Dr. Matthias Trapp

Contact

Tel.: +49-(0)331 5509-3913
Fax: +49-(0)331 5509-172
Room: H-2.28
Email: matthias.trapp(at)hpi.de

Research Interests

I'm a senior researcher, principle investigator and lecturer. My research interests include the following topics:

GPU-based image and video processing techniques and frameworks
Interactive GPU-based rendering techniques for massive spatio-temporal data
Focus+context visualization techniques for 3D virtual environments
Web-based visualization for mobility analytics
Interactive software maps

We also offer topics for master theses.

Current Research Projects

PunctumTube: Analytics Platform for Digital Twins based on 3D Point Clouds
mdViPro: Multi-dimensional Videoprocessing

Past Research Projects

Automatic Video Abstraction
Service-based Mobility Analytics
Research Group 4DnD-Vis
Business Intelligence Maps
3D Geoinformation
Interactive 3D Visualization of Roman Cologne
PROGRESS
DigiPolis
Virtual Rendering System

Publications

A Taxonomy of Treemap Visualization Techniques.Scheibel, Willy; Trapp, Matthias; Limberger, Daniel; Döllner, Jürgen (2020).
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AbstractA treemap is a visualization that has been specifically designed to facilitate the exploration of tree-structured data and hierarchically structured data. The family of visualization techniques that use a visual metaphor for parent-child relationships based "on the property of containment" (Johnson, 1993) is commonly referred to as treemaps. However, as the number of variations of treemaps increases, it becomes increasingly important to distinguish clearly between techniques and their specific characteristics. This paper proposes to discern between Space-filling Treemap T_S , Containment Treemap T_C , Implicit Edge Representation Tree T_IE , and Mapped Tree T_MT for classification of hierarchy visualization techniques and highlights their respective properties. This taxonomy is created as hyponymy, i.e., its classes have an is-a relationship to each other: T_S ⊂ T_C ⊂ T_IE ⊂ T_MT . With this proposal, we intend to stimulate a discussion on a more unambiguous classification of treemaps and, furthermore, broaden what is understood by the concept of treemap itself.
Controlling Image-Stylization Techniques using Eye Tracking.Söchting, Maximilian; Trapp, Matthias (2020).
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AbstractWith the spread of smart phones capable of taking high-resolution photos and the development of high-speed mobile data infrastructure, digital visual media is becoming one of the most important forms of modern communication. With this development, however, also comes a devaluation of images as a media form with the focus becoming the frequency at which visual content is generated instead of the quality of the content. In this work, an interactive system using image-abstraction techniques and an eye tracking sensor is presented, which allows users to experience diverting and dynamic artworks that react to their eye movement. The underlying modular architecture enables a variety of different interaction techniques that share common design principles, making the interface as intuitive as possible. The resulting experience allows users to experience a game-like interaction in which they aim for a reward, the artwork, while being held under constraints, e.g., not blinking. The conscious eye movements that are required by some interaction techniques hint an interesting, possible future extension for this work into the field of relaxation exercises and concentration training.
Sensor Data Visualization for Indoor Point Clouds.Stojanovic, Vladeta; Trapp, Matthias; Hagedorn, Benjamin; Klimke, Jan; Richter, Rico; Döllner, Jürgen (2019).
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Interactive Close-Up Rendering for Detail+Overview Visualization of 3D Digital Terrain Models.Trapp, Matthias; Döllner, Jürgen (2019).
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AbstractThis paper presents an interactive rendering technique for detail+overview visualization of 3D digital terrain models using interactive close-ups. A close-up is an alternative presentation of input data varying with respect to geometrical scale, mapping, appearance, as well as level-of-detail and level-of-abstraction used. The presented 3D close-up approach enables in-situ comparison of multiple region-of-interest simultaneously. We present a GPU-based rendering technique for the image-synthesis of multiple close-ups in real-time.
Semantic Enrichment of Indoor Point Clouds: An Overview of Progress towards Digital Twinning.Stojanovic, Vladeta; Trapp, Matthias; Richter, Rico; Hagedorn, Benjamin; Döllner, Jürgen in 37th eCAADe Conference (2019).
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Locally Controllable Neural Style Transfer on Mobile Devices.Reimann, Max; Klingbeil, Mandy; Pasewaldt, Sebastian; Semmo, Amir; Trapp, Matthias; Döllner, Jürgen in The Visual Computer (2019).
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URNhttp://dx.doi.org/10.1007/s00371-019-01654-1
ViVid: Depicting Dynamics in Stylized Live Photos.Semmo, Amir; Reimann, Max; Klingbeil, Mandy; Shekhar, Sumit; Trapp, Matthias; Döllner, Jürgen (2019). 8:1-8:2.
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URNhttp://dx.doi.org/10.1145/3305365.3329726
AbstractWe present ViVid, a mobile app for iOS that empowers users to express dynamics in stylized Live Photos. This app uses state-of-the-art computer-vision techniques based on convolutional neural networks to estimate motion in the video footage that is captured together with a photo. Based on these analytics and best practices of contemporary art, photos can be stylized as a pencil drawing or cartoon look that includes design elements to visually suggest motion, such as ghosts, motion lines and halos. Its interactive parameterizations enable users to filter and art-direct composition variables, such as color, size and opacity, of the stylization process. ViVid is based on Apple's CoreML, Metal and PhotoKit APIs for optimized on-device processing. Thus, the motion estimation is scheduled to utilize the dedicated neural engine and GPU in parallel, while shading-based image stylization is able to process the video footage in real-time. This way, the app provides a unique tool for creating lively photo stylizations with ease.
Generation of Approximate 2D and 3D Floor Plans from 3D Point Clouds.Stojanovic, Vladeta; Trapp, Matthias; Richter, Rico; Döllner, Jürgen (2019).
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In-Situ Comparison for 2.5D Treemaps.Limberger, Daniel; Trapp, Matthias; Döllner, Jürgen (2019).
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Rendering Procedural Textures for Visualization of Thematic Data in 3D Geovirtual Environments.Trapp, Matthias; Schlegel, Frank; Pasewaldt, Sebastian; Döllner, Jürgen (2019).
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Lens-based Focus+Context Visualization Techniques for Interactive Exploration of Web-based Reachability Maps.Listemann, Marc; Trapp, Matthias; Döllner, Jürgen (2019).
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AbstractReachability maps are powerful means to help making location-based decisions, such as choosing convenient sites for subsidiaries or planning vacation trips. Existing visualization approaches, however, introduce drawbacks concerning an effective acquisition of relevant information and an efficient data processing. In this paper, we introduce the first approach known so far to apply focus+context techniques to web-based reachability maps. We therefore propose a real-time enabled combination of an isochrone-based and a network-based representation of travel times obtained from multi-modal routing analysis using interactive lenses. We furthermore present a GPU-accelerated image-based method to compute isochrones based on a travel time-attributed network on client-side and thus achieve reduced data transmission efforts while yielding isochrones of higher precision, compared to generalized geometry-based approaches.
Techniques for GPU-based Color Quantization.Trapp, Matthias; Pasewaldt, Sebastian; Döllner, Jürgen (2019).
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AbstractThis paper presents a GPU-based approach to color quantization by mapping of arbitrary color palettes to input images using LUTs. For it, different types of LUTs, their GPU-based generation, representation, and respective mapping implementations are described and their run-time performance is evaluated and compared.
Semantic-driven Visualization Techniques for Interactive Exploration of 3D Indoor Models.Florio, Alessando; Trapp, Matthias; Döllner, Jürgen (2019).
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AbstractThe availability of detailed virtual 3D building models including representations of indoor elements, allows for a wide number of applications requiring effective exploration and navigation functionality. Depending on the application context, users should be enabled to focus on specific object-of-interests or important building elements. This requires approaches to filtering building parts and techniques to visualize important building objects and their relations. For it, this paper explores the application and combination of interactive rendering techniques as well as their semantically-driven configuration in the context of 3D indoor models.
Performance Evaluation and Comparison of Service-based Image Processing based on Software Rendering.Wegen, Ole; Trapp, Matthias; Döllner, Jürgen; Pasewaldt, Sebastian (2019).
