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Graf, Holger; Stork, André

CAE/VR Integration - A Path to Follow? A Validation Based on Industrial Use

2017

Zoltay Paprika, Zita (Ed.) et al.: ECMS 2017 : 31st European Conference on Modelling and Simulation, pp. 436-445

European Conference on Modelling and Simulation (ECMS) <31, 2017, Budapest, Hungary>

Numerical simulations have become crucial during the product development process (PDP) for predicting and validating different properties of new products as well as the simulation of various kinds of natural phenomena. Especially the engineering domain (CAE - Computer Aided Engineering), is seeking for new ICT solutions to cover broad ranges of physical simulations. Virtual Reality (VR) has matured in the past allowing a rapid consolidation of information and decision-making through visualization and experience. These new man machine interfaces offer advanced interaction possibilities with the digital domain and allow engineers to variate over several hypothesis. This enlightened ideas to deploy VR for "what-if-scenarios" also in the CAE domain. However, while CAD/VR integration has been sufficiently researched, the integration of CAE into VR is still facing a long road ahead. Despite recent criticism that the application of VR technology has been considered unnecessary in CAE, this paper aims to refute this by presenting methodologies for linear static FEM analysis allowing "what-if-scenarios" within interactive environments. It validates the elaborated methodologies and advantages of VR front ends by an evaluation performed within industrial engineering departments.

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Guidi, Gabriele; Scopigno, Roberto; Torres, Juan Carlos; Graf, Holger

2015 Digital Heritage International Congress. Volume 1

2015

New York : The Institute of Electrical and Electronics Engineers (IEEE), 2015

Digital Heritage International Congress (DH) <2015, Granada, Spain>

Digitization and Acquisition - Photogrammetry & image-based modeling - 3D scanning & digitization (laser, structured light, motion capture, etc.) - Remote sensing and Aerial Laser Scanning (ALS) - GNSS (GPS, GLONASS, Galileo) - Advanced 2Ddocument scanning - Low-cost & gaming 3D input - Ultra-high resolution & HDR photography - Terahertz, Infrared, UV & X-ray imaging - Advanced sensors research - Heritage diagnostics Computer Graphics and Interaction - Immersive and Active/Passive stereo-displays - Augmented displays - Real + virtual worlds (mixed/augmented reality) - Virtualization of other senses (touch, taste, smell, sound) - Haptic & Multimodal interaction - Distributed VR - Local/remote rendering - Innovative interaction systems - Tools for Storytelling and Serious Games - Tools for multimedia or museums installations - Usability, effectiveness and interface design - Visual simulation of materials - Emerging visualization technologies - Surface reconstruction from sampled 3D data - Multiresolution 3D modelling and rendering methods - Interactive visualization of very large 3D models in low-end and mobile devices

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Guidi, Gabriele; Scopigno, Roberto; Torres, Juan Carlos; Graf, Holger

2015 Digital Heritage International Congress. Volume 2

2015

New York : The Institute of Electrical and Electronics Engineers (IEEE), 2015

Digital Heritage International Congress (DH) <2015, Granada, Spain>

Analysis and Interpretation - Historic Document Analysis - Remote Sensing Analysis (including visible, multispectral and radar images) - Finite element, structural and other analyses - 3D modeling (CAD-based and reality-based) - Building Information Modeling (BIM) - Virtual Reconstruction Issues - Realism and Interpretation in CH - 3D, multimedia and GIS repositories, platforms, & info systems - Digital Curation and Museology - Virtual GIS and Mapping tools - Integrated interpretation of diagnostic sensors Theory, Methodologies, Preservation and Standards - Metadata Handling & Management - Digital libraries - Heritage Commons - Cultural Analytics - Heritage at Risk - Cognitive Sciences and Interaction - Digital Humanities - Text Markup / Analysis - Born digital content issues - Digital Rights Management - Trusted digital repositories / OAIS - Institutional Repositories - Semantic Web in CH - New Economical Models for Digital Heritage - Long term storage and persistence - Requirements and policies for Preservation - Data formats and compression for preservation Digital Heritage Projects and Applications - Integrated solutions and best practices in: - Virtual documentation - Virtual heritage conservation - Virtual restoration - Virtual archaeology - Virtual museums - Virtual Exhibitions - Serious Games for heritage - Collaborative environments - Internet technologies and social media - Digital documentation for conservation

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Graf, Holger; Keil, Jens; Pagano, Alfonsina; Pescarin, Sofia

A Contextualized Educational Museum Experience: Connecting Objects, Places and Themes through mobile Virtual Museums

2015

Guidi, Gabriele (Ed.) et al.: 2015 Digital Heritage International Congress. Volume 1. New York: The Institute of Electrical and Electronics Engineers (IEEE), 2015, pp. 337-340

Digital Heritage International Congress (DH) <2015, Granada, Spain>

This paper presents the results of ongoing work realizing a mobile virtual museum that enables the connection between locally dispersed museums, collections and artefacts. The mobile application interconnects venues, objects and stories for an enhanced user experience and increased learnability inside the museum. It contextualizes information and reveals missing and hidden links between the digital replicas of the objects displayed in four different venues under one storyline. Within this context, we also provide a preliminary evaluation on how the mobile virtual museum could be used as support to indirect formal learning of young visitors, improving memorability.

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Yoon, Sang Min; Graf, Holger; Kuijper, Arjan

Hierarchical Image Representation using 3D Camera Geometry for Content-based Image Retrieval

2014

Engineering Applications of Artificial Intelligence, Vol.30 (2014), pp. 235-241

In this paper we present a hierarchical image representation methodology by clustering images with 3D camera geometry in order to efficiently retrieve the images according to user's viewpoint. The framework of our proposed technique is composed of two steps: first the visual correlation analysis between images in a large database is determined by the estimated 3D camera geometry and second images are classified using a constrained agglomerative hierarchical image clustering method to retrieve the images the users search. The constrained agglomerative hierarchical image clustering method provides balanced hierarchical layers, independent of the number of images within the cluster. It also provides a convenient way to browsing, navigating, and categorizing of the images with various viewpoints, illumination, and partial occlusion.

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Graf, Holger; Larson, Mats; Stork, André

Interactive 3D Subdomaining using Adaptive FEM based on Solutions to the Dual Problem

2014

Proceedings of the 2014 Virtual Reality International Conference : VRIC 2014. New York: ACM Press, 2014, 8 p.

Virtual Reality International Conference (VRIC) <16, 2014, Laval, France>

This paper presents a new technique for automatic, interactive 3D subdomaining coupled to mesh and simulation refinements in order to enhance local resolutions of CAE domains. Numerical simulations have become crucial during the product development process (PDP) for predicting different properties of new products as well as the simulation of various kinds of natural phenomena. "What-if-scenarios" and conceptual changes to either the boundary or the domain are time consuming and cost intensive. Most of the time, engineers are interested in a deeper understanding of local quantities rather than being exposed to an iterative re-simulation of the overall domain. New techniques for automatic and interactive processes are then challenged by the cardinality and structural complexity of the CAE domain. This paper introduces a new interactive technique that automatically reduces the analysis space, and allows engineers to enhance the resolution of local problems without a need for recalculating the global problem. The technique, integrated into a VR based front end, achieves faster reanalysis cycles compared with traditional COTS tool chains and engineering workflows.

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Aderhold, Andreas; Wilkosinska, Katarzyna; Corsini, Massimiliano; Jung, Yvonne; Graf, Holger; Kuijper, Arjan

The Common Implementation Framework as Service - Towards Novel Applications for Streamlined Presentation of 3D Content on the Web

2014

Marcus, Aaron (Ed.): Design, User Experience, and Usability. Proceedings Part II : User Experience Design for Diverse Interaction Platforms and Environments. DUXU 2014. Berlin, Heidelberg, New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8518), pp. 3-14

International Conference on Design, User Experience and Usability (DUXU) <3, 2014, Heraklion, Crete, Greece>

We solve a standing issue of the recently published Common Implementation Framework (CIF) for Online Virtual Museums: programmatic access to the transcoding, optimization and template rendering infrastructure of the CIF. We propose a method that enables researchers and developers to build novel systems on top of the CIF infrastructure beyond its current Cultural Heritage workflow. Therefore, we introduce a way to programmatically access the powerful backend of the CIF through a universal access layer, addressable by standards like HTTP and the JSON Data Interchange Format. In order to demonstrate our approach, we present two different use cases in which the CIF pipeline is utilized as a service through the proposed resource-based access layer: a native mobile iOS application for browsing 3D model repositories realizing just-in-time optimization of large models, and a MeshLab plugin to asynchronously convert and prepare a model for the Web.

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Olbrich, Manuel; Graf, Holger; Kahn, Svenja; Engelke, Timo; Keil, Jens; Rieß, Patrick; Webel, Sabine; Bockholt, Ulrich; Picinbono, Guillaume

Augmented Reality Supporting User-centric Building Information Management

2013

The Visual Computer, Vol.29 (2013), 10, pp. 1093-1105

The rapid development of geo-referenced information changed the way on how we access and interlink data. Smartphones as enabling devices for information access are main driving factor. Thus, the hash key to information is the actual position registered via camera and sensory of the mobile device. A rising technology in this context is Augmented Reality (AR) as its fuses the real world captured with the smartphone camera with geo-referenced data. The technological building blocks analyse the intrinsic sensor data (camera, GPS, inertial) to derive a detailed pose of the smartphone aiming to align geo-referenced information to our real environment. In particular, this is interesting to applications where 3D models are used in planning and organization processes as, e.g., facility management. Here, Building Information Models (BIM) were established in order to hold "as built" information, but also to manage the vast amount of additional information coming with the design, such as building components, properties, maintenance logs, documentation, etc. One challenge is to enable stakeholders involved in the overall building lifecycle to get mobile access to the management system within onsite inspections and to automatise feedback of newly generated information into the BIM. This paper describes a new AR framework that offers on-site access to BIM information and user centric annotation mechanism.

