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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 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).
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
Digital broadcasting enables interactive \sc tv studios with virtual set environments. This presentation reviews current technology and describes the requirements for such systems. Interoperability over the production, streaming, and viewer levels requires open interfaces. As the technology allow more interaction, it becomes inherent difficult to control the quality of the viewers experience.
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.
The audio design for virtual environments includes simulation of acoustical room properties besides specifing sound sources and sinks and their behavior. Virtual environments supporting room reverberation not only gain realism but also provide additional information to the user about surrounding space. Catching the different sound properties by the different spaces requires partitioning the space by the properties of aural spaces. We define soundscape and aural attributes as an application and multimedia content interface. Calculated data on an abstract level is sent to spatialization backends. Part of this research was the implementation of a device driver for the Roland Sound Space Processor. This device not only directionalizes sound sources, but also controls room effects like reverberation.
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.
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.
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 oneÃs 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.
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.
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.
In today’s market research mechanisms multi modal technologies are significant tools to perform flexible and price efficient studies for not only consumer products but also consumer goods. Current appraisal mechanisms in combination with applied computer graphics can improve the assessment of a product’s launch in the very early design phase or an innovation process. The combination of online questionnaires, Virtual Reality (VR) applications and a database management system offers a powerful tool to let a consumer judge products as well as innovated goods even without having produced a single article. In this paper we present an approach of consumer good studies consisting of common as well as interactive VR product presentations and online questionnaires bases on a bidirectional database management solution to configure and manage numerous studies, virtual sets, goods and participants in an effective way to support the estimation of the received data. Non-programmers can create their test environment including a VR scenario very quickly without any effort. Within the extensive knowledge of consumer goods, marketing instruments can be defined to shorten and improve the rollout process in the early product stages.
The presentation of virtual environments in real time has always been a demanding task. Specially designed graphics hardware is necessary to deal with the large amounts of data these applications typically produce. For several years the chipsets that were used allowed only simple lighting models and fixed algorithms. But recent development has produced new graphics processing units (GPUs) that are much faster and more programmable than their predecessors. This paper presents an approach to take advantage of these new features. It uses a video texture as part of the lighting calculations for the passenger compartment of a virtual train and was run on the GPU of a recent PC graphics card. The task was to map the varying illumination of a filmed landscape onto the virtual objects and also onto another video texture (showing two passengers), thereby enhancing the realism of the scene.
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.
This paper explores the tensions in team creativity. The tensions in team creativity are based on a tension between originality and effectiveness in the standard definition of creativity. To display the tensions in team creativity, the value square (“Wertequadrat”) developed by Schulz von Thun (1998) is used which balances a value with its countervalue. The author identifies tensions for cohesion, consensus and conformity. Cohesion is described as a tension between team diversity and team safety, consensus as a tension between constructive controversy and participatory decision-making and conformity as a tension between support for innovation and task orientation. Finally, the connection of individual and team creativity is described as an interplay between solitary and interactive components.
Using spatial audio successfully for augmented reality (AR) applications is a challenge, but is awarded with an improved user experience. Thus, we have extended the AR/VR framework \sc Morgan with spatial audio to improve users orientation in an AR application. In this paper, we investigate the users’ capability to localize and memorize spatial sounds (registered with virtual or real objects). We discuss two scenarios. In the first scenario, the user localizes only sound sources and in the second scenario the user memorizes the location of audio-visual objects. Our results reflect spatial audio performance within the application domain and show which technology pitfalls still exist. Finally, we provide design recommendations for spatial audio AR environments.
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.
Virtual TV studios use actor tracking systems for resolving the occlusion of computer graphics and studio camera image. The actor tracking delivers the distance between actor and studio camera. We deploy a photonic mixing device, which captures a depth map and a luminance image at low resolution. The renderer engines gets one depth value per actor using the OSC protocol. We describe the actor recognition algorithm based on the luminance image and the depth value calculation. We discuss technical issues like noise and calibration.
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
Mobile live video streaming is becoming an increasingly popular form of interaction both in social media and remote collaboration scenarios. However, in most cases the streamed video does not take mobile devices' spatial data into account (e.g., the viewers do not know the spatial orientation of a streamer), or use such data only in specific scenarios (e.g., to navigate around a spherical video stream).
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.
Vibrotactile feedback via body-worn vibrating belts is a common means of direction signalization - e.g. for navigational tasks. Consequently such feedback devices are used to guide blind or visually impaired people but can also be used to support other wayfinding tasks - for instance, guiding actors in virtual studio productions. Recent effort has been made to simplify this task by integrating vibrotactile feedback into virtual studio applications. In this work we evaluate the accuracy of an improved direction signalization technique, utilizing a body-worn vibrotactile belt with a limited number of tactors, and compare it to other work. The results from our user study indicate that it is possible to signalize different directions accurately, even with a small number of tactors spaced by 90°.
In this paper we describe the design of a virtual reality simulator for traditional intuitive archery. Traditional archers aim without a target figure. Good shooting results require an excellent body-eye coordination that allows the user to perform identical movements when drawing the bow. Our simulator provides a virtual archery experience and supports the user to learn and practice the motion sequence of traditional archery in a virtual environment. We use an infrared tracking system to capture the user’s movements in order to correct his movement. To provide a realistic haptic feedback a real bow is used as interaction device. Our system provides a believable user experience and supports the user to learn how to shoot in the traditional way. Following a user-centered iterative design approach we developed a number of prototypes and evaluated them for refinement in sequent iteration cycles. For illustration purposes we created a short video clip in our virtual studio about this project that presents the main ideas in an informative yet entertaining way.
