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Virtual sets have evolved from computer-generated, prerendered 2D backgrounds to realtime, responsive 3D computer graphics and are nowadays standard repertoire of broadcasting divisions. The graphics, which are combined with real video feed becoming moresophisticated, real looking and more responsive. We will look at the recent developments and suggest further developments like integration of spatial audio into the studio production and generating interactive media streams. Educational institutes recognize the demands of the rising media industry and established new courses on media technology like the Duesseldorf University of Applied Sciences.
Distance and Room Effects Control for the PSFC, an Auditory Display using a Loudspeaker Array
(2000)
The Pioneer Sound Field Controller (PSFC), a loudspeaker array system, features realtime configuration of an entire sound field,including sound source direction, virtual distance, and context of simulated environment (room characteristics: room size and liveness)for each of two sound sources. In the PSFC system, there is no native parameter to specify the distance between the sound source and sound sink (listener) and also no function to control it directrly. This paper suggests the method to control virtual distance using basic parameters: volume, room size and liveness. The implementation of distance cue is an important aspect of 3D sounds. Virtual environments supporting room effects like reverberation not only gain realism but also provide additional information to users about surrounding space. The context switch of different aural attributes is done by using an API of the Sound Spatialization Framework. Therefore, when the sound sink move through two rooms, like a small bathroom and a large living room, the context of the sink switches and different sound is obtained.
A chatspace was developed that allows conversation with 3D sound using networked streaming in a shared virtual environment. The system provides an interface to advanced audio features, such as a "whisper function" for conveying a confided audio stream. This study explores the use of spatial audio to enhance a user's experience in multiuser virtual environments.
A filtering model for efficient rendering of the spatial image of an occluded virtual sound source
(1999)
Rendering realistic spatial sound imagery for complex virtual environments must take into account the effects of obstructions such as reflectors and occluders. It is relatively well understood how to calculate the acoustical consequence that would be observed at a given observation point when an acoustically opaque object occludes a sound source. But the interference patterns generated by occluders of various geometries and orientations relative to the virtual source and receiver are computationally intense if accurate results are required. In many applications, however, it is sufficient to create a spatial image that is recognizable by the human listener as the sound of an occluded source. In the interest of improving audio rendering efficiency, a simplified filtering model was developed and its audio output submitted to psychophysical evaluation. Two perceptually salient components of occluder acoustics were identified that could be directly related to the geometry and orientation of a simple occluder. Actual occluder impulse responses measured in an anechoic chamber resembled the responses of a model incorporating only a variable duration delay line and a low-pass filter with variable cutoff frequency.
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 practical system has only limited resources, including spatialization channels (mixels), MIDI/audio channels, and processing power. A sound spatialization resource manager, introduced in this thesis, controls sound resources and optimizes fidelity (presence) under given conditions, using a priority scheme based on psychoacoustics. Objects which are spatially close together can be coalesced by a novel clustering algorithm, which considers listener localization errors. Application programmers and VR scene designers are freed from the burden of assigning mixels and predicting sound source locations. The framework includes an abstract interface for sound spatialization backends, an API for the VR environments, and multimedia authoring tools.
Level-of-detail is a concept well-known in computer graphics to reduce the number of rendered polygons. Depending on the distance to the subject (viewer), the objects’ representation is changed. A similar concept is the clustering of sound sources for sound spatialization. Clusters can be used to hierarchically organize mixels and to optimize the use of resources, by grouping multiple sources together into a single representative ource. Such a clustering process should minimize the error of position allocation of
elements, perceived as angle and distance, and also differences between velocity relative to the sink (i.e., Doppler shift). Objects with similar direction of motion and speed (relative to sink) in the same acoustic resolution cone and with similar distance to a sink can be grouped together.
A module for soundscape monitoring and visualizing resource management processes was extended for presenting clusters, generated by a novel sound source clustering algorithm. This algorithm groups multiple sound sources together into a single representative source, considering localization errors depending on listener orientation. Localization errors are visualized for each cluster using resolution cones. Visualization is done in runtime and allows understanding and evaluation of the clustering algorithm.
A module for soundscape monitoring and visualizing resource management processes was extended for presenting clusters, generated by a novel sound source clustering algorithm. This algorithm groups multiple sound sources together into a single representative source, considering localization errors depending on listener orientation. Localization errors are visualized for each cluster using resolution cones. Visualization is done in runtime and allows understanding and evaluation of the clustering algorithm.