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Baldassari, Guido Lucci; Demetrescu, Emanuel; Pescarin, Sofia; Eriksson, Joakim; Graf, Holger

Behind Livia's Villa: A Case Study for the Devolution of Large Scale Interactive "in-site" to "on-line" Application

2013

Marcus, Aaron (Ed.): Design, User Experience, and Usability: Part IV : Web, Mobile, and Product Design. Berlin, Heidelberg, New York: Springer, 2013. (Lecture Notes in Computer Science (LNCS) 8015), pp. 238-247

International Conference on Design, User Experience and Usability (DUXU) <2, 2013, Las Vegas, NV, USA>

This work presents a methodology for designing online web presentations reusing a large scale, interactive and immersive VR installation by mapping assets as well as interactions to a low capability environment. With the emergence of WebGL plugin-free interactive 3D graphics inside limited information processing environments, e.g. browser technologies, becomes reality. However, macro VR worlds typically use large or even out-of-core data sets in order to produce and communicate scientifically relevant content. The major challenge still remains on how we can redesign and optimize applications that have been planned for macro VR worlds and map those to adequate concepts of micro scale worlds. We showcase this in the area of virtual archaeology for the online virtual museum of "Villa Di Livia", part of the bigger project "Flaminia Reloaded", in which several limitations could become crucial. The elaborated workflow could easily be adopted by other VMs and assist in future migrations.

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Jung, Yvonne; Behr, Johannes; Graf, Holger

Creating Interactive 3D Web Apps Using X3DOM

2013

2013 Digital Heritage International Congress. Volume 2 : DigitalHeritage. New York: The Institute of Electrical and Electronics Engineers (IEEE), 2013, p. 763

Digital Heritage International Congress (DigitalHeritage) <2013, Marseille, France>

In recent years a new trend for interactive 3D graphics from large scale macro VR worlds to micro scale 3D interactive visual environments that can be deployed on any platform and device became visible. One of the pushing factors is the availability of modern smartphones and tablets that provide miniaturized platforms and dedicated enabling technologies for the rendering of and interaction with 3D content. WebGL as a JavaScript binding for OpenGL ES drove significantly the developments of 3D applications for the Web, and enabled traditional Web Browsers to render interactive 3D content implementing an extension to its DOM. Using JavaScript and CSS, thus, it is then possible to customize rendering and interaction through HTML5 technologies. As it is deployable also in Browser instances for smartphones, 3D interactive visual environments become available on mobile devices. One of the challenges here is to embed low-level WebGL calls into a higher level of abstraction that at the same time allows for a declarative description of the 3D scene to be rendered. X3DOM is one environment that at the same time enables the development as well as the deployment of interactive 3D declarative content for the Web. This tutorial is intended to be a quick start for people who have no experience with 3D graphics so far but want to try out X3DOM. Authoring X3DOM content is very similar to authoring HTML. The tutorial introduces declarative 3D in HTML5, how to integrate 3D elements into the DOM, adding dynamics using adequate scripting through JavaScript and styling via CSS. It is intended for non-experts or newbies to 3D graphics and web design professionals alike.

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Gockel, Bianca; Graf, Holger (Betreuer)

Evaluating Selected UX Aspects within Interactive Virtual Museum Installations

2013

Fulda, Hochschule, Bachelor Thesis, 2013

Nowadays, virtual museums are not sufficiently adapted to the users' interests and needs, as requirements analysis before the implementation as well as evaluations during the development work are hardly realised in the digital cultural heritage domain. Within the scope of this work, an evaluation of virtual museums was conducted in order to investigate selected User Experience (UX) aspects. Four UX aspects were specifically chosen to be elevated and analysed. Latest research in HCI shows that both instrumental and non-instrumental product qualities influence the users' perceptions of an interactive product. Therefore, the work focuses on the three instrumental aspects utility, learnability and efficiency as well as the non-instrumental aspect stimulation. An evaluation was designed for these aspects based on a written survey using a questionnaire to obtain quantitative data. It was complemented by an interview guiding through the use of demonstrators, in order to also collect qualitative data. To obtain concrete results the evaluation was applied to virtual museums which were presented at the Archeovirtual 2012 by involving the visitors. Received results of five virtual museums, each one from a different technological domain, are discussed in this work. On the basis of a subsequent assessment the level of maturity of each addressed virtual museum should be determined. Furthermore, strengths and weaknesses were identified with the aim to provide developers suggestions for an improved user experience on selected aspects in subsequent development iterations.

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Wilkosinska, Katarzyna; Aderhold, Andreas; Graf, Holger; Jung, Yvonne

Towards a Common Implementation Framework for Online Virtual Museums

2013

Marcus, Aaron (Ed.): Design, User Experience, and Usability. Proceedings Part II : Health, Learning, Playing, Cultural, and Cross-Cultural User Experience. Berlin, Heidelberg, New York: Springer, 2013. (Lecture Notes in Computer Science (LNCS) 8013), pp. 321-330

International Conference on Design, User Experience and Usability (DUXU) <2, 2013, Las Vegas, NV, USA>

We present a prototypical solution to a common problem in the Cultural Heritage (CH) domain. After creation, 3D models of CH artifacts need to be processed to a format suitable for presentation on multiple platforms, e.g. in a Web Browser for online virtual museum applications, to target desktop computers and mobile devices alike. The constraints of an in-browser presentation give rise to a series of optimization and conversion concerns that need to be addressed to successfully display the CH objects in a Web application. Current 3D authoring tools do not readily support this kind of optimization and conversion required for CH domain scenarios. We therefore propose a web-based service framework, which solves the problem of pipelining 3D models for interactive Web presentations. We apply open-source technologies like X3DOM, Flask, Celery, and Redis to create a Common Implementation Framework (CIF) that allows content designers or researchers to optimize their 3D models for the Web through a simple one-step process.

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Graf, Holger; Stork, André

Virtual Reality Based Interactive Conceptual Simulations: Combining Post-processing and Linear Static Simulations

2013

Shumaker, Randall (Ed.): Virtual Augmented and Mixed Reality. Designing and Developing Augmented and Virtual Environments. Proceedings Part I : VAMR 2013. Berlin, Heidelberg, New York: Springer, 2013. (Lecture Notes in Computer Science (LNCS) 8021), pp. 13-22

International Conference Virtual Augmented and Mixed Reality (VAMR) <5, 2013, Las Vegas, NV, USA>

This paper presents a new approach for the design and realization of a Virtual Reality (VR) based engineering front end that enables engineers to combine post processing tasks and finite element methods for linear static analyses at interactive rates. "What-if-scenarios" have become a widespread methodology in the CAE domain. Here, designers and engineers interact with the virtual mock-up, change boundary conditions (BC), variate geometry or BCs and simulate and analyze its impact on the CAE mock-up. The potential of VR for post-processing engineering data enlightened ideas to deploy it for interactive investigations at conceptual stage. While it is a valid hypothesis, still many challenges and problems remain due to the nature of the "change'n play" paradigm imposed by conceptual simulations as well as the non-availability of accurate, interactive FEM procedures. Interactive conceptual simulations (ICS) require new FEM approaches in order to expose the benefit of VR based front ends.

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Gockel, Bianca; Graf, Holger; Pagano, Alfonsina; Pescarin, Sofia; Eriksson, Joakim

VMUXE. An Approach to User Experience Evaluation for Virtual Museums

2013

Marcus, Aaron (Ed.): Design, User Experience, and Usability: Part I : Design Philosophy, Methods, and Tools. Berlin, Heidelberg, New York: Springer, 2013. (Lecture Notes in Computer Science (LNCS) 8012), pp. 262-272

International Conference on Design, User Experience and Usability (DUXU) <2, 2013, Las Vegas, NV, USA>

This paper presents a new approach for the evaluation of User Experience (UX) aspects applied to virtual museums (VM) - VMUXE. A wide percentage of projects and applications for VMs are often "born and buried" in digital labs, without having been experimented and monitored with people. These "prototypes" are the result of experts, technicians, curators, combined together to give birth for multidisciplinary and avant-garde outputs. Earlier attempts to evaluate VM installations failed due to the lack of strategy facing the multidimensional complexity in studying and comparing digital applications in different installations using different devices and metaphors offering different UXs. As a conclusion "communicating" culture through the aid of advanced technology was not a technological issue, but an epistemological one. Setting up a good process of evaluation and analysis is therefore important for establishing next generation virtual museums (NGVM) aiming to reach certain goals such as knowledge exchange, cognitive improvement and heritage communication.

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Kahn, Svenja; Olbrich, Manuel; Engelke, Timo; Keil, Jens; Rieß, Patrick; Webel, Sabine; Graf, Holger; Bockholt, Ulrich; Picinbono, Guillaume

Beyond 3D "as-Built" Information using Mobile AR Enhancing the Building Lifecycle Management

2012

Kuijper, Arjan (Ed.) et al.: 2012 International Conference on Cyberworlds. Proceedings : Cyberworlds 2012. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2012, pp. 29-36

International Conference on Cyberworlds (CW) <11, 2012, Darmstadt, Germany>

The success of smartphone technologies changed the way information is processed as more and more geo-referenced structures are emerging linking information to specific locations within our environment. Thereby, Augmented Reality has become a key technology as it analyses the smartphone sensor data (camera, GPS, inertial) to derive the detailed pose of the smartphone, with the aim to correlate our real environment to the geo-referenced information space. In particular, this is relevant for application fields where 3Dmodels are used in planning and organization processes as e.g. facility management. In facility construction and management Building Information Model (BIM) was established as a standard that not only holds the 3D-building-geometry but encompasses pipe/electrical systems as well as semantic building information, for example properties and conditions of building components. With this motivation our work integrates BIM and Augmented Reality.

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Wißner, André-Michael; Graf, Holger (Betreuer)

Konzeption, Implementierung und Evaluation eines Algorithmus zur Bestimmung der Gelenkrotationen Anhand von Kinect-Daten

2012

Campus Friedberg, TH Mittelhessen, Bachelor Thesis, 2012

Die Bachelorarbeit umfasst die Konzipierung, Entwicklung und Implementierung von Algorithmen zur Bestimmung von Gelenkrotationen. Hierbei werden zwei Algorithmen gezeigt, die verschiedene mathematische Vorgehensweisen zum Schätzen der Gelenkwinkel verwenden. Diese beiden Varianten können dann beispielsweise in das Forschungsprojekt Motivotion60+ des Institut für grafische Datenverarbeitung Fraunhofer integriert werden. Dieses Projekt befasst sich mit dem spielerischen Fithalten von Menschen ab 60 Jahren. Durch verschiedene Körperposen und Bewegungen ist es in diesem Projekt möglich, Spiele zu steuern. Dabei ist es wichtig, die einzelnen Posen zu kontrollieren und mit vorgegebenen Posen zu vergleichen. An diesem Punkt werden Regeln definiert, die mit einem der beiden Algorithmen arbeiten. Bei der Erkennung der Posen werden die einzelnen Rotationswinkel errechnet und diese für die Regeln und den Vergleich der gemachten Posen verwendet. In dieser Bachelorarbeit wird zudem ein Editor entwickelt, der dem Benutzer die Möglichkeit geben soll, selbst Regeln für solche Anwendungen wie etwa Motivotion60+ zu erstellen. Dabei befasst sich die Bachelorarbeit mit aktuellen Kamerasystemen und verschiedenen Möglichkeiten zum Erfassen von Körperbewegungen. Die bekanntesten Techniken zum Erfassen von Personen und damit die Körperbewegungen sind die markerbasierten und die markerlosen Erfassungssysteme. Diese Techniken werden bei aktuellen Kinofilmen verwendet. Man spricht bei dieser Technik auch von Motion Capturing. [MM00] Je nach dem welches Erfassungssystem man wählt, ist es zwingend erforderlich, ein passendes Kamerasystem zu wählen. Bei der Entwicklung der beiden Algorithmen wurde das Kamerasystem Kinect von Microsoft gewählt.

