiven Produktpräsentation in einer virtuellen Umgebung, die in eine Online-Befragung mit zusätzlichen Werbefilmen eingebettet ist. Visuell hochwertige 3D-Produktpräsentationen versetzen den Probanden in eine virtuelle Einkaufsumgebung, die einem realen Szenario entspricht. Die virtuellen Produkte werden in mehreren Kaufentscheidungsrunden zu unterschiedlichen Preisen angeboten. Der Preisuntersuchung geht eine Präsentation ausgewählter Werbespots sowie eine produktbezogene Befragung voraus. Im Anschluss an die virtuellen Preisentscheidungen werden die Eindrücke sowie einige Kontrollgröen abgefragt. In weitergehenden Studien dieser Art können die Wirkungen mehrerer Marketing-Instrumente zu einem Zeitpunkt untersucht werden, in dem sich die Produkte noch im Entwicklungsprozess befinden. Auf diesem Weg lassen sich auch Wettbewerbsvorteile bestehender Produkte effizienter erkennen und nutzen. Mit den hoch entwickelten Computer- und Visualisierungstechnologien ist ein mächtiges Werkzeug entstanden, das bereits für kommerzielle Präsentationen und Produktstudien eingesetzt wird. Zukünftig kann es auch in Kombination mit Internetanwendungen und klassischen Methoden der Marktforschung zu einem sehr frühen Zeitpunkt umfassende Erkenntnisse über ein Produkt liefern.
With the virtual environment developed here, the characteristic
sound radiation patterns of musical instruments can be experienced
in real-time. The user may freely move around a musical instrument, thereby receiving acoustic and visual feedback in real-time. The perception of auditory and visual effects is intensified by the combination of acoustic and visual elements, as well as the option of user interaction. The simulation of characteristic sound radiation patterns is based on interpolating the intensities of a multichannel recording and offers a near-natural mapping of the sound radiation patterns. Additionally, a simple filter has been developed, enabling the qualitative simulation of an instrument’s characteristic sound radiation patterns to be easily implemented within real-time 3D applications. Both methods of simulating sound radiation patterns have been evaluated for a saxophone with respect to their functionality and validity by means of spectral analysis and an auditory experiment.
Virtual set environments for broadcasting become more sophisticated as well as the visual quality improves. Realtime interaction and production-specific visualization implemented through plugin mechanism enhance the existing systems like the 3DK. This work presents the integration of the Intersense IS-900 SCT camera tracking and 3D interaction into the 3DK virtual studio environment. The main goal of this work is the design of a virtual studio environment for post productions, which includes video output as well as media streaming formats such as MPEG-4. The systems allows high quality offline rendering during post production and 3D interaction by the moderator during the recording.
Virtual set environments for broadcasting become more sophisticated as well as the visual quality improves. Realtime interaction and production-specific visualization implemented through plugin mechanism enhance the existing systems like the virtual studio software 3DK. This work presents an algorithm which can dynamically manage textures of high resolution by prefetching them depending on their requirement in memory and map them on a procedural mesh in realtime. The main goal application of this work is the virtual representation of a flight over a landscape as part of weather reports in virtual studios and the interaction by the moderator.
High dynamic range environments maps based on still images or video streams are used for computer animation or interactive systems. The task of realistic light setup of scenes using captured environment maps might be eased as well as the visual quality improves. In this article, we discuss the light setting problem for virtual studio (tv) layout and system become more complex to handle this new feature of studio light capturing. The analysis of system requirements identifies the technical challenges.