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.
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
This article presents a new approach of integrating tangible user feedback in todays virtual TV studio productions. We describe a tangible multitouch planning system, enabling multiple users to prepare and customize scene flow and settings. Users can collaboratively view and interact with virtual objects by using a tangible user interface on a shared multitouch surface. The in a 2D setting created TV scenes are simultaneously rendered on an external monitor, using a production/target renderer in 3D. Thereby the user experiences a closer reproduction of a final production. Subsequently, users are able to join together the scenes into one complex plot. Within the developing process, a video prototype of the system shows the user interaction and enables early reviews and evaluations. The requirement analysis is based on expert interviews.
In this paper we describe a prototypical system for live musical performance in a virtual studio environment. The performer stands in front of the studio camera and interacts with an infrared-laser-based multi-touch device. The final TV image shows the performer interacting with a virtual screen which is augmented in front of herself. To overcome the problem of the performer not seeing this virtual screen in reality, we use a special hexagonal grid to facilitate the performer's awareness of this novel Theremin-like virtual musical instrument.
This paper presents a tracking of parts of a human body in a virtual TV studio environment. The tracking is based on a depth camera and a HD studio camera and aims at a realistic interaction between the actor and the computer generated environment. Stereo calibration methods are used to match corresponding pixels of both cameras (HD color and depth image). Hence the images were rectified and column aligned. The disparity is used to correct the depth image pixel by pixel. This image registration results in row and column aligned images where ghost regions are in the depth image resulting from occlusion. Both images are used to generate foreground masks with chroma and depth keying. The color image is taken for skin color segmentation to determine and distinguish the actor’s hands and face. In the depth image the flesh colored regions were used to determine their spatial position. The extracted positions were augmented by virtual objects. The scene is rendered correctly with virtual camera parameters which were calculated from the camera calibration parameters. Generated computer graphics with alpha value are combined with the HD color images. This compositing shows interaction with augmented objects for verification. The additional depth information results in changing the size of objects next to the hands when the actor moves around.
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.
This paper presents a mobile approach of integrating tangible user feedback in today’s virtual TV studio productions. We describe a tangible multitouch planning system, enabling a single user to prepare and customize scene flow and settings. Users can view and interact with virtual objects by using a tangible user interface on a capacitive multitouch surface. In a 2D setting created TV scenes are simultaneously rendered as separate view using a production/target renderer in 3D. Thereby the user experiences a closer reproduction of a final production and set assets can be reused. Subsequently, a user can arrange scenes on a timeline while maintaining different versions/sequences. The system consists of a tablet and a workstation, which does all application processing and rendering. The tablet is just an interface connected via wireless LAN.
This paper presents an approach to integrate non-visual user feedback in today's virtual tv studio productions. Since recent studies showed that systems providing vibro-tactile feedback are not sufficient for replacing the common visual feedback, we developed an audio-based solution using an in ear headphone system, enabling a talent to move, avoid and point to virtual objects in a blue or green box. The system consists of an optical head tracking system, a wireless in ear monitor system and a workstation, which performs all application and audio processing. Using head related transfer functions, the talent gets directional and distance cues. Past research showed, that generating reflections of the sounds and simulating the acoustics of the virtual room helps the listener to conceive the acoustical feedback, we included this technique as well. In a user study with 15 participants the performance of the system was evaluated.
Virtual (tv) studios gain much more acceptance through improvements in computer graphics and camera tracking. Still commercial studios cannot have full interaction between actors and virtual scene because actors data are not completely digital available as well as the feedback for actors is still not sufficient. Markerless full body tracking might revolutionize virtual studio technology as it allows better interaction between real and virtual world. This article reports about using a markerless actor tracking in a virtual studio with a tracking volume of nearly 40 cubic meter enabling up to three actors within the green box. The tracking is used for resolving the occlusion between virtual objects and actors so that the Tenderer can output automatically a mask for virtual objects in the foreground in case the actor is behind. It is also used for triggering functions scripted within the Tenderer engine, which are attached to virtual objects, starting any kind of action (e.g., animation). Last but not least the system is used for controlling avatars within the virtual set. All tracking and rendering is done within a studio frame rate of 50 Hz with about 3 frames delay. The markerless actor tracking within virtual studios is evaluated by experts using an interview approach. The statistical evaluation is based on a questionnaire.
The late immersion of multi-touch sensitive displays enables the use of tangibles on multi-touch screens. There a several wide spread and/or sophisticated solutions to fulfill this need but they seem to have some flaws. One popular system at the time of writing is an overlay frame that can be placed on a normal display with the corresponding size. The frame creates a grid with infrared light emitting diodes. The disruption of this grid can be detected and messages with the positions are sent via usb to a connected computer. This system is quite robust in matters of ambient light insensitivity and also fast to calibrate. Unfortunately it is not created with the recognition of tangibles in mind and printed patterns can not be resolved. This article summarizes an attempt to create fiducials that are recognized by an infrared multi-touch frame as fingers. Those false fingers are checked by a software for known patterns. Once a known pattern (= fiducial) has been recognized its position and orientation are send with the finger positions towards the interactive software. The usability is tested with an example application where tangibles and finger touches are used in combination.