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Graf, Holger

A "Change'n Play" Software Architecture Integrating CAD, CAE and Immersive Real-Time Environments

2011

Martin, Ralph (Ed.) et al.: The 12th International Conference on Computer-Aided Design and Computer Graphics. Proceedings : CAD / Graphics 2011. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2011, pp. 3-10

International Conference on Computer-Aided Design and Computer Graphics <12, 2011, Jinan, China>

This paper presents a "change'n play" software architecture in order to realize user-centric aspects for, integrated engineering analysis tasks within immersive environments. The proposed architecture has been designed to enable conceptual simulations performed on an engineering mock-up. Major attention is given to the realization of modules and functionalities going far beyond traditional post-processing capabilities, establishing a user centric problem solving environment. It allows closed turnaround simulation-to-visualization loops as well as an inclusion of traditional point-and-click legacy systems, steered from an immersive environment and providing interchangeable mechanism. Existing research work addresses only different aspects, even worse neither does provide a holistic approach nor does show on how to actually do it. Aim of this paper is therefore, to propose and develop an architectural blueprint, supporting "what-if" reasoning with respect to preliminary design analysis objectives: Executed within one single point of access and based on a distributed, hybrid 2D legacy system/VR interactive environment.

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Graf, Holger; Hazke, Leon; Kahn, Svenja; Malerczyk, Cornelius

Accelerated Real-Time Reconstruction of 3D Deformable Objects from Multi-view Video Channels

2011

Duffy, Vincent G. (Ed.): Digital Human Modeling : Third International Conference: ICDHM 2011. Berlin, Heidelberg, New York: Springer, 2011. (Lecture Notes in Computer Science (LNCS) 6777), pp. 282-291

International Conference on Digital Human Modeling (ICDHM) <3, 2011, Orlando, FL, USA>

In this paper we present a new framework for an accelerated 3D reconstruction of deformable objects within a multi-view setup. It is based on a new memory management and an enhanced algorithm pipeline of the well known Image-Based Visual Hull (IBVH) algorithm that enables efficient and fast reconstruction results and opens up new perspectives for the scalability of time consuming computations within larger camera environments. As a result, a significant increase of frame rates for the volumetric reconstruction of deformable objects can be achieved using an optimized CUDA-based implementation on NVIDIA's Fermi-GPUs.

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Kahn, Svenja; Malerczyk, Cornelius; Graf, Holger; Bockholt, Ulrich

Capturing Motion Skills with Silhouette-Based Numerical Pose Estimation

2011

BIO Web of Conferences, Vol.1 (2011), 4 p.

The International Conference SKILLS <1, 2011, Montpellier, France>

The capturing of human movements is an important step for the analysis of human skills, e.g. for sports analysis or for learning-by-demonstration tasks. In this paper we introduce a new markerless pose estimation method which estimates human poses from silhouettes. The presented numerical pose estimation algorithm adapts a non-deterministical annealing schedule for silhouette based motion capturing. The pose is estimated by numerically minimizing the differences between the silhouettes of synthesized views of a 3D avatar and the silhouettes of the real person in the camera images. The evaluation results of simulation experiments quantify the trade-off between the accuracy and the execution time of the presented algorithm.

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Graf, Holger; Soubra, Souheil; Picinbono, Guillaume; Keough, Ian; Tessier, Alex; Khan, Azam

Lifecycle Building Card: Toward Paperless and Visual Lifecycle Management Tools

2011

Attar, Ramtin (Ed.): 2011 Proceedings of the Symposium on Simulation for Architecture and Urban Design : SimAUD, pp. 135-142

Symposium on Simulation for Architecture and Urban Design (SimAUD) <2, 2011, Boston, MA, USA>

This paper presents a novel vision of paperless and visual lifecycle building management tools based on the coupling between Building Information Models (BIM) and Augmented Reality (AR) called Lifecycle Building Card. As the use of BIM increases within the architecture, engineering, and construction industries, new opportunities emerge to help stakeholders and maintenance operators to leverage the BIM dataset for lifecycle issues using realtime environments and simulation. In particular, a tighter coupling of BIM with computer vision techniques could enable innovative lifecycle management tools based on AR concepts. In this context, this work explores the possibilities and derives theoretical and practical concepts for the use of BIM enhanced by AR for supporting maintenance activities in buildings. An implementation of a wireless spatially-aware display is presented as a first step toward the stated vision.

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Graf, Holger; Stork, André

Linear Static, Real-Time Finite Element Computations based on Element Masks

2011

The American Society of Mechanical Engineers (ASME): ASME 2011 World Conference on Innovative Virtual Reality : WINVR 2011. New York: The American Society of Mechanical Engineers, 2011, 9 p.

ASME World Conference on Innovative Virtual Reality (WINVR) <3, 2011, Milan, Italy>

This paper presents a new method for the manipulation of a given CAE domain in view of VR based explorations that enables engineers to interactively inspect and analyze a linear static domain. The interactions can ideally be performed in real-time in order to provide an intuitive impression of the changes to the underlying volumetric domain. We take the approach of element masking, i.e. the blending out of computations resulting from computational overhead for inner nodes, based on the inversion of the stiffness matrix. This allows us to optimize the re-simulation loop and to achieve real-time performance for strain and stress distributions with immediate visualization feedback caused by interactively changing boundary conditions. The novelty of the presented approach is a direct coupling of view dependent simulations and its close linkage to post-processing tasks. This allows engineers to also inspect the changes of the stress field inside of the volume during, e.g. cross sectioning.

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Jung, Yvonne; Graf, Holger; Behr, Johannes; Kuijper, Arjan

Mesh Deformations in X3D via CUDA with Freeform Deformation Lattices

2011

Shumaker, Randall (Ed.): Virtual and Mixed Reality - Systems and Applications: Part II : International Conference, Virtual and Mixed Reality 2011. Berlin, Heidelberg, New York: Springer, 2011. (Lecture Notes in Computer Science (LNCS) 6774), pp. 343-351

International Conference on Virtual and Mixed Reality (VMR) <4, 2011, Orlando, FL, USA>

In this paper we present a GPU-accelerated implementation of the well-known freeform deformation algorithm to allow for deformable objects within fully interactive virtual environments. We furthermore outline how our real-time deformation approach can be integrated into the X3D standard for more accessibility of the proposed methods. The presented technique can be used to deform complex detailed geometries without pre-processing the mesh by simply generating a lattice around the model. The local deformation is then computed for this lattice instead of the complex geometry, which efficiently can be carried out on the GPU using CUDA.

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Koch, Markus; Graf, Holger (Betreuer)

Multi-Kamera Netzwerk für markerloses Motion Capturing

2011

Wiesbaden, Hochschule RheinMain, Master Thesis, 2011

Diese Masterarbeit beschäftigt sich mit der Frage, inwieweit sich eine Kameraakquisition für markerloses Motion Capturing in einem Netzwerk mehrerer Rechner verteilen lässt, ohne den eigentliche Prozess der Rekonstruktion zu beeinträchtigen. Hierfür werden vorhandene Algorithmen untersucht und auf eine Client-Server-Architektur verteilt, um so eine ideale Lastverteilung der einzelnen Prozesse zwischen den beteiligten Rechnern zu erzielen. Abschließend wird die Geschwindigkeit der Implementierung untersucht und auf verschiedenen Systemen getestet. Die Schwierigkeit bei einem verteilten System ist einerseits die Synchronisierung aller Komponenten und andererseits die Diskrepanz aus auftretender Datenmenge und im Netzwerk verfügbarer Bandbreite. Zur Synchronisierung wurden Routinen implementiert, die ausschließlich vom Server angestoßen werden können und eine Bestätigung von den Clients erwartet. Dadurch werden sämtliche Clients auf die Geschwindigkeit der schwächsten Komponente gezwungen. Die ebenfalls vom Server ausgehende Triggerung aller Kameras ermöglicht ein synchrones Auslösen. Anhand einer Analyse der auftretenden Bildinformationen wurde zur Datenratenreduktion eine Lauflängenkodierung implementiert, die sowohl einfach umzusetzen als auch schnell in ihrer Berechnung ist. Daraus resultiert eine Trennung der einzelnen Bestandteile mit der Umsetzung von Bayerfilter, Silhouetten-Extraktion, Texturierung und Kodierung auf Seiten der Clients und Dekodierung, Bayerfilter der Texturen und Berechnung der visuellen Hülle auf dem Server. Sämtliche Leistungsanpassungen wurden auf selbst im Konsumentenbereich einfachster Hardware durchgeführt und an die verfügbaren Rechner angepasst. Die Funktionsfähigkeit dieser Umsetzung wurde mit vier Kameras an zwei Clients und acht Kameras an vier Clients getestet und erreichte hierbei eine Geschwindigkeit von durchschnittlich 18 Bildern pro Sekunde.

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Graf, Holger; Tamanini, Christian; Geißler, Lukas

Muntermacher - "Think and Move" Interface and Interaction Design of a Motion-Based Serious Game for the Generation Plus

2011

Stephanidis, Constantine (Ed.): Universal Access in Human-Computer Interaction: Part II : Users Diversity. Berlin, Heidelberg, New York: Springer, 2011. (Lecture Notes in Computer Science (LNCS) 6766), pp. 149-158

International Conference on Universal Access in Human-Computer Interaction (UAHCI) <6, 2011, Orlando, FL, USA>

This paper presents a holistic approach to design a media system based on a new user interface and interaction device aimed to motivate seniors of the generation plus enhancing their daily physical activity. As a result of the newly designed game, the senior finds himself within a colorful world of a game in which he interacts with small lively figures using a newly designed interaction device accounting for physical activity. The combination of both design elements, lead to a gameplay that provides adequate mechanism for cognitive and physical activity, challenging representatives of the generation plus to exercise more.