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AbstractThis paper presents an approach and performance evaluation of performing service-based image processing using software rendering implemented using Mesa3D. Due to recent advances in cloud computing technology (with respect to both, hardware and software) as well as increased demands of image processing and analysis techniques, often within an eco-system of devices, it is feasible to research and quantify the impact of service-based approaches in this domain with respect to cost-performance relation. For it, we provide a performance comparison for service-based processing using GPU-accelerated and software rendering.
Real-time Screen-space Geometry Draping for Digital Terrain Models.Trapp, Matthias; Döllner, Jürgen (2019).
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AbstractA fundamental task in 3D geovisualization and GIS applications is the visualization of vector data that can represent features such as transportation networks or land use coverage. Mapping or draping vector data represented by geometric primitives (e.g., polylines or polygons) to 3D digital elevation or terrain models is a challenging task. We present an interactive GPU-based approach that performs geometry-based draping of vector data on per-frame basis using an image-based representation of a 3D digital elevation or terrain model only.
Occlusion Management Techniques for the Visualization of Transportation Networks in Virtual 3D City Models.Trapp, Matthias; Dumke, Fabian; Döllner, Jürgen (2019).
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Service-Oriented Processing and Analysis of Massive Point Clouds in Geoinformation Management.Discher, Sören; Richter, Rico; Trapp, Matthias; Döllner, Jürgen in Service-Oriented Mapping: Changing Paradigm in Map Production and Geoinformation Management, J. Döllner, Jobst, M., Schmitz, P. (reds.) (2019). 43--61.
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HerausgeberDöllner, Jürgen and Jobst, Markus and Schmitz, Peter
URNhttp://dx.doi.org/10.1007/978-3-319-72434-8_2
AbstractToday, landscapes, cities, and infrastructure networks are commonly captured at regular intervals using LiDAR or image-based remote sensing technologies. The resulting point clouds, representing digital snapshots of the reality, are used for a growing number of applications, such as urban development, environmental monitoring, and disaster management. Multi-temporal point clouds, i.e., 4D point clouds, result from scanning the same site at different points in time and open up new ways to automate common geoinformation management workflows, e.g., updating and maintaining existing geodata such as models of terrain, infrastructure, building, and vegetation. However, existing GIS are often limited by processing strategies and storage capabilities that generally do not scale for massive point clouds containing several terabytes of data. We demonstrate and discuss techniques to manage, process, analyze, and provide large-scale, distributed 4D point clouds. All techniques have been implemented in a system that follows service-oriented design principles, thus, maximizing its interoperability and allowing for a seamless integration into existing workflows and systems. A modular service-oriented processing pipeline is presented that uses out-of-core and GPU-based processing approaches to efficiently handle massive 4D point clouds and to reduce processing times significantly. With respect to the provision of analysis results, we present web-based visualization techniques that apply real-time rendering algorithms and suitable interaction metaphors. Hence, users can explore, inspect, and analyze arbitrary large and dense point clouds. The approach is evaluated based on several real-world applications and datasets featuring different densities and characteristics. Results show that it enables the management, processing, analysis, and distribution of massive 4D point clouds as required by a growing number of applications and systems.
Service-Oriented Semantic Enrichment of Indoor Point Clouds using Octree-Based Multiview Classification.Stojanovic, Vladeta; Trapp, Matthias; Richter, Rico; Döllner, Jürgen in Graphical Models, (J. Peters, red.) (2019).
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HerausgeberPeters, Jörg
URNhttp://dx.doi.org/10.1016/j.gmod.2019.101039
AbstractThe use of Building Information Modeling (BIM) for Facility Management (FM) in the Operation and Maintenance (O&M) stages of the building life-cycle is intended to bridge the gap between operations and digital data, but lacks the functionality of assessing the state of the built environment due to non-automated generation of associated semantics. 3D point clouds can be used to capture the physical state of the built environment, but also lack these associated semantics. A prototypical implementation of a service-oriented architecture for classification of indoor point cloud scenes of office environments is presented, using multiview classification. The multiview classification approach is tested using a retrained Convolutional Neural Network (CNN) model - Inception V3. The presented approach for classifying common office furniture objects (chairs, sofas and desks), contained in 3D point cloud scans, is tested and evaluated. The results show that the presented approach can classify common office furniture up to an acceptable degree of accuracy, and is suitable for quick and robust semantics approximation — based on RGB (red, green and blue color channel) cubemap images of the octree partitioned areas of the 3D point cloud scan. Additional methods for web-based 3D visualization, editing and annotation of point clouds are also discussed. Using the described approach, captured scans of indoor environments can be semantically enriched using object annotations derived from multiview classification results. Furthermore, the presented approach is suited for semantic enrichment of lower resolution indoor point clouds acquired using commodity mobile devices.
Semantic Enrichment of Indoor Point Clouds: An Overview of Progress towards Digital Twinning.Stojanovic, Vladeta; Trapp, Matthias; Richter, Rico; Hagedorn, Benjamin; Döllner, Jürgen (2019).
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Consistent Filtering of Videos and Dense Light-Fields Without Optic-Flow.Shekhar, Sumit; Semmo, Amir; Trapp, Matthias; Tursun, Okan Tarhan; Pasewaldt, Sebastian; Myszkowski, Karol; Döllner, Jürgen H. -J. Schulz, Teschner, M., Wimmer, M. (reds.) (2019).
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HerausgeberSchulz, H.-J. and Teschner, M. and Wimmer, M.
Advanced Visual Metaphors and Techniques for Software Maps.Limberger, Daniel; Scheibel, Willy; Döllner, Jürgen; Trapp, Matthias (2019).
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Web-based Visualization of Transportation Networks for Mobility Analytics.Schoedon, Alexander; Trapp, Matthias; Hollburg, Henning; Gerber, Daniel; Döllner, Jürgen (2019).
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Classification of Indoor Point Clouds Using Multiview.Stojanovic, Vladeta; Trapp, Matthias; Richter, Rico; Döllner, Jürgen (2019).
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Sensor Data Visualization for Indoor Point Clouds.Stojanovic, Vladeta; Trapp, Matthias; Hagedorn, Benjamin; Klimke, Jan; Richter, Rico; Döllner, Jürgen (2019).
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A Service-oriented Approach for Classifying 3D Points Clouds by Example of Office Furniture Classification.Stojanovic, Vladeta; Trapp, Matthias; Richter, Rico; Döllner, Jürgen (2018).
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Hierarchical Spatial Aggregation for Level-of-Detail Visualization of 3D Thematic Data.Vollmer, Jan Ole; Trapp, Matthias; Schumann, Heidrun; Döllner, Jürgen in ACM Transactions on Spatial Algorithms and Systems (2018). 4(3) 9:1--9:23.
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URNhttp://dx.doi.org/10.1145/3234506
AbstractThematic maps are a common tool to visualize semantic data with a spatial reference. Combining thematic data with a geometric representation of their natural reference frame aids the viewer’s ability in gaining an overview, as well as perceiving patterns with respect to location; however, as the amount of data for visualization continues to increase, problems such as information overload and visual clutter impede perception, requiring data aggregation and level-of-detail visualization techniques. While existing aggregation techniques for thematic data operate in a 2D reference frame (i.e., map), we present two aggregation techniques for 3D spatial and spatiotemporal data mapped onto virtual city models that hierarchically aggregate thematic data in real time during rendering to support on-the-fly and on-demand level-of-detail generation. An object-based technique performs aggregation based on scene-specific objects and their hierarchy to facilitate per-object analysis, while the scene-based technique aggregates data solely based on spatial locations, thus supporting visual analysis of data with arbitrary reference geometry. Both techniques can apply different aggregation functions (mean, minimum, and maximum) for ordinal, interval, and ratio-scaled data and can be easily extended with additional functions. Our implementation utilizes the programmable graphics pipeline and requires suitably encoded data, i.e., textures or vertex attributes. We demonstrate the application of both techniques using real-world datasets, including solar potential analyses and the propagation of pressure waves in a virtual city model.
MaeSTrO: A Mobile App for Style Transfer Orchestration using Neural Networks.Reimann, Max; Klingbeil, Mandy; Pasewaldt, Sebastian; Semmo, Amir; Trapp, Matthias; Döllner, Jürgen (2018). 9-16.