Shadows in computer graphics are an important rendering aspect for spatial objects. For realtime computer applications such as games, it is essential to represent shadows as accurate as possible. Also, various tv stations work with virtual studio systems instead of real studio sets. Especially for those systems, a realistic impression of the rendered and mixed scene is important. One challenge, hence, is the creation of a natural shadow impression. This paper presents the results of an empirical study to compare the performance and quality of different shadow mapping methods. For this test, a prototype studio renderer was developed. A percentage closer filter (pcf) with a number of specific resolutions is used to minimize the aliasing issue. More advanced algorithms which generate smooth shadows like the percentage closer soft shadow (pcss) method as well as the variance shadow maps (vsm) method are analysed. Different open source apis are used to develop the virtual studio renderer, giving the benefit of permanent enhancement. The Ogre 3D graphic engine is used to implement the rendering system, benefiting from various functions and plugins. The transmission of the tracking data is accomplished with the vrpn server/client and the Intersense api. The different shadow algorithms are compared in a virtual studio environment which also casts real shadows and thus gives a chance for a direct comparison throughout the empirical user study. The performance is measured in frames per secon
For this study, an experimental vibrotactile feedback system was developed to help actors with the task of moving their arm to a certain place in a virtual tv studio under live conditions. Our intention is to improve interaction with virtual objects in a virtual set, which are usually not directly visible to the actor, but only on distant displays. Vibrotactile feedback might improve the appearance on tv because an actor is able to look in any desired direction (camera or virtual object) or to read text on a teleprompter while interacting with a virtual object. Visual feedback in a virtual studio lacks spatial relation to the actor, which impedes the adjustment of the desired interaction. The five tactors of the implemented system which are mounted on the tracked arm give additional information like collision, navigation and activation. The user study for the developed system shows that the duration for reaching a certain target is much longer in case no visual feedback is given, but the accuracy is similar. In this study, subjects reported that an activation signal indicating the arrival at the target of a drag & drop task was helpful. In this paper, we discuss the problems we encountered while developing such a vibrotactile display. Keeping these pitfalls in mind could lead to better feedback systems for actors in virtual studio environments.
Actors in virtual studio productions are faced with the challenge that they have to interact with invisible virtual objects because these elements are rendered separately and combined with the real image later in the production process. Virtual sets typically use static virtual elements or animated objects with predefined behavior so that actors can practice their performance and errors can be corrected in the post production. With the demand for inexpensive live recording and interactive TV productions, virtual objects will be dynamically rendered at arbitrary positions that cannot be predicted by the actor. Perceptive aids have to be employed to support a natural interaction with these objects. In our work we study the effect of haptic feedback for a simple form of interaction. Actors are equipped with a custom built haptic belt and get vibrotactile feedback during a small navigational task (path following). We present a prototype of a wireless vibrotactile feedback device and a small framework for evaluating haptic feedback in a virtual set environment. Results from an initial pilot study indicate that vibrotactile feedback is a suitable non-visual aid for interaction that is at least comparable to audio-visual alternatives used in virtual set productions.
Two high dynamic range HDR environments maps based on video streams from fish-eye lens cameras are used for generating virtual lights in a virtual set renderer. The task of realistic virtual light setup of scenes using captured environment maps might be eased as well as visual quality improves. We discuss the light setting problem for virtual studio tv productions which have mixed scenes of real objects, actors, virtual objects and virtual backgrounds. Benefits of hdr interactive light control are that the real light in the studio does not have to be remodeled and the artistic impression by using the light in the studio is also captured. An analysis of system requirements identifies technical challenges. We discuss the properties of a prototype system including test production.
Markerless talent tracking is widely used for interactions and animations within virtual environments. In a virtual (tv) studio talents could be overburden by interaction tasks because camera and text require extensive attention. We take a look into animations and inter- actions within a studio, which do not require any special attention or learning. We show the generation of an artificial shadow from a talent, which ease the keying process, where separation of real shadows from the background is a difficult task. We also demonstrate animations of footsteps and dust. Furthermore, capturing talents’ height can also be used to adjust the parameters of elements in the virtual environment, like the position and scaling of a virtual display. In addition to the talents, a rigid body was tracked as placeholder for graphics, easing the interaction tasks for a talent. Two test productions show the possibilities, which subtle animations offer. In the second production, the rendering was improved (shadows, filtering, normal maps, ...) and instead of using the rigid body to move an object (a flag), the animation was only controlled by the hand’s position.