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Jung, Yvonne; Behr, Johannes; Graf, Holger

X3DOM as Carrier of the Virtual Heritage

2011

Remondino, Fabio (Ed.) et al.: Proceedings of the 4th ISPRS International Workshop 3D-ARCH 2011 : 3D Virtual Reconstruction and Visualization of Complex Architectures [CD-ROM]. (The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XXXVIII-5/W16), 8 p.

ISPRS International Workshop 3D-ARCH <4, 2011, Trento, Italy>

Virtual Museums (VM) are a new model of communication that aims at creating a personalized, immersive, and interactive way to enhance our understanding of the world around us. The term "VM" is a short-cut that comprehends various types of digital creations. One of the carriers for the communication of the virtual heritage at future internet level as de-facto standard is browser front-ends presenting the content and assets of museums. A major driving technology for the documentation and presentation of heritage driven media is real-time 3D content, thus imposing new strategies for a web inclusion. 3D content must become a first class web media that can be created, modified, and shared in the same way as text, images, audio and video are handled on the web right now. A new integration model based on a DOM integration into the web browsers? architecture opens up new possibilities for declarative 3D content on the web and paves the way for new application scenarios for the virtual heritage at future internet level. With special regards to the X3DOM project as enabling technology for declarative 3D in HTML, this paper describes application scenarios and analyses its technological requirements for an efficient presentation and manipulation of virtual heritage assets on the web.

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Graf, Holger; Santos, Pedro; Stork, André

Augmented Reality Framework Supporting Conceptual Urban Planning and Enhancing the Awareness for Environmental Impact

2010

Khan, Azam (Ed.): 2010 Proceedings of the Symposium on Simulation for Architecture and Urban Design, pp. 119-128

Symposium on Simulation for Architecture and Urban Design (SimAUD) <1, 2010, Orlando, FL, USA>

This paper introduces a new augmented reality framework based on a multi-source urban planning backbone aiming at interactively investigating fast "what-if" analysis of urban planning simulations and creating awareness of possible environmental impact. The process of advanced urban planning nowadays includes the simulation of physical phenomena, its analysis, visualization and interpretation in order to evaluate the impact on the layout of the planning. For example, noise and air pollution, annoyances due to both nearby transportation infrastructure and urban traffic have become a serious concern for citizens. In order to provide major aid to the involved stakeholders, especially city managers, new techniques for the preparation, representation and interpretation of the typically large amount of resulting simulation data are required. These must be designed in order to enhance the perceptual and cognitive processes of users to facilitate faster interpretation and decision making. Hence, we introduce a new augmented reality framework which not only allows users to visualize but also to analyze physical phenomena in fast "what-if"- scenarios. By changing boundary conditions, parameters and re-simulating at interactive rates results can be augmented into real world planning layouts. Augmenting reality, urban planning and layouts with resulting simulation data through real-time visualizing tools provides a new and efficient interactive post processing unit for the exploration and analysis of the environmental impact due to changing conditions.

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Geißler, Lukas; Tamanini, Christian; Graf, Holger (Betreuer)

Muntermacher. Denken und Bewegen: Interface Design of a Motion-Based Serious Game for the Generation Plus

2010

Darmstadt, Hochschule, Diplomarbeit, 2010

"Muntermacher" ist ein Videospiel für Senioren, welches unter Berücksichtigung der Kriterien altersgerechter Mediengestaltung konzipiert und prototypisch realisiert wurde. Ziel des Spiels ist es, ältere Menschen auf spielerische Weise zu mehr sportlicher Aktivität zu motivieren. Langfristig soll hierdurch ein möglichst langes und selbstständiges Leben ermöglicht werden. Um dieses Ziel zu erreichen, setzt das Konzept auf eines der wichtigsten Bedürfnisse älterer Menschen: den Erhalt geistiger Fähigkeiten. Im Gegensatz zur sportlichen Motivation ist der Anreiz sich durch "Gehirnjogging" geistig fit zu halten innerhalb der Zielgruppe stark ausgeprägt. Studien belegen jedoch, dass die allgemeine Leistungsfähigkeit durch Gehirnjogging nicht gesteigert werden kann, die Kombination mit körperlicher Aktivität jedoch sehr wirksam ist. Hier setzt "Muntermacher" an, indem es beide Bereiche miteinander verbindet. Das Spiel lässt den Nutzer in humorvoller Art und Weise verschiedene Denksport- Bereiche trainieren. Der Spieler interagiert dabei mit einem neuartigen Eingabegerät, welches im Wesentlichen aus einem modifizierten Gymnastikband und zwei Kraftbällen besteht. "Muntermacher" nutzt den Wunsch des Erhalts geistiger Fähigkeiten im Alter als motivierenden Faktor und verbessert auf effektive Weise die körperliche Fitness der Senioren.

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Graf, Holger; Yoon, Sang Min; Malerczyk, Cornelius

Real-Time 3D Reconstruction and Pose Estimation for Human Motion Analysis

2010

IEEE Signal Processing Society (SPS): IEEE International Conference on Image Processing. Proceedings : IEEE International Conference on Image Processing. New York: The Institute of Electrical and Electronics Engineers (IEEE), 2010, pp. 3981-3984

International Conference on Image Processing (ICIP) <17, 2010, Hong Kong>

In this paper, we present a markerless 3D motion capture system based on a volume reconstruction technique of non rigid bodies. It depicts a new approach for pose estimation in order to fit an articulated body model into the captured real-time information. We aim at analyzing athlete's movements in real-time within a 3D interactive graphics system. The paper addresses recent trends in vision based analysis and its fusion with 3D interactive computer graphics. Hence, the proposed system presents new methods for the 3D reconstruction of human body parts from calibrated multiple cameras based on voxel carving techniques and a 3D pose estimation methodology using Pseudo-Zernike Moments applied to an articulated human body model. Several algorithms have been designed for the deployment within a GPGPU environment allowing us to calculate several principle process steps from segmentation and reconstruction to volume optimization in real-time.

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Becker, Sebastian; Graf, Holger (Betreuer)

Sensorische Rekonstruktion von 3D-Bewegungsabläufen anhand von 2D-Bildinformation

2010

Darmstadt, Hochschule, Bachelor Thesis, 2010

3D-Objekt Visualisierung sowie Rekonstruktion und Verfolgung von Bewegungsabläufen in Echt-Zeit ist eine enorme Herausforderung gegenwärtiger Bestrebungen im Fusionsbereich der Computer Vision und Computer Grafik. Zielstellung der Aktivitäten ist es, Nutzern und Wissenschaftlern einen intuitiveren und realistischeren Erfahrungswert über das Objektverhalten zu vermitteln. Basierend auf Methoden der Computer Vision wird versucht aus 2D-Bilddaten auf die 3D-Strukturen und Bewegungen von realen Objekten zu schließen. Die hier vorgestellte Arbeit befasst sich mit der Problemstellung ein artikuliertes, biokinematisches Menschmodell in einen von mehreren Kameras erfassten Bewegungsablauf eines Menschen einzupassen. Zugrundeliegende Bildsegmentierungsverfahren erlauben dabei eine Extraktion der menschlichen Silhouetten, in welche das digitale Modell entsprechend eingepasst und optimiert werden können. Die vorliegende Arbeit untersucht mathematische Möglichkeiten und resultierende Fragestellungen, das Menschmodell in die Silhouette ohne die Hilfe einer Datenbank einzupassen. Jeweils ein Modell soll an die Silhouetten einer Momentaufnahme der Kameras angepasst werden. Diese Anpassung erfolgt durch die Hilfe der Kamerakalibrierungsdaten und eines Optimierungsalgorithmus. Nachdem die optimalen Posen des Menschmodells zur jeweiligen Silhouette gefunden wurden, werden diese Posen verglichen, um daraus eine Modell-Pose zu approximieren, die alle Silhouetten der verschiedenen Momentaufnahmen gut nachempfindet.

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Yoon, Sang Min; Malerczyk, Cornelius; Graf, Holger

3D Skeleton Extraction from Volume Data Based on Normalized Gradient Vector Flow

2009

Chen, Min (Ed.) et al.: WSCG 2009. Full Papers Proceedings. Plzen: University of West Bohemia, 2009, pp. 177-182

International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG) <17, 2009, Plzen, Czech Republic>

Skeleton extraction and visualization of 3D reconstructed target objects from multiple views continues to be a major challenge in terms of providing intuitive and uncluttered images that allow the users to understand their data. This paper presents a three-dimensional skeleton extraction technique of deformable objects based on a normalized gradient vector flow in order to analyze and visualize its characteristics. 3D deformable objects are reconstructed by an image based visual hull technique from known extrinsic and intrinsic camera parameters and silhouettes which are extracted from each camera. Our 3D skeleton extraction methodology employs the normalized gradient vector flow which is a vector diffusion approach based on partial differential equations. The euclidean distance of the magnitude of a normalized gradient vector flow is used to extract the medial axis of volume data. A markerless 3D skeletonization of reconstructed objects from multiple images might be applied to retrieve the 3D model or correct the 3D motion of the target objects.

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Yoon, Sang Min; Graf, Holger

Automatic Skeleton Extraction and Splitting of Target Objects

2009

IEEE Signal Processing Society (SPS): 2009 IEEE International Conference on Image Processing. Proceedings : ICIP 2009. Los Alamitos, Calif.: IEEE Computer Society, 2009, pp. 2421-2424

International Conference on Image Processing (ICIP) <16, 2009, Cairo, Egypt>

The understanding of object's kinematic structure is one of main challenges in the area of computer vision. Especially, skeleton of deformable objects, which is familiar with human visual perception, visualizes its characteristic using few data. This paper describes an efficient approach for automatic skeleton extraction and its splitting in the space of diffusion tensor fields, which are generated from normalized gradient vector flow fields of a given image. Our method is based on two steps: Skeleton extraction using second order diffusion tensor fields, Splitting skeleton using dissimilarity measure between neighbor elements. The evaluation proofs the efficiency of our technique which might be applied to object retrieval, pose estimation and action recognition, object registration and visualization.