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URNhttp://dx.doi.org/10.1109/CW.2018.00016
AbstractMobile expressive rendering gained increasing popularity amongst users seeking casual creativity by image stylization and supports the development of mobile artists as a new user group. In particular, the neural style transfer has advanced as a core technology to emulate characteristics of manifold artistic styles and media without deep prior knowledge of photo processing or editing. However, when it comes to creative expression, the technology still faces inherent limitations in providing low-level controls for localized image stylization, e.g., with respect to image feature semantics or the user's ideas and interest. The goal of this work is to implement and enhance state-of-the-art neural style transfer techniques, providing a generalized user interface with interactive tools for local control that facilitate a creative editing process on mobile devices. At this, we first propose a problem characterization consisting of three goals that represent a trade-off between visual quality, run-time performance and ease of control. We then present MaeSTrO, a mobile app for orchestration of three neural style transfer techniques using iterative, multi-style generative and adaptive neural networks that can be locally controlled by on-screen painting metaphors to direct a semantics-based composition and perform location-based filtering. Based on first user tests, we conclude with insights, showing different levels of satisfaction for the implemented techniques and user interaction design, pointing out directions for future research.
Approaches for Local Artistic Control of Mobile Neural Style Transfer.Reimann, Max; Klingbeil, Mandy; Pasewaldt, Sebastian; Semmo, Amir; Döllner, Jürgen; Trapp, Matthias (2018).
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URNhttp://dx.doi.org/10.1145/3229147.3229188
AbstractThis work presents enhancements to state-of-the-art adaptive neural style transfer techniques, thereby providing a generalized user interface with creativity tool support for lower-level local control to facilitate the demanding interactive editing on mobile devices. The approaches are implemented in a mobile app that is designed for orchestration of three neural style transfer techniques using iterative, multi-style generative and adaptive neural networks that can be locally controlled by on-screen painting metaphors to perform location-based filtering and direct the composition. Based on first user tests, we conclude with insights, showing different levels of satisfaction for the implemented techniques and user interaction design, pointing out directions for future research.
Towards The Generation of Digital Twins for Facility Management Based on 3D Point Clouds.Stojanovic, Vladeta; Trapp, Matthias; Richter, Rico; Hagedorn, Benjamin; Döllner, Jürgen (2018).
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Service-based Processing and Provisioning of Image-Abstraction Techniques.Richter, Marvin; Söchting, Maximilian; Semmo, Amir; Döllner, Jürgen; Trapp, Matthias (2018).
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AbstractDigital images and image streams represent two major categories of media captured, delivered, and shared on the Web. Techniques for their analysis, classification, and processing are fundamental building blocks in today's digital media applications ranging from mobile image transformation apps to professional digital production suites. To efficiently process such digital media (1) independent of hardware requirements, (2) at different data complexity scales, (3) to yield high-quality results, poses several challenges for software frameworks and hardware systems, in particular for mobile devices. With respect to these aspects, using service-based architectures are a common approach to strive for. However, unlike geodata, there is currently no standard approach for service definition, implementation, and orchestration in the domain of digital images and videos. This paper presents an approach for service-based image processing and provisioning of processing techniques by the example of image-abstraction techniques. The generality and feasibility of the proposed system is demonstrated by different client applications that have been implemented for the Android Operation System, for Google's G-Suite Software-as-a-Service Infrastructure, as well as for Desktop systems. The performance of the system is discussed at the example of complex, resource-intensive image abstraction techniques, such as watercolor rendering.
Teaching Image-Processing Programming for Mobile Devices: A Software Development Perspective.Trapp, Matthias; Pasewaldt, Sebastian; Dürschmid, Tobias; Semmo, Amir; Döllner, Jürgen F. Post, Žára, J. (reds.) (2018).
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HerausgeberPost, Frits and Žára, Jirí
URNhttp://dx.doi.org/10.2312/eged.20181002
AbstractIn this paper we present a concept of a research course that teaches students in image processing as a building block of mobile applications. Our goal with this course is to teach theoretical foundations, practical skills in software development as well as scientific working principles to qualify graduates to start as fully-valued software developers or researchers. The course includes teaching and learning focused on the nature of small team research and development as encountered in the creative industries dealing with computer graphics, computer animation and game development. We discuss our curriculum design and issues in conducting undergraduate and graduate research that we have identified through four iterations of the course. Joint scientific demonstrations and publications of the students and their supervisors as well as quantitative and qualitative evaluation by students underline the success of the proposed concept. In particular, we observed that developing using a common software framework helps the students to jump start their course projects, while industry software processes such as branching coupled with a three-tier breakdown of project features helps them to structure and assess their progress.
Service-Oriented Processing and Analysis of Massive Point Clouds in Geoinformation Management.Discher, Sören; Richter, Rico; Trapp, Matthias; Döllner, Jürgen in Service Oriented Mapping: Changing Paradigm in Map Production and Geoinformation Management, J. Döllner, Jobst, M., Schmitz, P. (reds.) (2018).
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HerausgeberDöllner, Jürgen and Jobst, Markus and Schmitz, Peter
Towards Architectural Styles for Android App Software Product Lines.Dürschmid, Tobias; Trapp, Matthias; Döllner, Jürgen (2017).
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ProsumerFX: Mobile Design of Image Stylization Components.Dürschmid, Tobias; Söchting, Maximilian; Semmo, Amir; Trapp, Matthias; Döllner, Jürgen (2017).
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URNhttp://dx.doi.org/10.1145/3132787.3139208
AbstractWith the continuous advances of mobile graphics hardware, high-quality image stylization—e.g., based on image filtering, stroke-based rendering, and neural style transfer—is becoming feasible and increasingly used in casual creativity apps. The creative expression facilitated by these mobile apps, however, is typically limited with respect to the usage and application of pre-defined visual styles, which ultimately do not include their design and composition—an inherent requirement of prosumers. We present ProsumerFX, a GPU-based app that enables to interactively design parameterizable image stylization components on-device by reusing building blocks of image processing effects and pipelines. Furthermore, the presentation of the effects can be customized by modifying the icons, names, and order of parameters and presets. Thereby, the customized visual styles are defined as platform-independent effects and can be shared with other users via a web-based platform and database. Together with the presented mobile app, this system approach supports collaborative works for designing visual styles, including their rapid prototyping, A/B testing, publishing, and distribution. Thus, it satisfies the needs for creative expression of both professionals as well as the general public.
Pictory: Combining Neural Style Transfer and Image Filtering.Semmo, Amir; Trapp, Matthias; Döllner, Jürgen; Klingbeil, Mandy (2017). 5:1--5:2.
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URNhttp://dx.doi.org/10.1145/3098900.3098906
AbstractThis work presents Pictory, a mobile app that empowers users to transform photos into artistic renditions by using a combination of neural style transfer with user-controlled state-of-the-art nonlinear image filtering. The combined approach features merits of both artistic rendering paradigms: deep convolutional neural networks can be used to transfer style characteristics at a global scale, while image filtering is able to simulate phenomena of artistic media at a local scale. Thereby, the proposed app implements an interactive two-stage process: first, style presets based on pre-trained feed-forward neural networks are applied using GPU-accelerated compute shaders to obtain initial results. Second, the intermediate output is stylized via oil paint, watercolor, or toon filtering to inject characteristics of traditional painting media such as pigment dispersion (watercolor) as well as soft color blendings (oil paint), and to filter artifacts such as fine-scale noise. Finally, on-screen painting facilitates pixel-precise creative control over the filtering stage, e. g., to vary the brush and color transfer, while joint bilateral upsampling enables outputs at full image resolution suited for printing on real canvas.
Comparative Visualization of BIM Geometry and Corresponding Point Clouds.Stojanovic, Vladeta; Richter, Rico; Döllner, Jürgen; Trapp, Matthias in International Journal of Sustainable Development and Planning (2017). 13(1)
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URNhttp://dx.doi.org/10.2495/SDP-V13-N1-12-23
Mixed-Projection Treemaps: A Novel Approach Mixing 2D and 2.5D Treemaps.Limberger, Daniel; Scheibel, Willy; Trapp, Matthias; Döllner, Jürgen (2017).