A filtering model for efficient rendering of the spatial image of an occluded virtual sound source
(1999)
Rendering realistic spatial sound imagery for complex virtual environments must take into account the effects of obstructions such as reflectors and occluders. It is relatively well understood how to calculate the acoustical consequence that would be observed at a given observation point when an acoustically opaque object occludes a sound source. But the interference patterns generated by occluders of various geometries and orientations relative to the virtual source and receiver are computationally intense if accurate results are required. In many applications, however, it is sufficient to create a spatial image that is recognizable by the human listener as the sound of an occluded source. In the interest of improving audio rendering efficiency, a simplified filtering model was developed and its audio output submitted to psychophysical evaluation. Two perceptually salient components of occluder acoustics were identified that could be directly related to the geometry and orientation of a simple occluder. Actual occluder impulse responses measured in an anechoic chamber resembled the responses of a model incorporating only a variable duration delay line and a low-pass filter with variable cutoff frequenc
Given limited computational resources available for the rendering of spatial sound imagery, we seek to determine effective means for choosing whatcomponents of the rendering will provide the most audible differences in the results. Rather than begin with an analytic approach that attempts to predict audible differences on the basis of objective parameters, we chose to begin with subjective tests of how audibly different the rendering result may be heard to be when that result includes two types of sound obstruction: reflectors and occluders. Single-channel recordings of 90 short speech sounds were made in an anechoic chamber in the presence and absence of these two types of obstructions, and as the angle of those obstructions varied over a 90 degree range. These recordings were reproduced over a single loudspeaker in that anechoic chamber, and listeners were asked to rate how confident they were that the recording of each of these 90 stimuli included an obstruction. These confidence ratings can be used as an integral component in the evaluation function used to determine which reflectors and occluders are most important for rendering.
Cyberspatial audio applications are distinguished from the broad range of spatial audio applications in a number of important ways that help to focus this review. Most significant is that cyberspatial audio is most often designed to be responsive to user inputs. In contrast to non-interactive auditory displays, cyberspatial auditory displays typically allow active exploration of the virtual environment in which users find themselves. Thus, at least some portion of the audio presented in a cyberspatial environment must be selected, processed, or otherwise rendered with minimum delay relative to user input. Besides the technological demands associated with realtime delivery of spatialized sound, the type and quality of auditory experiences supported are also very different from those associated with displays that support stationary sound localization.
The Sound Spatialization Framework is a C++ toolkit and development environment for providing advanced sound spatialization for virtual reality and multimedia applications. The Sound Spatialization Framework provides many powerful display and user-interface features not found in other sound spatialization software packages. It provides facilities that go beyond simple sound source spatialization: visualization and editing of the soundscape, multiple sinks, clustering of sound sources, monitoring and controlling resource management, support for various spatialization backends, and classes for MIDI animation and handling.
This dissertation, written for the course Master of European Social Policy Analysis – National University of Ireland Maynooth - , shows the context or so-called framework within which the medical social work service in two different welfare states: Ireland and Germany operates. This means the societal context as a whole, the health system in general (macro-level) and the hospital setting (mezzo-level) in particular. The idea of this publication is to give a short overview of the historic development of medical social work (micro-level) in Ireland and Germany and some background information about what medical social work is. The time frame examined starts from the 1980s up to present. The main questions to be answered are: What are the interdependencies between the macro-, mezzo- and micro-level? Have changes in the health system in general and the hospitals in particular influenced medical social work and if so how? What are the similarities and differences in the two countries?
The Sound Spatialization Framework is a C++ toolkit and development environment for providing advanced sound spatialization for virtual reality and multimedia applications. The Sound Spatialization Framework provides many powerful display and user-interface features not found in other sound spatialization software packages. It provides facilities that go beyond simple sound source spatialization: visualization and editing of the soundscape, multiple sinks, clustering of sound sources, monitoring and controlling resource management, support for various spatialization backends, and classes for MIDI animation and handling.
Keywords:
sound spatialization, resource management, virtual environments, spatial sound authoring, user interface design, human-machine interfaces
The PSFC, or Pioneer Sound Field Controller, is a DSP-driven hemispherical loudspeaker array, installed at the University of Aizu Multimedia Center. The PSFC features realtime manipulation of the primary components of sound spatialization for each of two audio sources located in a virtual environment, including the content (apparent direction and distance) and context (room characteristics: reverberation level, room size and liveness). In an alternate mode, it can also direct the destination of the two separate input signals across 14 loudspeakers, manipulating the direction of the virtual sound sources with no control over apparent distance other than that afforded by source loudness (including no simulated environmental reflections or reverberation). The PSFC speaker dome is about 10 m in diameter, accommodating about fifty simultaneous users, including about twenty users comfortably standing or sitting near its ``sweet spot,'' the area in which the illusions of sound spatialization are most vivid. Collocated with a large screen rear-projection stereographic display, the PSFC is intended for advanced multimedia and virtual reality applications.
A Sound Spatialization Server for a Speaker Array as an Integrated Part of a Virtual Environment
(1998)
Spatial sound plays an important role in virtual reality environments, allowing orientation in space, giving a feeling of space, focusing the user on events in the scene, and substituting missing feedback cues (e.g., force feedback). The sound spatialization framework of the University of Aizu, which supports number of spatialization backends, has been extended to include a sound spatialization server for a multichannel loudspeaker array (Pioneer Sound Field Control System). Our goal is that the spatialization server allows easy integration into virtual environments. Modeling of distance cues, which are essential for full immersion, is discussed. Furthermore, the integration of this prototype into different applications allowed us to reveal the advantages and problems of spatial sound for virtual reality environments.