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Yoon, Sang Min; Graf, Holger

Automatic Trimap Extraction for Efficient Alpha Matting Based on Gradient Field Transforms

2009

Institute for Systems and Technologies of Information, Control and Communication (INSTICC): VISIGRAPP 2009. Proceedings : International Joint Conference on Computer Vision and Computer Graphics Theory and Applications [CD-ROM]. INSTICC Press, 2009, GRAPP, pp. 52-57

International Conference on Computer Graphics Theory and Applications (GRAPP) <4, 2009, Lisboa, Portugal>

Image/Video Matting aims at solving the problem of accurate foreground estimation from a given background within still images or video sequences. The standard alpha matting method starts from a trimap, which separates an input image into three regions: definitely foreground, definitely background, and unknown regions. This paper presents an automatic trimap extraction based on an affine transformation of gradient fields in order to achieve an improved and robust Image/Video matting method. A gradient field based background and foreground segmentation technique provides a trimap extraction, which is robust to changing light conditions within semi-transparent objects. Our proposed background subtraction is based on affine transformed gradient projections of the input and background image and removes the background texture from a given image, preserving the texture of the foreground objects. The presented automatic trimap extraction method reduces the manual labor work in extracting and embedding target objects into a new background image or video sequences and might find its application within the broadcasting or movie industry.

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Graf, Holger

Enabling VR Based Conceptual Simulations for Engineering Tasks

2009

International Association for Development of the Information Society (IADIS): IADIS Multi Conference on Computer Science and Information Systems 2009 : MCCSIS 2009. IADIS Press, 2009, pp. 81-88

IADIS Multi Conference on Computer Science and Information Systems (MCCSIS) <2009, Algarve, Portugal>

In this work new methodologies for interactive 3D (volume) mesh manipulations integrating the overall process chain of linear static analysis are presented. It intends to proof the introduced concepts and to pave the way for conceptual simulations within virtual environments for the engineering domain. The methodologies try to close the 'user in the loop' paradigm for fast 'what-if-analysis' in view of geometrical changes of the given analysis domain within a highly interactive 3D visual environment. The paper is based on previous work of the author and presents an approach of combining real-time computations for topological operations caused by a quality measure on simplicial elements, remeshing of 3D triangular/tetrahedral unstructured meshes during a geometrical and a newly introduced submodelling procedure for complex 3D analysis. The methodologies for mesh manipulations combined with a submodelling procedure allows for local problem solving of a complex global analysis domain enabling fast preliminary local design changes and their impact to local stress fields. The work is motivated as current virtual reality systems are facing a paradigm shift away from pure visualisation and design review systems to more generative environments.

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Yoon, Sang Min; Graf, Holger

Hierarchical Online Image Representation Based on 3D Camera Geometry

2009

Institute for Systems and Technologies of Information, Control and Communication (INSTICC): VISIGRAPP 2009. Proceedings : International Joint Conference on Computer Vision and Computer Graphics Theory and Applications [CD-ROM]. INSTICC Press, 2009, VISAPP, pp. 54-59

International Conference on Computer Vision Theory and Applications (VISAPP) <4, 2009, Lisboa, Portugal>

Within this paper, we present a hierarchical online image representation method with 3D camera position to efficiently summarize and classify the images on the web. The framework of our proposed hierarchical online image representation methodology is composed of multiple layers: at the lowest layer in the hierarchical structure, relationship between multiple images is represented by their recovered 3D camera parameters by automatic feature detection and matching. At the upper layers, images are classified using constrained agglomerative hierarchical image clustering techniques, in which the feature space established at the lowest layer consists of the camera's 3D position. Constrained agglomerative hierarchical online image clustering method is efficient to balance the hierarchical layers whether images in the cluster are many or not. Our proposed hierarchical online image representation method can be used to classify online images within large image repositories by their camera view position and orientation. It provides a convenient way to image browsing, navigating and categorizing of the online images that have various view points, illumination, and partial occlusion.

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Yoon, Sang Min; Malerczyk, Cornelius; Graf, Holger

Skill Measurement Through Real-Time 3D Reconstruction and 3D Pose Estimation

2009

Gutiérrez, Teresa (Ed.) et al.: SKILLS 09 : Enaction on SKILLS. Donostia - San Sebastián: SKILLS Consortium, 2009, pp. 59-65

International Conference on Multimodal Interfaces for Skills Transfer (SKILLS) <1, 2009, Bilbao, Spain>

Skill measurement for sports analysis is still a challenging issue for sports scientists. In recent years, video based analysis of body movements and its corrections has become a widespread tool within modern athlete training centres throughout the different training stages of the athletes' pre-competition preparation. The challenges imposed by this supporting service are manifold and range from high resolution capturing of the athlete to a precise real-time reconstruction of body movements. By augmenting ideal virtual poses to the real motions, a coach is able to analyze and communicate incorrect or even incomplete motions of the athlete. For the precise measurement of body motions, typically motion capture systems (MoCap) are used. During the last decade marker based motion capture systems matured and did find their way into the area of medical and sports science. Markerless motion capturing systems, however, are still in its infancy. This paper describes a new approach to markerless motion capturing and its use for sports skills measurement and analysis.

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Bockholt, Ulrich; Webel, Sabine; Engelke, Timo; Graf, Holger; Behr, Johannes

Virtual and Augmented Reality Training Platforms for Transfer of Skills

2009

Gutiérrez, Teresa (Ed.) et al.: SKILLS 09 : Enaction on SKILLS. Donostia - San Sebastián: SKILLS Consortium, 2009, pp. 39-45

International Conference on Multimodal Interfaces for Skills Transfer (SKILLS) <1, 2009, Bilbao, Spain>

Within the European project SKILLS Virtual and Augmented Reality platforms have been developed that are used for the realization of different training simulators in the field of sports (training of rowing and juggling), surgery (training of maxillofacial and telerobotic surgery), rehabilitation (rehabilitation of upper limp), maintenance (training of assembly procedures) and robotics (training of robot programming). These platforms are integrating capturing and rendering technologies. The capturing technologies are used to register specific criteria of skills to be hold in a digital representation. Thus, parameters relevant for specific skills are qualified and used as evaluation factors within the training simulators. The training simulators not only can simulate the virtual environment of the training situation, but this environment can be enhanced via multimodal renderings, fostering the training process and accelerating the training effect. The integrative platforms from scalable and adaptable frameworks that can be used to realize different training protocols and that can be adapted to the trainee's degree of skill. Therefore the training protocol can be specified via standardized application scripts.

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Yoon, Sang Min; Graf, Holger

3D Eye Position Based Interaction within Hierarchically Represented Images

2008

Güdükbay, Ugur (Ed.) et al.: 2008 3DTV-Conference: The True Vision - Capture, Transmission and Display of 3D Video [CD-ROM]. New York: IEEE Press, 2008, pp. 389-392

International Conference on 3DTV (3DTV-CON) <2, 2008, Istanbul, Turkey>

Our hierarchical image representation method is composed of multiple layers. On the lowest level, we will recover the 3D extrinsic camera parameter of images which will build the foundation of our system. Upper layers of our structure are separated with clustering algorithm, in which the feature space established within the lowest layer consists of the camera's 3D position and orientation. In this section, we will explain how we extract the 3D geometry from images, establish a relationship of 3D geometries from multiple images and adequate classification methods of images at the upper layers. Figure 4 shows the flow chart for a hierarchical representation method of an image set. With SIFT, RANSAC, the epipolar geometry and 3D camera position of a set of online images is estimated as shown in Figure 4. The lowest layer of our hierarchical structure is constructed using the 3D geometry of the images. In a next step, we describe the clustering of images based on the distance of each 3D camera position within the world coordinate system.

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Yoon, Sang Min; Graf, Holger

Eye Tracking Based Interaction with 3D Reconstructed Objects

2008

ACM SIGMM: Multimedia 2008 : Proceedings of the 2008 ACM International Conference on Multimedia. New York: ACM, 2008, pp. 841-844

ACM International Conference on Multimedia (MM) <16, 2008, Vancouver, BC, Canada>

This paper presents a method on how users might interact with objects which have been reconstructed from multiple images. Tracking the user's eye movement for HCI in an augmented reality environment provides a convenient, natural, and high-bandwidth source for navigating and zooming in/out of the 3D reconstructed object. The calculated 3D eye position, which is detected by multiple cues from a stereo camera, is synchronized with the 3D position of 3D reconstructed object. Our proposed method of image based 3D modelling is based on voxel carving with photo consistency check. Experimental results show that our proposed interaction methodology using a new solution of 3D eye tracking can be successfully applied for useful tools in context aware applications and improve its usability.

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Dzomo, Prudence Christelle; Graf, Holger (Betreuer)

Modellierung eines Mapping in einer multidisziplinären Umgebung zur effizienten Cross-Skill Engineering Kollaboration

2008

Darmstadt, TU, Diplomarbeit, 2008

Diese Arbeit behandelt einen neuen Ansatz einer disziplinübergreifenden Kooperation zwischen den Bereichen Konstruktion und Berechnung im Umfeld der Entwicklung mechatronischer Produkte. Die Arbeit soll Aufschluss über neue Möglichkeiten der multi-domänen Kollaboration und des Cross-Skill Engineerings geben. Im Schwerpunkt untersucht die vorliegende Arbeit geeignete und einheitliche Abstraktionsformen, die eine entsprechende Modellierung von Abbildungsvorschriften in bereichsübergreifenden Ingenieurstätigkeiten und Sichten ermöglichen. Im speziellen wird eine Lösung erarbeitet zur semi-automatischen Ableitung von Verhaltensmodellen mechatronischer Produkte. Diverse Produktsichten (CAD, FEM, Verhalten) individueller Bereiche werden abstrahiert und über geeignete Mechanismen ineinander überführt. In der Tat werden verschiedene Modelle, sog. Partialmodelle (z.B. CAD, FEM, Verhaltensmodell) in einzelnen Entwicklungsdomänen des Produktentwicklungsprozesses erstellt. Diese Partialmodelle stellen dabei eine Sicht des Gesamtprodukts dar. Dementsprechend werden die für die jeweilige Domäne relevanten Eigenschaften erfasst, abgebildet und verarbeitet, und andere, weniger relevanten, gar nicht betrachtet. In der Praxis werden die Informationen zwischen den im Entwicklungsprozess beteiligten Domänen nur periodisch ausgetauscht. Dies liegt einerseits daran, dass alle Partialmodelle nicht zum selben Zeitpunkt zur Verfügung stehen. Darüber hinaus ist die automatische Aktualisierung der Produktsichten (Partialmodelle) durch die Diversifizierung der Informationsmodelle nicht möglich. Dadurch ist die für einen nahtlosen Entwicklungsprozess erforderliche Konsistenz der Daten nicht durchgängig gewährleistet. Die erarbeiteten Ansätze zur Verbesserung der Kollaboration zwischen Konstruktion (CAD) und Berechnung (Verhaltensmodell, FEM) erstrecken sich auf mindestens drei Ebenen: Die erste Ebene adressiert eine Abstrahierung der Produktsichten (CAD, FEM- und Verhaltenmodell) ein. Aus den Abstraktionen werden Ähnlichkeiten und Diskrepanzen ermittelt. Auf der nächsten Ebene werden die erarbeiteten Abstraktionen genutzt, um Verhaltensmodelle aus CAD-Modellen automatisch zu generieren. Zum Nachweis des erarbeiteten Konzepts wird der CAMAT (CATIA-MATLAB-Translator) zur Generierung von MATLAB/SimMechanik-Modellen aus CATIA V5-Modellen entwickelt. Damit soll sichergestellt werden, dass die Partialmodelle frühzeitig zur Verfügung stehen. Die dritte Ebene der Kollaboration in dieser Arbeit berücksichtigt den Informationsaustausch zwischen den Partialmodellen. Hier wird eine Kollaborationsplattform entwickelt, welche eine Simulation zwischen CAD- und Verhaltensmodell ermöglicht. Aktoren im Verhaltensmodell steuern die Bewegungen (Roboterbewegung, Schlittenbewegungen) im CAD-Modell. In der interaktiven Simulationsumgebung werden die erhaltenen Bewegungssimulationen visualisiert, welche basierend auf den Soll-Ist-Wert Vergleichen der Simulationsengine das Verhalten der digitalen Prototypen darstellt.