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Attributed Vertex Clouds.Scheibel, Willy; Buschmann, Stefan; Trapp, Matthias; Döllner, Jürgen in GPU Zen, W. Engel, Oat, C. (reds.) (2017). (8 ed)
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HerausgeberEngel, Wolfgang and Oat, Christopher
AbstractIn todays computer graphics applications, large 3D scenes are rendered which consist of polygonal geometries such as triangle meshes. Using state- of-the-art techniques, this geometry is often represented on the GPU using vertex and index buffers, as well as additional auxiliary data such as tex- tures or uniform buffers. For polygonal meshes of arbitrary complexity, the described approach is indispensable. However, there are several types of simpler geometries (e.g., cuboids, spheres, tubes, or splats) that can be generated procedurally. We present an efficient data representation and render- ing concept for such geometries, denoted as attributed vertex clouds (AVCs). Using this approach, geometry is generated on the GPU during execution of the programmable rendering pipeline. Each vertex is used as the argument for a function that procedurally generates the target geometry. This function is called a transfer function, and it is implemented using shader programs and therefore executed as part of the rendering process. This approach allows for compact geometry representation and results in reduced memory footprints in comparison to traditional representations. By shifting geometry generation to the GPU, the resulting volatile geometry can be controlled flexibly, i.e., its position, parameteri- zation, and even the type of geometry can be modified without requiring suggests improved rendering times and reduced memory transmission through the rendering pipeline.
Mixed-Projection Treemaps: A Novel Approach Mixing 2D and 2.5D Treemaps.Limberger, Daniel; Scheibel, Willy; Trapp, Matthias; Döllner, Jürgen (2017).
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Abstract2D treemaps are a space-filling visualization technique that facilitate exploration of non-spatial, attributed, tree-structured data using the visual variables size and color. In extension thereto, 2.5D treemaps introduce height for additional information display. This extension entails challenges such as increased rendering effort, occlusion, or the need for navigation techniques that counterbalance the advantages of 2D treemaps to a certain degree. This paper presents a novel technique for combining 2D and 2.5D treemaps using multi-perspective views to leverage the advantages of both treemap types. It enables a new form of overview+detail visualization for complex treemaps and contributes new concepts for real-time rendering of and interaction with mixed-projection treemaps. The technique operates by tilting up inner nodes using affine transformations and animated state transitions. The mixed use of orthogonal and perspective projections is discussed and application examples that facilitate exploration of multi-variate data and benefit from the reduced interaction overhead are demonstrated.
Interactive Image Filtering with Multiple Levels-of-Control on Mobile Devices.Semmo, Amir; Dürschmid, Tobias; Trapp, Matthias; Klingbeil, Mandy; Döllner, Jürgen; Pasewaldt, Sebastian (2016).
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URNhttp://dx.doi.org/10.1145/2999508.2999521
AbstractWith the continuous development of mobile graphics hardware, interactive high-quality image stylization based on nonlinear filtering is becoming feasible and increasingly used in casual creativity apps. However, these apps often only serve high-level controls to parameterize image filters and generally lack support for low-level (artistic) control, thus automating art creation rather than assisting it. This work presents a GPU-based framework that enables to parameterize image filters at three levels of control: (1) presets followed by (2) global parameter adjustments can be interactively refined by (3) complementary on-screen painting that operates within the filters' parameter spaces for local adjustments. The framework provides a modular XML-based effect scheme to effectively build complex image processing chains-using these interactive filters as building blocks-that can be efficiently processed on mobile devices. Thereby, global and local parameterizations are directed with higher-level algorithmic support to ease the interactive editing process, which is demonstrated by state-of-the-art stylization effects, such as oil paint filtering and watercolor rendering.
Interactive Revision Exploration using Small Multiples of Software Maps.Scheibel, Willy; Trapp, Matthias; Döllner, Jürgen in IVAPP 2016 (2016). 131-138.
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AbstractTo explore and to compare different revisions of complex software systems is a challenging task as it requires to constantly switch between different revisions and the corresponding information visualization. This paper proposes to combine the concept of small multiples and focus+context techniques for software maps to facilitate the comparison of multiple software map themes and revisions simultaneously on a single screen. This approach reduces the amount of switches and helps to preserve the mental map of the user. Given a software project the small multiples are based on a common dataset but are specialized by specific revisions and themes. The small multiples are arranged in a matrix where rows and columns represents different themes and revisions, respectively. To ensure scalability of the visualization technique we also discuss two rendering pipelines to ensure interactive frame-rates. The capabilities of the proposed visualization technique are demonstrated in a collaborative exploration setting using a high-resolution, multi-touch display.
Interactive Oil Paint Filtering On Mobile Devices.Semmo, Amir; Trapp, Matthias; Pasewaldt, Sebastian; Döllner, Jürgen (2016).
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URNhttp://dx.doi.org/10.2312/exp.20161255
AbstractImage stylization enjoys a growing popularity on mobile devices to foster casual creativity. However, the implementation and provision of high-quality image filters for artistic rendering is still faced by the inherent limitations of mobile graphics hardware such as computing power and memory resources. This work presents a mobile implementation of a filter that transforms images into an oil paint look, thereby highlighting concepts and techniques on how to perform multi-stage nonlinear image filtering on mobile devices. The proposed implementation is based on OpenGL ES and the OpenGL ES shading language, and supports on-screen painting to interactively adjust the appearance in local image regions, e.g., to vary the level of abstraction, brush, and stroke direction. Evaluations of the implementation indicate interactive performance and results that are of similar aesthetic quality than its original desktop variant.
Interactive Multi-scale Oil Paint Filtering on Mobile Devices.Semmo, Amir; Trapp, Matthias; Dürschmid, Tobias; Döllner, Jürgen; Pasewaldt, Sebastian (2016).
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URNhttp://dx.doi.org/10.1145/2945078.2945120
AbstractThis work presents an interactive mobile implementation of a filter that transforms images into an oil paint look. At this, a multi-scale approach that processes image pyramids is introduced that uses flow-based joint bilateral upsampling to achieve deliberate levels of abstraction at multiple scales and interactive frame rates. The approach facilitates the implementation of interactive tools that adjust the appearance of filtering effects at run-time, which is demonstrated by an on-screen painting interface for per-pixel parameterization that fosters the casual creativity of non-artists.
Interactive GPU-based Image Deformation for Mobile Devices.Vollmer, Jan Ole; Trapp, Matthias; Döllner, Jürgen (2016).
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URNhttp://dx.doi.org/10.2312/cgvc.20161303
AbstractInteractive image deformation is an important feature of modern image processing pipelines. It is often used to create caricatures and animation for input images, especially photos. State-of-the-art image deformation techniques are based on transforming vertices of a mesh, which is textured by the input image, using affine transformations such as translation, and scaling. However, the resulting visual quality of the output image depends on the geometric resolution of the mesh. Performing these transformations on the CPU often further inhibits performance and quality. This is especially problematic on mobile devices where the limited computational power reduces the maximum achievable quality. To overcome these issue, we propose the concept of an intermediate deformation buffer that stores deformation information at a resolution independent of the mesh resolution. This allows the combination of a high-resolution buffer with a low-resolution mesh for interactive preview, as well as a high-resolution mesh to export the final image. Further, we present a fully GPU-based implementation of this concept, taking advantage of modern OpenGL ES features, such as compute shaders.
Evaluation of Sketchiness as a Visual Variable for 2.5D Treemaps.Limberger, Daniel; Fiedler, Carolin; Hahn, Sebastian; Trapp, Matthias; Döllner, Jürgen (2016).
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AbstractInteractive 2.5D treemaps serve as an effective tool for the visualization of attributed hierarchies, enabling exploration of non-spatial, multi-variate, hierarchical data. In this paper the suitability of sketchiness as a visual variable, e.g., for uncertainty, is evaluated. Therefore, a design space for sketchy rendering in 2.5D and integration details for real-time applications are presented. The results of three user studies indicate, that sketchiness is a promising candidate for a visual variable that can be used independently and in addition to others, e.g., color and height. © The Authors 2016. This is the authors' version of the work. It is posted here for your personal use. Not for redistribution. The definitive version will be published in Proceedings of the 20th International Conference on Information Visualization (IV'16).
Interactive Web-based Visualization for Accessibility Mapping of Transportation Networks.Schoedon, Alexander; Trapp, Matthias; Hollburg, Henning; Döllner, Jürgen (2016).
