@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{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} }