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Yoon, Sang Min; Graf, Holger

Similarity Measure of the Visual Features Using the Constrained Hierarchical Clustering for Content Based Image Retrieval

2008

Bebis, George (Ed.) et al.: Advances in Visual Computing. Proceedings Part II : ISVC 2008. Berlin, Heidelberg, New York: Springer, 2008. (Lecture Notes in Computer Science (LNCS) 5359), pp. 860-868

International Symposium on Visual Computing (ISVC) <4, 2008, Las Vegas, NV, USA>

In this paper, we present a methodology on how to measure the visual similarity between a query image and hierarchically represented image databases for content based image retrieval. The images in database are hierarchically summarized and classified by recovered extrinsic camera parameters as well as constrained agglomerative clustering methods. The constrained agglomerative hierarchical image clustering method whose strategy is to extract a multi-level partitioning and grouping of multiple images is used for balancing the hierarchical trees and summarization. The visual codebooks which are hierarchically quantized in the clusters are used to calculate the similarity measure with a query image's visual features. Our proposed visual similarity measure and summarization of image data provide a very efficient way for searching and retrieving the images that have similar visual contents and geometrical location.

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Graf, Holger; Peña Serna, Sebastian; Stork, André

Towards Conceptual Simulations within Highly Interactive Environments

2007

Arabnia, Hamid R. (Ed.): Proceedings of the 2007 International Conference on Modeling, Simulation & Visualization Methods : MSV 2007. Las Vegas: CSREA Press, 2007, pp. 108-114

International Conference on Modeling, Simulation & Visualization Methods (MSV) <2007, Las Vegas, NV, USA>

During the last few years, 3D interactive tools, such as Virtual Reality have been accepted by several application domains e.g. design and engineering. Nowadays Virtual Reality environments are used for design review purposes, visualization of large data sets or immersive simulations, but have been limited to single domains. Generative tools offer the possibility for new applications in design environments, whereas 4D representations in the engineering domain become feasible at interactive rates (> 30 Hz). This new capabilities increase the expectations of engineers towards fast "whatif" analysis, in which several aspects of the product validation can be tested in interactive sessions. Thus, the aim is to bridge the gap between traditionally separated design and engineering domains, in order to allow Conceptual Simulations for validating and improving the design from an engineering point of view (Design by Simulation). Therefore, we present a new approach and methodologies, which build the fundaments of this concept.

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Leon, Jean-Claude; Giannini, Franca; Falcidieno, Bianca; Brunetti, Gino; Graf, Holger; Stork, André; Vexo, Frederic; Thalmann, Daniel

Acquiring, Structuring Shapes and Annotating Them with Semantics to Improve Design Activities

2006

Fischer, Xavier (Ed.) et al.: Research in Interactive Design : Proceedings of Virtual Concept 2005. Paris, Berlin, Heidelberg: Springer, 2006, 10 p.

Virtual Concept <2005, Biarritz, France>

Shapes incorporate geometry as well as semantics and can be defined in 2D, 3D or higher dimensions. Geometric models can be structured in such a way that they can provide a relevant framework to insert semantic information or view dependent information about a product to from features. Combining such features with an immersive environment allows the user to interact more efficiently with an object. This framework will be illustrated in the context of free-form surface modelling for aesthetic design and in the context of engineering and simulation, both among the research themes of the network of excellence AIM@SHAPE. Virtual environments can also contribute to the efficiency of the design process through appropriate models of interaction between the objects contributing to a given simulation environment (a maintenance task, a surface deformation process for aesthetic design for example). To this end, virtual humans bring new capabilities to enhance simulations though they require new models of interaction to incorporate the appropriate semantics during an object manipulation. This third aspect is also part of the ongoing research actions of AIM@SHAPE and will be addressed to show how it is complementary to the previous one. As a result, this set of contributions demonstrates how various categories of semantic can enhance the design process within virtual environments.

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Graf, Holger; Peña Serna, Sebastian; Stork, André

Adaptive Quality Meshing for "On-the-fly" Volumetric Mesh Manipulations within Virtual Environments

2006

IEEE Instrumentation and Measurement Society: VECIMS 2006 : Proceedings of 2006 IEEE International Conference on Virtual Environments, Human-Computer Interfaces and Measurement Systems. New York: IEEE, Inc., 2006, pp. 178-183

IEEE International Conference on Virtual Environments, Human-Computer Interfaces and Measurement-Systems (VECIMS) <4, 2006, La Coruña, Spain>

This paper presents a new approach for interactive 3D (volume) mesh manipulations based on 'on-the-fly' quality measures in order to keep the consistency of the mesh. Within pure engineering tasks, such as the analysis of physical behaviour, virtual environments only established as post processing unit, in which simulation results can be interactively displayed and visualized to get more in depth information about the simulation mock up. However, most of the simulations are done off-line which do not allow for interactive 'what-if' analysis in view of a change of the primary design domain. As design changes of the underlying CAx/FE models usually imply many manual interferences, repair and efforts (re-meshing tasks, grid repair, etc.) in order to guarantee elements of high quality during re-meshing or mesh refinement tasks, an evaluation within virtual environments is not suitable with current techniques. Thus this paper aims at introducing our approach in order to change 3D volumetric meshes on the fly and keep the consistency of the newly generated mesh in view of engineering analysis.

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Peña Serna, Sebastian; Graf, Holger (Betreuer)

Towards Conceptual Simulations for Linear Elasticity Analysis: Final Report Presented to Obtain the International Certificate in New Media Technology (ICPNM).

2006

Darmstadt, 2006

This project aims at developing a novel feature movement mechanism for Finite Element Analysis (FEA) meshes through a haptic pen (Phantom stylus) within a Virtual Reality (VR)-based environment. The tools developed in this project allow for making real-time feature movements and gesture-based manipulations on surface and volume meshes which lead to "what-if-analysis" on the fly. Focus of the work is the real-time operation in highly resources and computing intensive envision meshes. The approach here presented might enable the project to head towards conceptual simulations within the engineering domain (targeting at linear static analysis). Methodologies are presented for interactive mesh modifications within linear static problems based on tetrahedral meshes, 'on-the-fly' feature movements (such as through holes), the adaptation of the surrounding volume mesh, fast and adaptive mesh refinement techniques, quality measures to ensure the consistency and quality of the newly, 'on-the-fly' generated elements and the necessary topological operations for unstructured triangular tetrahedral mesh. Because of the interactive environment, all operations have to comply with the real-time constrain and have to be evaluated for local simplicial elements. In order to reduce the analysis and computation overhead, a new idea was introduced for local evaluations based on an integrated submodeling procedure. From global to local and coarse to fine, here additional constrains like influence and consistency on/with the overall model have to be considered. The approach take essential boundary conditions into account which constrain the isolated part of the submodel and which are derived from the global solution. Within the engineering environments, the explicit and implicit methodologies from global to locally detailed analysis (from coarse to refined results) allows the approach to head for fast preliminary design evaluations. The project has relevance for the computer graphics field because it will offer human interaction with feedbacks for real-time applications, supporting industrial applications. In the same way, the industrial companies (like aircraft and automobile manufacturers) could take benefit of the results, since it supports engineers with tools for conceptual simulations and shortening analysis cycles, reducing cost and time to market.

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Graf, Holger; Stork, André

Bridging the Gap between CAD/CAE and VR and Incorporating Semantics into the Analysis Process

2005

ProSTEP iViP Association: ProSTEP iVip Science Days 2005 : Cross-Domain Engineering. Bobingen: Kessler Verlagsdruckerei, 2005, pp. 260-261

ProSTEP iVip Science Days <2, 2005, Darmstadt, Germany>

The numerous engineers, technicians and supportive staff taking part in the design process have an impact on the structure and the content of Computer Aided Design (CAD), Computer Aided Engineering (CAE) and other CAx tools. Bringing in different levels of knowledge within different areas they contribute to a diversity of data. Currently available software is capable of fast manipulation of an ever increasing amount of information. The representation of objects within an engineering design environment uses extensively geometric aspects, whereas physical attributes assigned to geometric parts are more important to the analysts. However, during the design and analysis process, various representations of the same objects are generated and used, i.e. geometric, technological, mechanical representations, representation for manufacture, etc. involving multiple downstream applications which have to make use of similar object representations of the same design. Especially in the CAE domain current workflow lacks of significant deficiencies resulting from data exchange or adequate model representations fit for analysis. A repair/healing of the CAD model, the removal of features which are irrelevant for the analysis or even design idealisations lead to significant manual overhead during the preparation stage of the CAE process. Thus, the process of an appropriate preparation of a data model to an adequate result is time consuming and error-prone. Estimates in classical simulation (FEA/CFD) environments assume that according to the problem more than 50% of the workload is needed for data acquisition. As soon as the model is available 90% of the time needed for an appropriate digital analysis is modeling and results evaluation. Only 10% of the workload is estimated for the execution of the simulation run. These estimates do not take into account interactive modifications of the simulation. In order to enhance the integration of CAD/CAE and VR different tools emerged in the past decade allow a semi-automated way of domain decomposition, feature based modelling, fast and efficient post processing. However, still significant work has to be done in order to achieve an efficient analysis turn around.