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AbstractAccessibility is a fundamental aspect in transportation, routing, and spare-time activity planning concerning traveling in modern cities. In this context, interactive web-based accessibility-map visualization techniques and systems are important tools for provisioning, exploration, analysis, and assessment of multi-modal and location-based travel time data and routing information. To enable their effective application, such interactive visualization techniques demands for flexible mappings with respect to user-adjustable parameters such as maximum travel times, the types of transportation used, or used color schemes. However, traditional approaches for web-based visualization of accessibility-maps do not allow this degree of parametrization without significant latencies introduced by required data processing and transmission between the routing server and the visualization client. This paper presents a novel web-based visualization technique that allows for efficient client-side mapping and rendering of accessibility data onto transportation networks using WebGL and the OpenGL transmission format. A performance evaluation and comparison shows the superior performance of the approach over alternative implementations.
Animated visualization of spatial-temporal trajectory data for air-traffic analysis.Buschmann, Stefan; Trapp, Matthias; Döllner, Jürgen in The Visual Computer (2015). 32(3) 371-381.
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AbstractWith increasing numbers of flights worldwide and a continuing rise in airport traffic, air-traffic management is faced with a number of challenges. These include monitoring, reporting, planning, and problem analysis of past and current air traffic, e.g., to identify hotspots, minimize delays, or to optimize sector assignments to air-traffic controllers. To cope with these challenges, cyber worlds can be used for interactive visual analysis and analytical reasoning based on aircraft trajectory data. However, with growing data size and complexity, visualization requires high computational efficiency to process that data within real-time constraints. This paper presents a technique for real-time animated visualization of massive trajectory data. It enables (1) interactive spatio-temporal filtering, (2) generic mapping of trajectory attributes to geometric representations and appearance, and (3) real-time rendering within 3D virtual environments such as virtual 3D airport or 3D city models. Different visualization metaphors can be efficiently built upon this technique such as temporal focus+context, density maps, or overview+detail methods. As a general-purpose visualization technique, it can be applied to general 3D and 3+1D trajectory data, e.g., traffic movement data, geo-referenced networks, or spatio-temporal data, and it supports related visual analytics and data mining tasks within cyber worlds.
VideoMR: A Map and Reduce Framework for Real-time Video Processing.Meier, Benjamin-Heinz; Trapp, Matthias; Döllner, Jürgen (2015).
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AbstractThis paper presents VideoMR: a novel map and reduce framework for real-time video processing on graphic processing units (GPUs). Using the advantages of implicit parallelism and bounded memory allocation, our approach enables developers to focus on implementing video operations without taking care of GPU memory handling or the details of code parallelization. Therefore, a new concept for map and reduce is introduced, redefining both operations to fit to the specific requirements of video processing. A prototypical implementation using OpenGL facilitates various operating platforms, including mobile development, and will be widely interoperable with other state-of-the-art video processing frameworks.
Natural Phenomena as Metaphors for Visualization of Trend Data in Interactive Software Maps.Würfel, Hannes; Trapp, Matthias; Limberger, Daniel; Döllner, Jürgen (2015).
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URNhttp://dx.doi.org/10.2312/cgvc.20151246
AbstractSoftware maps are a commonly used tool for code quality monitoring in software-development projects and decision making processes. While providing an important visualization technique for the hierarchical system structure of a single software revision, they lack capabilities with respect to the visualization of changes over multiple revisions. This paper presents a novel technique for visualizing the evolution of the software system structure based on software metric trends. These trend maps extend software maps by using real-time rendering techniques for natural phenomena yielding additional visual variables that can be effectively used for the communication of changes. Therefore, trend data is automatically computed by hierarchically aggregating software metrics. We demonstrate and discuss the presented technique using two real world data sets of complex software systems.
Geometry Batching Using Texture-Arrays.Trapp, Matthias; Döllner, Jürgen (2015). 239-246.
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AbstractHigh-quality rendering of 3D virtual environments typically depends on high-quality 3D models with significant geometric complexity and texture data. One major bottleneck for real-time image-synthesis represents the number of state changes, which a specific rendering API has to perform. To improve performance, batching can be used to group and sort geometric primitives into batches to reduce the number of required state changes, whereas the size of the batches determines the number of required draw-calls, and therefore, is critical for rendering performance. For example, in the case of texture atlases, which provide an approach for efficient texture management, the batch size is limited by the efficiency of the texture-packing algorithm and the texture resolution itself. This paper presents a pre-processing approach and rendering technique that overcomes these limitations by further grouping textures or texture atlases and thus enables the creation of larger geometry batches. It is based on texture arrays in combination with an additional indexing schema that is evaluated at run-time using shader programs. This type of texture management is especially suitable for real-time rendering of large-scale texture-rich 3D virtual environments, such as virtual city and landscape models.
Real-Time Visualization of Massive Movement Data in Digital Landscapes.Buschmann, Stefan; Trapp, Matthias; Döllner, Jürgen (2015). 213-220.
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AbstractDue to continuing advances in sensor technology and increasing availability of digital infrastructure that allows for acquisition, transfer, and storage of big data sets, large amounts of movement data (e.g., road, naval, or air-traffic) become available. In the near future, movement data such as traffic data may even be available in real-time. In a growing number of application fields (e.g., landscape planning and design, urban development, and infrastructure planning), movement data enables new analysis and simulation applications. In this paper, we present an interactive technique for visualizing massive 3D movement trajectories. It is based on mapping massive movement data to graphics primitives and their visual variables in real-time, supporting a number of visualization schemes such as sphere, line, or tube-based trajectories, including animations of direction and speed. This generic technique enhances the functionality of VR and interactive 3D systems using virtual environments such as digital landscape models, city models, or virtual globes by adding support for this important category of spatio-temporal data.
Cartography-Oriented Design of 3D Geospatial Information Visualization - Overview and Techniques.Semmo, Amir; Trapp, Matthias; Jobst, Markus; Döllner, Jürgen in The Cartographic Journal (2015). 52(2) 95--106.
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URNhttp://dx.doi.org/10.1080/00087041.2015.1119462
AbstractIn economy, society and personal life map-based, interactive geospatial visualization becomes a natural element of a growing number of applications and systems. The visualization of 3D geospatial information, however, raises the question how to represent the information in an effective way. Considerable research has been done in technology-driven directions in the fields of cartography and computer graphics (e.g., design principles, visualization techniques). Here, non-photorealistic rendering represents a promising visualization category–situated between both fields–that offers a large number of degrees for the cartography-oriented visual design of complex 2D and 3D geospatial information for a given application context. Still today, however, specifications and techniques for mapping cartographic design principles to the state-of-the-art rendering pipeline of 3D computer graphics remain to be explored. This paper revisits cartographic design principles for 3D geospatial visualization and introduces an extended 3D semiotic model that complies with the general, interactive visualization pipeline. Based on this model, we propose non-photorealistic rendering techniques to interactively synthesize cartographic renditions of basic feature types, such as terrain, water, and buildings. In particular, it includes a novel iconification concept to seamlessly interpolate between photorealistic and cartographic representations of 3D landmarks. Our work concludes with a discussion of open challenges in this field of research, including topics such as user interaction and evaluation.
ThreadCity: Combined Visualization of Structure and Activity for the Exploration of Multi-threaded Software Systems.Hahn, Sebastian; Trapp, Matthias; Wuttke, Nikolai; Döllner, Jürgen (2015).
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AbstractThis paper presents a novel visualization technique for the interactive exploration of multi-threaded software systems. It combines the visualization of static system structure based on the EvoStreets approach with an additional traffic metaphor to communicate the runtime characteristics of multiple threads simultaneously. To improve visual scalability with respect to the visualization of complex software systems, we further present an effective level-of-detail visualization based on hierarchical aggregation of system components by taking viewing parameters into account. We demonstrate our technique by means of a prototypical implementation and compare our result with existing visualization techniques. © The Authors 2015. This is the authors' version of the work. It is posted here for your personal use. Not for redistribution. The definitive version will be published in Proceedings of the 19th International Conference on Information Visualization (IV'15).
Interactive Rendering and Stylization of Transportation Networks Using Distance Fields.Trapp, Matthias; Semmo, Amir; Döllner, Jürgen (2015). 207-219.
