@article{HerderCohen2002, author = {Herder, Jens and Cohen, Michael}, title = {The Helical Keyboard: Perspectives for Spatial Auditory Displays and Visual Music}, series = {Journal of New Music Research}, volume = {31}, journal = {Journal of New Music Research}, number = {3}, pages = {269 -- 281}, year = {2002}, abstract = {Auditory displays with the ability to dynamically spatialize virtual sound sources under real-time conditions enable advanced applications for art and music. A listener can be deeply immersed while interacting and participating in the experience. We review some of those applications while focusing on the Helical Keyboard project and discussing the required technology. Inspired by the cyclical nature of octaves and helical structure of a scale, a model of a piano-style keyboard was prepared, which was then geometrically warped into a helicoidal configuration, one octave/revolution, pitch mapped to height and chroma. It can be driven by MIDI events, real-time or sequenced, which stream is both synthesized and spatialized by a spatial sound display. The sound of the respective notes is spatialized with respect to sinks, avatars of the human user, by default in the tube of the helix. Alternative coloring schemes can be applied, including a color map compatible with chromastereoptic eyewear. The graphical display animates polygons, interpolating between the notes of a chord across the tube of the helix. Recognition of simple chords allows directionalization of all the notes of a major triad from the position of its musical root. The system is designed to allow, for instance, separate audition of harmony and melody, commonly played by the left and right hands, respectively, on a normal keyboard. Perhaps the most exotic feature of the interface is the ability to fork one{\~A}­s presence, replicating subject instead of object by installing multiple sinks at arbitrary places around a virtual scene so that, for example, harmony and melody can be separately spatialized, using two heads to normalize the octave; such a technique effectively doubles the helix from the perspective of a single listener. Rather than a symmetric arrangement of the individual helices, they are perceptually superimposed in-phase, co-extensively, so that corresponding notes in different registers are at the same azimuth.}, language = {en} } @article{HerderWoerzbergerTwelkeretal.2002, author = {Herder, Jens and W{\"o}rzberger, Ralf and Twelker, Uwe and Albertz, Stefan}, title = {Use of Virtual Environments in the Promotion and Evaluation of Architectural Designs}, series = {Journal of the 3D-Forum Society}, volume = {16}, journal = {Journal of the 3D-Forum Society}, number = {4}, pages = {117 -- 122}, year = {2002}, abstract = {Virtual environments can create a realistic impression of an architectural space during the architectural design process, providing a powerful tool for evaluation and promotion during a project's early stages. In comparison to pre-rendered animations, such as walkthroughs based on CAD models, virtual environments can offer intuitive interaction and a more life like experience. Advanced virtual environments allow users to change realtime rendering features with a few manipulations, switching between different versions while still maintaining sensory immersion. This paper reports on an experimental project in which architectural models are being integrated into interactive virtual environments, and includes demonstrations of both the possibilities and limitations of such applications in evaluating, presenting and promoting architectural designs.}, language = {en} } @inproceedings{HerderCohen1997, author = {Herder, Jens and Cohen, Michael}, title = {Enhancing Perspicuity of Objects in Virtual Reality Environments}, series = {Proceedings, Second International Conference on Cognitive Technology}, booktitle = {Proceedings, Second International Conference on Cognitive Technology}, editor = {Gorayska, Barbara and Nehaniv, Chrystopher L. and Marsh, Jonathon P.}, publisher = {IEEE}, address = {Los Alamitos}, isbn = {0-8186-8084-9}, pages = {228 -- 237}, year = {1997}, abstract = {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).