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Benölken, Paul; Graf, Holger

Direct Volume Rendering of Unstructured Grids in a PC Based VR Environment

2005

Skala, Vaclav (Ed.): Journal of WSCG Volume 13 No. 1-3, 2005. Proceedings. Plzen: University of West Bohemia, 2005, pp. 25-32

International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG) <13, 2005, Plzen, Czech Republic>

In this paper we present our solution for fast, direct volume rendering of unstructured grids on standard PC workstations. We describe our modification of the incremental slicing approach for achieving high performance as well as our implementation of geometry-compression methods for minimizing the memory requirements. Furthermore, we show our implementation for the interactive modification of transfer functions (classification) in a virtual reality environment by using 3D interaction widgets.

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Graf, Holger; Wundrak, Stefan; Göllner, Carlo Moritz; Stork, André

Hybrid Objects - A Concept for the Seamless Integration of 2D and 3D User Interfaces

2005

HCI International 2005. [Proceedings CD-ROM]. Mahwah, New Jersey: Lawrence Erlbaum Associates, Inc., 2005, 10 p.

International Conference on Human-Computer Interaction (HCII) <11, 2005, Las Vegas, NV, USA>

VR systems are nowadays established in many areas. However, even in environments where VR is widely accepted, users spend the bigger part of their time working at classic desktops with WIMP (windows, icons, menus, pointers) interfaces. When switching to a VR-Setup the user usually also switches to a different application and thus needs time to familiarize with the software. For this reason we introduce a concept of HCI that is based on 3D widgets (hybrid objects) that are designed in such a way that with no or only slight modification 2D interaction is also possible. Thus, the same application can be used in 2D as well as in 3D. Furthermore, we introduce the Hybrid Desktop, a 2D/3D desktop VR configuration that is optimal for the hybrid objects concept. Finally, we describe a user test to show that skills learned on a application running on a desktop computer can be transferred to the same application running on VR hardware due to the consistent user interface.

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Graf, Holger; Wundrak, Stefan; Stork, André

The Hybrid Desktop within Engineering Environments

2005

HCI International 2005. [Proceedings CD-ROM]. Mahwah, New Jersey: Lawrence Erlbaum Associates, Inc., 2005, 8 p.

International Conference on Human-Computer Interaction (HCII) <11, 2005, Las Vegas, NV, USA>

Especially in the area of engineering applications different requirements are imposed to the usability and acceptance of new and innovative systems. A very pragmatic approach is the seamless integration into the existing environment. This paper presents a new hybrid 2D/3D system based on virtual reality that was developed in the multidisciplinary context of engineering applications. The 'Hybrid Desktop' has been realised to integrate CAD/CAE and VR review processes (which are traditionally separated disciplines) into one working environment. Beside traditional and new 6DOF devices, innovative interaction concepts have been developed in order to address the need for a seamless integration of commercial software and virtual reality systems. The Hybrid Desktop offers a new low cost based working place based on virtual reality within the engineering context. The paper highlights the realisation of a hybrid 2D/3D environment driven by engineering needs to combine multidisciplinary applications at one working place. It furthermore describes the software architecture necessary for the realisation of an integrated working space. Engineers within the automobile, aerospace and urban planning area, have proofen the usability of our approach for an effective engineering environment.

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Graf, Holger; Wundrak, Stefan; Stork, André

Towards Desktop-based VR for Engineering Environments Driven by Autostereoscopic Technology

2005

ProSTEP iViP Association: ProSTEP iVip Science Days 2005 : Cross-Domain Engineering. Bobingen: Kessler Verlagsdruckerei, 2005, pp. 158-169

ProSTEP iVip Science Days <2, 2005, Darmstadt, Germany>

Current engineering requirements focus on the integration of different services, technologies and products. Especially within the CAD/CAE domain the different disciplines of construction and analysis are traditionally separated. An integration of the process chain being complemented by innovative technologies such as Virtual Reality (VR) is one of the challenges that is addressed in this work. We set the foundations for an integrated CAD/CAE environment covering such topics as small feature identification, interactive mesh refinement, and interactive feature dragging. Interactive 3D real-time graphics is one way to analyse and interact on the ever growing CAD/CAE data more efficiently and more intuitively. VR applications have shown its power in this respect already. However, compared to desktop systems the number of VR installations in the industry is still low. This is on the one hand due to high investment costs and space demands of typical VR hardware and on the other hand due to the users lack of acceptance for entirely new 3D user interfaces. In this work we use low-cost desktop VR systems based on autostereoscopic displays (Hybrid Desktop) together with a concept of 2D/3D interaction that promises a higher user acceptance.

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Graf, Holger; Stork, André; Bouvier, Eric; Balet, Olivier

A Hybrid 2D/3D Interaction Device Steering Distributed Hybrid Applications

2004

Institute of Electrical and Electronics Engineers (IEEE): Beyond Wand and Glove Based Interaction : IEEE VR 2004 Workshop: Participant's Edition. Los Alamitos, Calif.: IEEE Computer Society, 2004, pp. 55-59

IEEE Virtual Reality (VR) Workshop <2004, Chicago, Illinois, USA>

This paper presents a new system based on a wireless 6DOFs interaction device, which is able to combine both traditional interaction possibilities that are required by common legacy point-and-click applications, with immersive point-and-interact techniques within a virtual environment. This device, associated with both standard and stereoscopic displays connected to their respective computers, defines an innovative type of distributed platform which is directly compatible with traditional legacy applications that can be augmented with an immersive environment, enabling the user to steer and control hybrid 2D/3D environments. Those concepts are illustrated by presenting an application that we are developing in the multidisciplinary context of engineering, a typical situation in which supporting the pre-existing user's environment is mandatory for the take-up and acceptance of innovative techniques from virtual reality.

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Graf, Holger; Koch, Marianne; Stork, André; Barski, Olaf

Cyberstilo©. Towards an Ergonomic and Aesthetic Wireless 3D-Pen

2004

Institute of Electrical and Electronics Engineers (IEEE): Beyond Wand and Glove Based Interaction : IEEE VR 2004 Workshop: Participant's Edition. Los Alamitos, Calif.: IEEE Computer Society, 2004, pp. 51-54

IEEE Virtual Reality (VR) Workshop <2004, Chicago, Illinois, USA>

This paper presents the development of a new wireless interaction device named Cyberstilo©. Virtual environments have matured during the last decade providing sophisticated solutions for exploring and experiencing 3D space in a more intuitive and natural way. Adequate interaction devices allowed the user to manipulate objects and navigate efficiently through space although having been designed for specific application scenarios. However, with its maturity new application areas of virtual reality target at multidisciplinary fields, where cultural, aesthetical, ergonomical, technical, functional and commercial requirements are becoming more important. Especially for designers aesthetics and ergonomics play an important role during the styling phase. The Cyberstilo© was specifically designed for combining ergonomical and aesthetical characterristics of interaction devices which are missing in the state-of-the-art of interaction devices.

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Wolff, Alexander; Graf, Holger (Betreuer)

Echt-Zeit FEA basierend auf Elementmaskierungen zur interaktiven VR-Analyse im industriellen Umfeld

2004

Darmstadt, TU, Diplomarbeit, 2004

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Benölken, Paul; Graf, Holger; Stork, André

Texture-Based Flow Visualization in Augmented and Virtual Reality Environments

2004

Skala, Vaclav (Ed.) et al.: WSCG 2004 [CD-ROM] : Full Papers, Short Papers, Posters. Plzen: University of West Bohemia, 2004, pp. 21-24

International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG) <12, 2004, Plzen, Czech Republic>

Virtual and Augmented Reality allows a new way of result exploration of numerical simulations, its analysis and interpretation by immersing the user into the data sets and/or by keeping the relationship and context to the real environment. Up to date only a few approaches targeting the deployment of augmented reality during the analysis stage have been published. The handling of large data sets at interactive rates becomes a crucial bottleneck and influences the successful introduction for augmented reality solutions within this area. The data exploration using different VR based solutions have shown how to ease the understanding and interpretation of complex 3D data sets using stereoscopic presentations of vector glyphs, path-, stream, streak lines or surfaces. New texture based visualization tools emerged and conciliate a better understanding of the flow fields. In this paper we describe our approach for the integration of texture based visualization methods within a mixed reality set-up during the analysis stage by introducing a 'low cost', fully 3D interactive post processing unit for large CFD data sets.

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Santos, Pedro; Fleisch, Timo; Graf, Holger; Stork, André

3D Interactive Augmented Reality in Early Stages of Product Design

2003

Jacko, Julie A. (Ed.) et al.: HCI International 2003. Proceedings of the 10th International Conference on Human-Computer Interaction. Volume 4 : Inclusive Design in the Information Society. Mahwah, New Jersey: Lawrence Erlbaum, 2003, pp. 1203-1207

International Conference on Human-Computer Interaction (HCII) <10, 2003, Crete, Greece>

Augmented Reality (AR) allow the combination of virtual and physical models, making use of visualised objects that are displayed into the field of view of the user overlaying the physical prototype. Though being inspired by the application of VR technology, AR lacks of similar shortcomings, e.g. missing of 3D interactive modelling functionalities. Hence, AR is mainly found in the late stages of product development (e.g. maintenance, training) rather than in early stages of product design where objects have to be interactively generated or modified. New approaches in 3D interaction methods for generic 3D tasks, allow the application of AR technology in early stages of product design. This paper shows how physical and virtual prototypes could be beneficially combined in a highly 3D-interactive and generic environment, thus contributing to an improvement of this stage. It furthermore highlights first applications, e.g. 3D virtual tape drawing with a two-handed 3D interactive technique in an AR set-up, in this area.