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AbstractTransportation networks, such as streets, railroads or metro systems, constitute primary elements in cartography for reckoning and navigation. In recent years, they have become an increasingly important part of 3D virtual environments for the interactive analysis and communication of complex hierarchical information, for example in routing, logistics optimization, and disaster management. A variety of rendering techniques have been proposed that deal with integrating transportation networks within these environments, but have so far neglected the many challenges of an interactive design process to adapt their spatial and thematic granularity (i.e., level-of-detail and level-of-abstraction) according to a user's context. This paper presents an efficient real-time rendering technique for the view-dependent rendering of geometrically complex transportation networks within 3D virtual environments. Our technique is based on distance fields using deferred texturing that shifts the design process to the shading stage for real-time stylization. We demonstrate and discuss our approach by means of street networks using cartographic design principles for context-aware stylization, including view-dependent scaling for clutter reduction, contour-lining to provide figure-ground, handling of street crossings via shading-based blending, and task-dependent colorization. Finally, we present potential usage scenarios and applications together with a performance evaluation of our implementation.
Multi-Perspective 3D Panoramas.Pasewaldt, Sebastian; Semmo, Amir; Trapp, Matthias; Döllner, Jürgen in International Journal of Geographical Information Science (IJGIS) (2014). 28(10) 2030-2051.
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URNhttp://dx.doi.org/10.1080/13658816.2014.922686
AbstractThis article presents multi-perspective 3D panoramas that focus on visualizing 3D geovirtual environments (3D GeoVEs) for navigation and exploration tasks. Their key element, a multi-perspective view, seamlessly combines what is seen from multiple viewpoints into a single image. This approach facilitates thepresentation of information for virtual 3D city and landscape models, particularly by reducing occlusions, increasing screen-space utilization, and providing additional context within a single image. We complement multi-perspective views with cartographic visualization techniques to stylize features according to their semantics and highlight important or prioritized information. When combined, both techniques constitute the core implementation of interactive, multi-perspective 3D panoramas. They offer a large number of effective means for visual communication of 3D spatial information, a high degree of customization with respect to cartographic design, and manifold applications in different domains. We discuss design decisions of 3D panoramas for the exploration of and navigation in 3D GeoVEs. We also discuss a preliminary user study that indicates that 3D panoramas are a promising approach for navigation systems using 3D GeoVEs.
Web-based and Mobile Provisioning of Virtual 3D Reconstructions.Klimke, Jan; Hagedorn, Benjamin; Trapp, Matthias; Döllner, Jürgen R. Franken-Wendelstorf, Lindinger, E., Sieck, J. (reds.) (2014). 17--28.
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HerausgeberFranken-Wendelstorf, R. and Lindinger, E. and Sieck, J.
AbstractCommunication of cultural heritage by means of digital information systems has been gaining more and more importance over recent years. Interactive virtual 3D applications enable users to explore 3D virtual reconstructions in real-time, to directly interact with the contained digital cultural heritage artifacts, and to obtain insights into this data. Nevertheless, these artifacts are usually very detailed and complex 3D models that are hard to handle for end-user systems. This paper presents the concept and a prototypical implementation of an image-based, web-based approach for the communication of digital cultural heritage and its provisioning for the Web and mobile devices by the example of the project Colonia3D – a high-detail, virtual reconstruction and high-detail 3D city model of Roman Cologne. Through this web-based and mobile provisioning, complex digital reconstructions can be used, e.g., on-site to match local findings and reconstructions.
Real-Time Animated Visualization of Massive Air-Traffic Trajectories.Buschmann, Stefan; Trapp, Matthias; Döllner, Jürgen (2014). 172-181.
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URNhttp://dx.doi.org/10.1109/CW.2014.32
AbstractWith increasing numbers of flights world-wide and a continuing rise in airport traffic, air-traffic management is faced with a number of challenges. These include monitoring, reporting, planning, and problem analysis of past and current air traffic, e.g., to identify hotspots, minimize delays, or to optimize sector assignments to air-traffic controllers. Interactive and dynamic 3D visualization and visual analysis of massive aircraft trajectories, i.e., analytical reasoning enabled by interactive cyber worlds, can be used to approach these challenges. To facilitate this kind of analysis, especially in the context of real-time data, interactive tools for filtering, mapping, and rendering are required. In particular, the mapping process should be configurable at run-time and support both static mappings and animations to allow users to effectively explore and realize movement dynamics. However, with growing data size and complexity, these stages of the visualization pipeline require computational efficient implementations to be capable of processing within real-time constraints. This paper presents an approach for real-time animated visualization of massive air-traffic data, that implements all stages of the visualization pipeline based on GPU techniques for efficient processing. It enables (1) interactive spatio-temporal filtering, (2) generic mapping of trajectory attributes to geometric representations and appearances, as well as (3) real-time rendering within 3D virtual environments, such as virtual 3D airport and city models. Based on this pipeline, different visualization metaphors (e.g., temporal focus+context, density maps, and overview+detail visualization) are implemented and discussed. The presented concepts and implementation can be generally used as visual analytics and data mining techniques in cyber worlds, e.g., to visualize movement data, geo-referenced networks, or other spatio-temporal data.
Hardware-Accelerated Attribute Mapping for Interactive Visualization of Complex 3D Trajectories.Buschmann, Stefan; Trapp, Matthias; Lühne, Patrick; Döllner, Jürgen (2014). 355-363.
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AbstractThe visualization of 3D trajectories of moving objects and related attributes in 3D virtual environments represents a fundamental functionality in various visualization domains. Interactive rendering and visual analytics of such attributed trajectories involves both conceptual questions as well as technical challenges. Specifically, the mapping of trajectory attributes to rendering primitives and appearance represents a challenging task in the case of large data sets of high geometric complexity. There are various visualization approaches and rendering techniques considering specific aspects of these mappings to facilitate visualization and analysis of this kind of data. To solve the underlying general mapping problem efficiently, we developed an approach that uses and combines diverse types of visualizations, rather than being tailored to a specific use case. This paper describes an interactive rendering system for the visualization of 3D trajectories that enables the combinations of different mappings as well as their dynamic configuration at runtime. A fully hardware-accelerated implementation enables the processing of large sets of attributed 3D trajectories in real-time.
2D and 3D Presentation of Spatial Data: A Systematic Review.Dübel, Steve; Röhlig, Martin; Schumann, Heidrun; Trapp, Matthias (2014).
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AbstractThe question whether to use 2D or 3D for data visualization is generally difficult to decide. Two-dimensional and three-dimensional visualization techniques exhibit different advantages and disadvantages related to various perceptual and technical aspects such as occlusion, clutter, distortion, or scalability. To facilitate problem understanding and comparison of existing visualization techniques with regard to these aspects, this report introduces a systematization based on presentation characteristics. It enables a categorization with respect to combinations of static 2D and 3D presentations of attributes and their spatial reference. Further, it complements ex-isting systematizations of data in an effort to formalize a common terminology and theoretical framework for this problem domain. We demonstrate our approach by reviewing different visualization techniques of spatial data according to the presented systematization.
Interactive Rendering Techniques for Focus+Context Visualization of 3D Geovirtual Environments. Technical Report (PhD dissertation), Trapp, Matthias PhD thesis, Hasso-Plattner-Institut für Softwaresystemtechnik GmbH, Prof.-Dr.-Helmert-Str. 2-3, D-14482 Potsdam. (2013).