}, language = {en} } @inproceedings{SchmittHerderBhalla1997, author = {Schmitt, Lothar M. and Herder, Jens and Bhalla, Subhash}, title = {Information Retrieval and Database Architecture for Conventional Japanese Character Dictionaries}, series = {Proceedings, Second International Conference on Cognitive Technology}, booktitle = {Proceedings, Second International Conference on Cognitive Technology}, editor = {Gorayska, Barbara and Nehaniv, Chrystopher L. and Marsh, Jonathon P.}, publisher = {IEEE}, address = {Los Alamitos}, isbn = {0-8186-8084-9}, pages = {200 -- 217}, year = {1997}, abstract = {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.}, language = {en} } @inproceedings{MartensHerder1999, author = {Martens, William L. and Herder, Jens}, title = {Perceptual criteria for eliminating reflectors and occluders from the rendering of environmental sound}, series = {137th Regular Meeting of the Acoustical Society of America and the 2nd Convention of the European Acoustics Association}, booktitle = {137th Regular Meeting of the Acoustical Society of America and the 2nd Convention of the European Acoustics Association}, publisher = {Acoustical Society of America, European Acoustics Association}, address = {Berlin}, year = {1999}, abstract = {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.}, language = {en} } @inproceedings{MartensHerderShiba1999, author = {Martens, William L. and Herder, Jens and Shiba, Yoshiki}, title = {A filtering model for efficient rendering of the spatial image of an occluded virtual sound source}, series = {137th Regular Meeting of the Acoustical Society of America and the 2nd Convention of the European Acoustics Association}, booktitle = {137th Regular Meeting of the Acoustical Society of America and the 2nd Convention of the European Acoustics Association}, publisher = {Acoustical Society of America, European Acoustics Association}, address = {Berlin}, year = {1999}, abstract = {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}, language = {en} } @article{AmanoMatsushitaYanagawaetal.1998, author = {Amano, Katsumi and Matsushita, Fumio and Yanagawa, Hirofumi and Cohen, Michael and Herder, Jens and Martens, William and Koba, Yoshiharu and Tohyama, Mikio}, title = {A Virtual Reality Sound System Using Room-Related Transfer Functions Delivered Through a Multispeaker Array: the PSFC at the University of Aizu Multimedia Center}, series = {TVRSJ}, volume = {3}, journal = {TVRSJ}, number = {1}, publisher = {J-STAGE}, doi = {10.18974/tvrsj.3.1_1}, pages = {1 -- 12}, year = {1998}, abstract = {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.}, language = {en} } @incollection{CohenHerder1998, author = {Cohen, Michael and Herder, Jens}, title = {Symbolic representations of exclude and include for audio sources and sinks: Figurative suggestions of mute/solo \& cue and deafen/confide \& harken}, series = {Virtual Environments '98, Proceedings of the Eurographics Workshop}, booktitle = {Virtual Environments '98, Proceedings of the Eurographics Workshop}, editor = {G{\"o}bel, Martin and Landauer, J{\"u}rgen and Lang, Ulrich and Wapler, Matthias}, publisher = {Springer-Verlag}, address = {Stuttgart}, isbn = {3-211-83233-5}, doi = {10.1007/978-3-7091-7519-4_23}, pages = {235 -- 242}, year = {1998}, language = {en} } @inproceedings{AmanoMatsushitaYanagawaetal.1996, author = {Amano, Katsumi and Matsushita, Fumio and Yanagawa, Hirofumi and Cohen, Michael and Herder, Jens and Koba, Yoshiharu and Tohyama, Mikio}, title = {The Pioneer sound field control system at the University of Aizu Multimedia Center}, series = {RO-MAN '96 Tsukuba}, booktitle = {RO-MAN '96 Tsukuba}, publisher = {IEEE}, address = {Piscataway}, isbn = {0-7803-3253-9}, doi = {10.1109/ROMAN.1996.568887}, pages = {495 -- 499}, year = {1996}, abstract = {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.}, language = {en} } @inproceedings{HerderCohen1997, author = {Herder, Jens and Cohen, Michael}, title = {Sound Spatialization Resource Management in Virtual Reality Environments}, series = {ASVA'97 -- Int. Symp. on Simulation, Visualization and Auralization for Acoustic Research and Education}, booktitle = {ASVA'97 -- Int. Symp. on Simulation, Visualization and Auralization for Acoustic Research and Education}, address = {Tokyo}, pages = {407 -- 414}, year = {1997}, abstract = {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.}, language = {en} }