Jens Herder

Steering actors through a virtual set employing vibro-tactile feedback

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 vibro-tactile feedback during a small navigational task (path following). We present a prototype of a wireless vibro-tactile feedback device and a small framework for evaluating haptic feedback in a virtual set environment. Results from an initial pilot study indicate that vibro-tactile feedback is a suitable non-visual aid for interaction that is at least comparable to audio-visual alternatives used in virtual set productions.

Articulation simulation for an intelligent dental care system

Abstract 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 the occlusal surface, which becomes impractical when hard restoration materials like porcelain are used; they are also time- and labour-consuming. Most existing computer systems ignore completely such an articulation check, or perform the check at the level of a tooth and its immediate neighbours. 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 diagnostics. The mathematical model is based upon differential topological modelling of the jaws considered as a mechanical system. The user interface exploits metaphors that are familiar to dentist from everyday practice. A new input device designed specifically for use with articulation simulation is proposed.

Exploring spatial audio conferencing functionality in multiuser virtual environments (poster session)

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 users experience in multiuser virtual environments.

Large-area moderator tracking and demonstrational configuration of position based interactions for virtual studios

In this paper we introduce a system for tracking persons walking or standing on a large planar surface and for using the acquired data to easily configure position based interactions for virtual studio productions. The tracking component of the system, radarTRACK, is based on a laser scanner device capable of delivering interaction points on a large configurable plane. By using the device on the floor it is possible to use the delivered data to detect feet positions and derive the position and orientation of one or more users in real time. The second component of the system, named OscCalibrator, allows for the easy creation of multidimensional linear mappings between input and output parameters and the routing of OSC messages within a single modular design environment. We demonstrate the use of our system to flexibly create position-based interactions in a virtual studio environment.

The Helical Keyboard: Perspectives for Spatial Auditory Displays and Visual Music

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’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.

Tools and widgets for spatial sound authoring

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 such as limited sound spatialization channels can also be simulated.

Enhancing perspicuity of objects in virtual reality environments

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 users environment according to a dynamic priority evaluation of the information each object provides.

A filtering model for efficient rendering of the spatial image of an occluded virtual sound source

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. ...

Information retrieval and database architecture for conventional Japanese character dictionaries

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 individual phases in the design of a multi-dimensional language database based upon different computer software technologies are investigated in regard to the underlying cycle. The methods used in the design of a multi-dimensional language database include the use of UNIX software tools, classical database methods as well as the use of search engines based upon full text search. Several directions of application and extension for multi-dimensional language databases are discussed.

The Pioneer sound field control system at the University of Aizu Multimedia Center

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.