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AbstractThis thesis introduces a collection of new real-time rendering techniques and applications for focus+context visualization of interactive 3D geovirtual environments such as virtual 3D city and landscape models. These environments are generally characterized by a large number of objects and are of high complexity with respect to geometry and textures. For these reasons, their interactive 3D rendering represents a major challenge. Their 3D depiction implies a number of weaknesses such as occlusions, cluttered image contents, and partial screen-space usage. To overcome these limitations and, thus, to facilitate the effective communication of geo-information, principles of focus+context visualization can be used for the design of real-time 3D rendering techniques for 3D geovirtual environments (see Figure). In general, detailed views of a 3D geovirtual environment are combined seamlessly with abstracted views of the context within a single image. To perform the real-time image synthesis required for interactive visualization, dedicated parallel processors (GPUs) for rasterization of computer graphics primitives are used. For this purpose, the design and implementation of appropriate data structures and rendering pipelines are necessary. The contribution of this work comprises the following five real-time rendering methods: The rendering technique for 3D generalization lenses enables the combination of different 3D city geometries (e.g., generalized versions of a 3D city model) in an single image in real time. The method is based on a generalized and fragment-precise clipping approach, which uses a compressible, raster-based data structure. It enables the combination of detailed views in the focus area with the representation of abstracted variants in the context area. The rendering technique for the interactive visualization of dynamic raster data in 3D geovirtual environments facilitates the rendering of 2D surface lenses. It enables a flexible combination of different raster layers (e.g., aerial images or videos) using projective texturing for decoupling image and geometry data. Thus, various overlapping and nested 2D surface lenses of different contents can be visualized interactively. The interactive rendering technique for image-based deformation of 3D geovirtual environments enables the real-time image synthesis of non-planar projections, such as cylindrical and spherical projections, as well as multi-focal 3D fisheye-lenses and the combination of planar and non-planar projections. The rendering technique for view-dependent multi-perspective views of 3D geovirtual environments, based on the application of global deformations to the 3D scene geometry, can be used for synthesizing interactive panorama maps to combine detailed views close to the camera (focus) with abstract views in the background (context). This approach reduces occlusions, increases the usage the available screen space, and reduces the overload of image contents. The object-based and image-based rendering techniques for highlighting objects and focus areas inside and outside the view frustum facilitate preattentive perception. The concepts and implementations of interactive image synthesis for focus+context visualization and their selected applications enable a more effective communication of spatial information, and provide building blocks for design and development of new applications and systems in the field of 3D geovirtual environments.
Real-Time Rendering of Water Surfaces with Cartography-Oriented Design.Semmo, Amir; Kyprianidis, Jan Eric; Trapp, Matthias; Döllner, Jürgen in Proceedings International Symposium on Computational Aesthetics in Graphics, Visualization, and Imaging (CAe) (2013). 5--14.
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URNhttp://dx.doi.org/10.1145/2487276.2487277
AbstractMore than 70% of the Earth's surface is covered by oceans, seas, and lakes, making water surfaces one of the primary elements in geospatial visualization. Traditional approaches in computer graphics simulate and animate water surfaces in the most realistic ways. However, to improve orientation, navigation, and analysis tasks within 3D virtual environments, these surfaces need to be carefully designed to enhance shape perception and land-water distinction. We present an interactive system that renders water surfaces with cartography-oriented design using the conventions of mapmakers. Our approach is based on the observation that hand-drawn maps utilize and align texture features to shorelines with non-linear distance to improve figure-ground perception and express motion. To obtain local orientation and principal curvature directions, first, our system computes distance and feature-aligned distance maps. Given these maps, waterlining, water stippling, contour-hatching, and labeling are applied in real-time with spatial and temporal coherence. The presented methods can be useful for map exploration, landscaping, urban planning, and disaster management, which is demonstrated by various real-world virtual 3D city and landscape models. © ACM, 2013. This is the authors' version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in Proceedings of the International Symposium on Computational Aesthetics in Graphics, Visualization, and Imaging (CAe'13). http://dx.doi.org/10.1145/2487276.2487277.
Evaluating the Perceptual Impact of Rendering Techniques on Thematic Color Mappings in 3D Virtual Environments.Engel, Juri; Semmo, Amir; Trapp, Matthias; Döllner, Jürgen J. F. Michael Bronstein, Hormann, K. (reds.) (2013). 25-32.
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HerausgeberMichael Bronstein, Jean Favre and Hormann, Kai
URNhttp://dx.doi.org/10.2312/PE.VMV.VMV13.025-032
AbstractUsing colors for thematic mapping is a fundamental approach in visualization, and has become essential for 3D virtual environments to effectively communicate multidimensional, thematic information. Preserving depth cues within these environments to emphasize spatial relations between geospatial features remains an important issue.A variety of rendering techniques have been developed to preserve depth cues in 3D information visualization, including shading, global illumination, and image stylization. However, these techniques alter color values, which may lead to ambiguity in a color mapping and loss of information. Depending on the applied rendering techniques and color mapping, this loss should be reduced while still preserving depth cues when communicating thematic information. This paper presents the results of a quantitative and qualitative user study that evaluates the impact of rendering techniques on information and spatial perception when using visualization of thematic data in 3D virtual environments. We report the results of this study with respect to four perception-related tasks, showing significant differences in error rate and task completion time for different rendering techniques and color mappings.
Multi-Perspective Detail+Overview Visualization for 3D Building Exploration.Pasewaldt, Sebastian; Trapp, Matthias; Döllner, Jürgen S. Czanner, Tang, W. (reds.) (2013). 57--64.
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HerausgeberCzanner, Silvester and Tang, Wen
AbstractThis paper presents a multi-perspective rendering technique that enables detail+overview visualization and interactive exploration of virtual 3D building model. Virtual 3D building models, as main elements of virtual 3D city models, are used in a growing number of application domains, such as geoanalysis, disaster management and architectural planning. Visualization systems for such building models often rely on perspective or orthogonal projections using a single viewpoint. Therefore, the exploration of a complete model requires a user to change the viewpoint multiple times and to memorize the content of each view to obtain a comprehensive mental model. Since this is usually a time-consuming task, which implies context switching, current visualization systems use multiple viewports to simultaneously depict an object from different perspectives. Our approach extends the idea of multiple viewports by combining two linked views for the interactive exploration of virtual 3D buildings model and their facades. In contrast to traditional approaches, we automatically generate a multi-perspective view that simultaneously depicts all facades of the building in one overview image. This facilitates the process of obtaining overviews and supports fast and direct navigation to various points-of-interest. We describe the concept and implementations of our Multiple-Center-of-Projection camera model for real-time multi-perspective image synthesis. Further, we provide insights into different interaction techniques for linked multi-perspective views and outline approaches of future work.
Interactive Projective Texturing for Non-Photorealistic Shading of Technical 3D Models.Lux, Roland; Trapp, Matthias; Semmo, Amir; Döllner, Jürgen S. Czanner, Tang, W. (reds.) (2013). 101--108.
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HerausgeberCzanner, Silvester and Tang, Wen
AbstractThis paper presents a novel interactive rendering technique for creating and editing shadings for man-made objects in technical 3D visualizations. In contrast to shading approaches that use intensities computed based on surface normals (e.g., Phong, Gooch, Toon shading), the presented approach uses one-dimensional gradient textures, which can be parametrized and interactively manipulated based on per-object bounding volume approximations. The fully hardware-accelerated rendering technique is based on projective texture mapping and customizable intensity transfer functions. A provided performance evaluation shows comparable results to traditional normal-based shading approaches. The work also introduce simple direct-manipulation metaphors that enables interactive user control of the gradient texture alignment and intensity transfer functions.
Interactive Rendering of Complex 3D-Treemaps.Trapp, Matthias; Hahn, Sebastian; Döllner, Jürgen S. Coquillart, Andujar, C., Laramee, R. S., Kerren, A., Braz, J. (reds.) (2013). 165-175.
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HerausgeberCoquillart, Sabine and Andujar, Carlos and Laramee, Robert S. and Kerren, Andreas and Braz, José
Abstract3D-Treemaps are an important visualization technique for hierarchical views. In contrast to 2D-Treemaps, height can be used to map one additional attribute of the data items. Using the Treemap technique in combination with large datasets (more than 500k) a fast rendering and interaction techniques that are beyond collapsing/uncollapsing nodes is still one of the main challenges. This paper presents a novel rendering technique that enables the image synthesis of geometrical complex 3D-Treemaps in real-time. The fully hardware accelerated approach is based on shape generation using geometry shaders. This approach offers increased rendering performance and low update latency compared to existing techniques and through it enables new real-time interaction techniques to large datasets.
2.5D Clip-Surfaces for Technical Visualization.Trapp, Matthias; Döllner, Jürgen in Journal of WSCG, (V. Skala, red.) (2013). 21(1) 89-96.
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HerausgeberSkala, Václav
AbstractThe concept of clipping planes is well known in computer graphics and can be used to create cut-away views. But clipping against just analytical defined planes is not always suitable for communicating every aspect of such visualization. For example, in hand-drawn technical illustrations, artists tend to communicate the difference between a cut and a model feature by using non-regular, sketchy cut lines instead of straight ones. To enable this functionality in computer graphics, this paper presents a technique for applying 2.5D clip-surfaces in real-time. Therefore, the clip plane equation is extended with an additional offset map, which can be represented by a texture map that contains height values. Clipping is then performed by varying the clip plane equation with respect to such an offset map. Further, a capping technique is proposed that enables the rendering of caps onto the clipped area to convey the impression of solid material. It avoids a re-meshing of a solid polygonal mesh after clipping is performed. Our approach is pixel precise, applicable in real-time, and takes fully advantage of graphics accelerators.