Education at the University of Aizu is focussed upon computer science. Besides being the subject matter of many courses, however, the computer also plays a vital role in the educational process itself, both in the distribution of instructional media, and in providing students with valuable practical experience. All students have unlimited access (24-hours-a-day) to individual networked workstations, most of which are multimedia-capable (even video capture is possible in two exercise rooms). Without software and content tailored for computer-aided instruction, the hardware becomes an expensive decoration. In any case, there is a need to better educate the instructors and students in the use of the equipment. In the interest of facilitating effective, collaborative use of network-based computers in teaching, this article explores the impact that a network environment can have on such activities. First, as a general overview, and to examine the motivation for the use of a network environment in teaching, this article reviews a range of different styles of collaboration. Then the article shows what kind of tools are available for use, within the context of what has come to be called Computer-Supported Cooperative Work (CSCW).
Broader use of virtual reality environments and sophisticated animations spawn a need for spatial sound. Until now, spatial sound design has been based very much on experience and trial and error. Most effects are hand-crafted, because good design tools for spatial sound do not exist. This paper discusses spatial sound authoring and its applications, including shared virtual reality environments based on VRML. New utilities introduced by this research are an inspector for sound sources, an interactive resource manager, and a visual soundscape manipulator. The tools are part of a sound spatialization framework and allow a designer/author of multimedia content to monitor and debug sound events. Resource constraints like limited sound spatialization channels can also be simulated.
In an information-rich Virtual Reality (VR) environment, the user is immersed in a world containing many objects providing that information. Given the finite computational resources of any computer system, optimization is required to ensure that the most important information is presented to the user as clearly as possible and in a timely fashion. In particular, what is desired are means whereby the perspicuity of an object may be enhanced when appropriate. An object becomes more perspicuous when the information it provides to the user becomes more readily apparent. Additionally, if a particular object provides high-priority information, it would be advantageous to make that object obtrusive as well as highly perspicuous. An object becomes more obtrusive if it draws attention to itself (or equivalently, if it is hard to ignore). This paper describes a technique whereby objects may dynamically adapt their representation in a user's environment according to a dynamic priority evaluation of the information each object provides. The three components of our approach are:
- an information manager that evaluates object information priority,
- an enhancement manager that tabulates rendering features associated with increasing object perspicuity and obtrusion as a function of priority, and
- a resource manager that assigns available object rendering resources according to features indicated by the enhancement manager for the priority set for each object by the information manager.
We consider resources like visual space (pixels), sound spatialization channels (mixels), MIDI/audio channels, and processing power, and discuss our approach applied to different applications. Assigned object rendering features are implemented locally at the object level (e.g., object facing the user using the billboard node in VRML 2.0) or globally, using helper applications (e.g., active spotlights, semi-automatic cameras).
Information Retrieval and Database Architecture for Conventional Japanese Character Dictionaries
(1997)
The cycle of abstraction-reconstruction which occurs as a fundamental principle in the development of culture and in cognitive processes is described and analyzed. This approach leads to recognition of boundary conditions for and directions of probable development of cognitive tools. It is shown how the transition from a conventional Japanese-English character dictionary to a multi-dimensional language database is an instance of such an abstraction-reconstruction cycle. The different phases of the design of a multi-dimensional language database based upon different computer software technologies are properly placed in this cycle. The methods used include the use of UNIX software tools, classical database methods as-well-as the use of search engines based upon full text search in this process. Several directions of application and extension for a multi-dimensional language database are discussed from the general point of view of an abstraction-reconstruction cycle.
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.
Design of a Helical Keyboard
(1996)
Inspired by the cyclical nature of octaves and helical structure of a scale (Shepard, '82 and '83), we prepared a model of a piano-style keyboard (prototyped in Mathematica), which was then geometrically warped into a left-handed helical configuration, one octave/revolution, pitch mapped to height. The natural orientation of upper frequency keys higher on the helix suggests a parsimonious left-handed chirality, so that ascending notes cross in front of a typical listener left to right. Our model is being imported (via the dxf file format) into (Open Inventor/)VRML, where it can be driven by MIDI events, realtime or sequenced, which stream is both synthesized (by a Roland Sound Module), and spatialized by a heterogeneous spatial sound backend (including the Crystal River Engineering Acoustetron II and the Pioneer Sound Field Control speaker-array System), so that the sound of the respective notes is directionalized with respect to sinks, avatars of the human user, by default in the tube of the helix. This is a work-in-progress which we hope to be fully functional within the next few months.
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.
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 task of the Center for Language Research is to provide content-based English language instruction for students of computer science and engineering. As such, we find ourselves at the confluence of many of the streams currently running through the English Language Teaching profession, including English for Science and Technology (EST), English for Academic Purposes (EAP), English for Specific Purposes (ESP), Computer-assisted language learning (CALL), content-based instruction, and multimedia applications in foreign language pedagogy. This paper describes our initial attempts to construct a number of World Wide Web pages where students will be able to study EST, EAP, and computer science topics on their own in a multimedia environment.
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.
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.
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.