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Benölken, Paul; Graf, Holger; Stork, André

Exploring Flow Fields in Augmented Reality Environments

2003

First Research Workshop on Augmented Virtual Reality (AVIR). Proceedings : Workshop Notes. Genf, Schweiz, 2003, p. 36-38

Research Workshop on Augmented Virtual Reality (AVIR) <1, 2003, Genf, Schweiz>

Specifically during the analysis and optimization stage within the product development process, e.g. in crash tests, structural optimization or flow simulations, VR techniques contributed to a minimum number of physical models in use and enhanced the evaluation stage. As a co-existence between virtual reality techniques and physical prototypes especially within this stage during product development will build the basis for further developments and research efforts, the adoption of augmented reality opens up new challenges to the research community. AR allows a new way of result exploration, its analysis and interpretation by keeping the relationship and context to the real environment. Up to date only a few approaches targeting the deployment of augmented reality during the analysis stage have been published. This is due to the nature of numerical simulations which burden further requirements to the usability of an AR based solution. The handling of large data sets at interactive rates becomes a crucial bottleneck and influences the successful introduction for augmented reality solutions within this area. In this paper we describe our approach for the use of AR during the analysis stage by introducing a "low cost", fully 3D interactive post processing unit for large CFD data sets around a physical mock-up.

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Graf, Holger; Brunetti, Gino; Stork, André

A Methodology Supporting the Preparation of 3D-CAD Data for Design Reviews in VR

2002

Marjanovic, Dorian (Ed.): Proceedings of the 7th International Design Conference. Zagreb: Faculty of Mecanical Engineering and Naval Architecture, University of Zagreb, 2002, pp. 489-495

International Design Conference (DESIGN) <7, 2002, Dubrovnik, Croatia>

In recent years a range of different VR applications have been developed for the purposes of design review and analysis. The typical data source for a design review of complex models using VR technologies is an underlying 3D-CAD system or 3D styling tool, that provides geometric and topological information of the digital model. The time to adequately prepare 3D-CAD data for a design review session using VR is inherently influenced by the underlying methodology of product modelling, data acquisition, the quality of the conversion and complexity of the digital model. To manually prepare the data without an automated mechanism is tedious and cumbersome. Thus, we describe an efficient methodology and architecture to automate the process of data preparation for the purposes of a design review session in VR.

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Graf, Holger; Santos, Pedro; Stork, André

Augmented Prototyping - Combining Physical and Virtual Prototypes Advantageously/ Beneficially

2002

Meyer, Rudolf et al.: Euro-uRapid 2002. International User's Conference on Rapid Prototyping & Rapid Tooling & Rapid Manufacturing. Proceedings : High Tech Solutions and Concepts. Frankfurt/Main, 2002, B-1/2, 7 p.

International User's Conference on Rapid Prototyping & Rapid Tooling & Rapid Manufacturing (uRapid) <2002, Frankfurt/Main, Germany>

Immersive real-time visualisation of complex product models has been widely used within the engineering domain. In recent years a range of different VR applications have been developed for the purposes of design review and analysis. The development of virtual reality techniques lead to a significant reduction of physical models though not replacing them completely within the product development process. Specifically during the analysis and optimisation stage, e.g. in crash tests, structural optimisation, VR techniques contributed to a minimum number of physical models in use. A complete replacement of physical prototypes with its virtual counterpart though, will not be possible within the near future. Hence, a co-existence between virtual reality techniques and physical prototypes in different application areas during the development process will build the basis for further developments. This paper shows how physical and virtual prototypes could be beneficially combined, thus contributing to an improvement of the rapid product development (Augmented Prototyping).

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Graf, Holger; Brunetti, Gino; Stork, André

CAD2VR or How to Efficiently Integrate VR into the Product Development Process

2002

Stelzer, Ralph H. (Ed.) et al.: CAD 2002. Proceedings : Corporate Engineering Research. Bonn: GI, 2002, pp. 249-258

CAD <2002, Dresden>

Immersive real-time visualisation of complex product models has become widely used for design review within the engineering domain. In recent years a range of different VR applications have been developed for the purposes of design review and analysis. The typical data source for a review session of complex models using VR technologies is an underlying 3D-CAD system or 3D styling tool, that provides geometric and topological information of the digital model. Most of the CAD models contain digital information which is redundnt for the purposes of a VR environment. Neverthelless, the pre-processing and data preparation step is time consuming and error prone. Tedious manual data preparation and correction is still widespread and seek sfficient mecanis to automate the turn around cycles of CAD to VR sessions. Hence, we describe an efficient methodology and architecture to automate the process of data preparation for the purposes of a design review in VR.

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Benölken, Paul; Graf, Holger

Interaktive Erkundung von CAE- Welten

2002

CAD-CAM REPORT, Vol.21 (2002), 5, pp. 60-63

Business-to-business (B2B) und Collaborative Product Commerce (CPC) sind zur Zeit die treibenden Faktoren im CAx Markt. Dabei steht heute die digitale Produktrepräsentation (digitaler Prototyp) im Mittelpunkt von Geschäftsprozessen und -entscheidungen. Wie bereits im DMU-Umfeld und im Design-Review weitestgehend etabliert, werden heute aufgrund von 3D-CAD Modellen strategische Entscheidungen getroffen. Innovative Präsentations- und Interaktionstechnologien wie Virtual- und Augmented Reality Techniken spielen hier eine zunehmend wichtigere Rolle. Allerdings beschränkt sich deren z.Z. weitestgehend auf den Design Bereich, womit das enorme Potential dieser Technologien bei weitem noch nicht ausgeschöpft ist. Tatsächlich beinhaltet das Engineering eine Vielzahl weiterer Aufgaben die über den reinen Konstruktions- und Designprozeß hinausreichen. Eine besondere Bedeutung kommt der Analyse und Optimierung digitaler und realer Prototypen zu. Numerische Simulationen spielen hierbei eine besondere Rolle und sind heute aus dem täglichen Geschäft des Ingenieurs nicht mehr wegzudenken. Physikalische/Mechanische Problemstellungen werden dabei mit Hilfe numerischer Berechnungs- und Lösungsverfahren bearbeitet. Das Ziel ist dabei zum einen bestehende Produkte zu optimieren und zum anderen eine Vorhersage über vielfältige Eigenschaften neuer Produkte zu treffen. Mit der rasant entwickelten Leistungsfähigkeit und Kapazität aktueller Hardwareumgebungen können mittlerweile neben verschiedene Simulationen auch zahlreiche Messungen in immer kürzeren Zeiträumen und mit steigender Genauigkeit durchgeführt werden. Die Herausforderung stellt sich hierbei in der Verarbeitung, Interpretation und Kommunikation der hieraus resultierenden riesigen Datenmengen. Die Interpretation solch gewaltiger Zahlenkolonnen ist ohne den Einsatz visueller Hilfsmittel heute kaum denkbar. Hieraus ergeben sich die wesentliche Aufgaben und Anforderungen an eine rechnerbasierten Visualisierung. Die Aufgaben bestehen in diesem Umfeld zum Einen in der Unterstützung des Anwenders bei der Generierung von Hypothesen (z.B. bei der Interpretation von Messdaten), deren Validierung sowie in der Kommunikation und schließlich der Präsentation von Ergebnissen. Die Anforderungen ergeben sich zum einen aus der Mächtigkeit und Komplexität der darzustellenden Daten und dem Anspruch an Echtzeitfähigkeit/Interaktionsfähigkeit und Vollständigkeit zum anderen. Durch die Bereitstellung innovativer und interaktiver Visualisierungstechniken kann ein Ingenieur in sinnvoller Weise unterstützt werden. Virtual Reality Techniken ermöglichen es hierbei komplexe Sachverhalte in verständlicher und zeitsparender Form zu validieren und zu präsentieren. Zum gegenwärtigen Zeitpunkt werden die verschiedenen Visualisierungs- und Interaktionstechniken weitestgehend für die Verarbeitung und Analyse bereits abgeschlossener numerischer Simulationen (Post-Processing) genutzt. Auf diese Weise können die Auswirkungen, selbst minimaler Modifikationen, am digitalen Prototypen, erst nach vollständiger Beendigung der Prozesskette, bestehend aus Konstruktion, Vorverarbeitung, Simulation und Visualisierung beurteilt werden. Diese Vorgehensweise ist natürlich sehr Zeitaufwendig zumal sich irrelevante oder fehlerhafte Simulationsverläufe erst am Ende der Prozesskette erkennen lassen. Eine direkte, VR-gestützte Interaktion mit der Simulation bei gleichzeitiger Darstellung der Ergebnisse würde somit enorm zur Verbesserung des gesamten Entwicklungsprozesses beitragen ist daher nach wie vor Gegenstand aktueller Forschungs- und Entwicklungsvorhaben. In diesem Beitrag werden daher die wichtigsten z.Z. eingesetzten interaktiven Methoden und Werkzeuge vorgestellt und ein Ausblick auf weitere innovative Visualisierungstechniken gegeben.

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Benölken, Paul; Bossong, Ulrike; Graf, Holger

VISICADE - interactive Simulationen in integrierten Prozessen

2002

ProduktDaten Journal, Vol.9 (2002), 2, pp. 38-41

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Benölken, Paul; Graf, Holger; Rix, Joachim

Interactive Visualization Techniques for a Virtual Reality Based Analysis of Simulation Results

2001

Korea Society for Simulation (KSS): SeoulSim 2001. Proceedings, pp. 237-247

The Seoul International Simulation Conference <1, 2001, Seoul, Korea>

In this paper we present an overview of existing state of the art visualization techniques for the interactive analysis of results from numerical simulations and measurements. We describe the basic concepts and key ideas behind these different visualization methods in this paper. The potential of these techniques for an efficient integration into a virtual reality environment will be investigated. Furthermore we present our first demonstrator for visualizing multiparametric data and give an outlook on our plans for further exploiting and developing these techniques in an upcoming project.

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Brunetti, Gino; Graf, Holger; Alves dos Santos, Luiz M.

Virtual Reality Techniques Supporting the Product and Process Development

2000

Schützer, Klaus (Ed.): Anais do 5 Seminário Intenacional de Alta Tecnologia : Inovações Tecnológicas no Desenvolvimento do Produto. Piracicaba: UNIMEP, 2000, pp. 83-98

Seminário Intenacional de Alta Tecnologia <5, 2000, Piracicaba, Brazil>

Information technology is more and more used in the product and process development. Especially virtual reality techniques are supporting the man/machine interaction as well as the dialog among the users within the process chain. Co-operation, communication, and co-ordination are calling for support through such techniques to fulfil the requirements of the market in this application area. Modelling with 3D interaction techniques, presentation of simulation results, and virtual environments to experience, analyse, evaluate, and manipulate the products and processes are the major application scenarios today. This paper will introduce to the current state of the art of applying virtual reality techniques to the different aspects of the product development process and give an overview of the corresponding activities at the Fraunhofer-IGD.