An Immersive Visualization System for Virtual 3D City Models.Engel, Juri; Pasewaldt, Sebastian; Trapp, Matthias; Döllner, Jürgen (2012).
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AbstractVirtual 3D city models are essential visualization tools for effective communication of complex urban spatial information. Immersive visualization of virtual 3D city models offers an intuitive access to and an effective way of realization of urban spatial information, enabling new collaborative applications and decision-support systems. This paper discusses techniques for and usage of fully immersive environments for visualizing virtual 3D city models by advanced 3D rendering techniques. Fully immersive environments imply a number of specific requirements for both hardware and software, which are discussed in detail. Further, we identify and outline conceptual and technical challenges as well as possible solution approaches by visualization system prototypes for large-scale, fully immersive environments. We evaluate the presented concepts using two application examples and discuss the results.
Colonia 3D - Communication of Virtual 3D Reconstructions in Public Spaces.Trapp, Matthias; Semmo, Amir; Pokorski, Rafael; Herrmann, Claus-Daniel; Döllner, Jürgen; Eichhorn, Michael; Heinzelmann, Michael in International Journal of Heritage in the Digital Era (IJHDE), (M. Ioannides, red.) (2012). 1(1) 45-74.
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HerausgeberIoannides, Marinos
URNhttp://dx.doi.org/10.1260/2047-4970.1.1.45
AbstractThe communication of cultural heritage in public spaces such as museums or exhibitions, gain more and more importance during the last years. The possibilities of interactive 3D applications open a new degree of freedom beyond the mere presentation of static visualizations, such as pre-produced video or image data. A user is now able to directly interact with 3D virtual environments that enable the depiction and exploration of digital cultural heritage artifacts in real-time. However, such technology requires concepts and strategies for guiding a user throughout these scenarios, since varying levels of experiences within interactive media can be assumed. This paper presents a concept as well as implementation for communication of digital cultural heritage in public spaces, by example of the project Roman Cologne. It describes the results achieved by an interdisciplinary team of archaeologists, designers, and computer graphics engineers with the aim to virtually reconstruct an interactive high-detail 3D city model of Roman Cologne.
Concepts for Cartography-Oriented Visualization of Virtual 3D City Models.Semmo, Amir; Hildebrandt, Dieter; Trapp, Matthias; Döllner, Jürgen in Photogrammetrie - Fernerkundung - Geoinformation (PFG) (2012). (4) 455-465.
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URNhttp://dx.doi.org/10.1127/1432-8364/2012/0131
AbstractVirtual 3D city models serve as an effective medium with manifold applications in geoinformation systems and services. To date, most 3D city models are visualized using photorealistic graphics. But an effective communication of geoinformation significantly depends on how important information is designed and cognitively processed in the given application context. One possibility to visually emphasize important information is based on non-photorealistic rendering, which comprehends artistic depiction styles and is characterized by its expressiveness and communication aspects. However, a direct application of non-photorealistic rendering techniques primarily results in monotonic visualization that lacks cartographic design aspects. In this work, we present concepts for cartography-oriented visualization of virtual 3D city models. These are based on coupling non-photorealistic rendering techniques and semantics-based information for a user, context, and media-dependent representation of thematic information. This work highlights challenges for cartography-oriented visualization of 3D geovirtual environments, presents stylization techniques and discusses their applications and ideas for a standardized visualization. In particular, the presented concepts enable a real-time and dynamic visualization of thematic geoinformation.
Interactive Visualization of Generalized Virtual 3D City Models using Level-of-Abstraction Transitions.Semmo, Amir; Trapp, Matthias; Kyprianidis, Jan Eric; Döllner, Jürgen in Computer Graphics Forum (2012). 31(3) 885--894.
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URNhttp://dx.doi.org/10.1111/j.1467-8659.2012.03081.x
AbstractVirtual 3D city models play an important role in the communication of complex geospatial information in a growing number of applications, such as urban planning, navigation, tourist information, and disaster management. In general, homogeneous graphic styles are used for visualization. For instance, photorealism is suitable for detailed presentations, and non-photorealism or abstract stylization is used to facilitate guidance of a viewer's gaze to prioritized information. However, to adapt visualization to different contexts and contents and to support saliency-guided visualization based on user interaction or dynamically changing thematic information, a combination of different graphic styles is necessary. Design and implementation of such combined graphic styles pose a number of challenges, specifically from the perspective of real-time 3D visualization. In this paper, the authors present a concept and an implementation of a system that enables different presentation styles, their seamless integration within a single view, and parametrized transitions between them, which are defined according to tasks, camera view, and image resolution. The paper outlines potential usage scenarios and application fields together with a performance evaluation of the implementation.
Challenges and Approaches for the Visualization of Movement Trajectories in 3D Geovirtual EnvironmentsBuschmann, Stefan; Trapp, Matthias; Döllner, Jürgen (2012).
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AbstractThe visualization of trajectories and their attributes represents an essential functionality for spatio-temporal data visualization and analysis. Many visualization methods, however, focus mainly on sparse 2D movements or consider only the 2D components of movements. This paper is concerned with true 3D movement data, i.e., movements that take place in the three-dimensional space and which characteristics significantly depend an all dimensions. In this case, spatio-temporal visualization approaches need to map all three spatial dimensions together with required mappings for associated attributes. We describe visualization approaches for true 3D movement data and evaluate their application within 3D geovirtual environments. We also identify challenges and propose approaches for the interactive visualization of 3D movement data using 3D geovirtual environments as scenery.
Concepts for Automatic Generalization of Virtual 3D Landscape Models.Glander, Tassilo; Trapp, Matthias; Döllner, Jürgen in gis.SCIENCE (2012). 25(1) 18-23.
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AbstractThis paper discusses concepts for the automatic generalization of virtual 3D landscape models. As complexity, heterogeneity, and diversity of geodata that constitute landscape models are constantly growing, the need for landscape models that generalize their contents to a consistent, coherent level-of-abstraction and information density becomes an essential requirement for applications such as in conceptual landscape design, simulation and analysis, and mobile mapping. We discuss concepts of generalization and working principles as well as the concept of level-of-abstraction. We furthermore present three exemplary automated techniques for generalizing 3D landscape models, including a geometric generalization technique that generates discrete iso-surfaces of 3D terrain models in real-time, a geometric generalization technique for site and building models, and a real-time generalization lens technique.
Towards Comprehensible Digital 3D Maps.Pasewaldt, Sebastian; Semmo, Amir; Trapp, Matthias; Döllner, Jürgen M. Jobst (red.) (2012). 261-276.
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HerausgeberJobst, Markus
AbstractDigital mapping services have become fundamental tools in economy and society to provide domain experts and non-experts with customized, multi-layered map contents. In particular because of the continuous advancements in the acquisition, provision, and visualization of virtual 3D city and landscape models, 3D mapping services, today, represent key components to a growing number of applications, like car navigation, education, or disaster management. However, current systems and applications providing digital 3D maps are faced by drawbacks and limitations, such as occlusion, visual clutter, or insufficient use of screen space, that impact an effective comprehension of geoinformation. To this end, cartographers and computer graphics engineers developed design guidelines, rendering and visualization techniques that aim to increase the effectiveness and expressiveness of digital 3D maps, but whose seamless combination has yet to be achieved. This work discusses potentials of digital 3D maps that are based on combining cartography-oriented rendering techniques and multi-perspective views. For this purpose, a classification of cartographic design principles, visualization techniques, as well as suitable combinations are identified that aid comprehension of digital 3D maps. According to this classification, a prototypical implementation demonstrates the benefits of multi-perspective and non-photorealistic rendering techniques for visualization of 3D map contents. In particular, it enables (1) a seamless combination of cartography-oriented and photorealistic graphic styles while (2) increasing screen-space utilization, and (3) simultaneously directing a viewer’s gaze to important or prioritized information.
Concepts for Automatic Generalization of Virtual 3D Landscape Models.Glander, Tassilo; Trapp, Matthias; Döllner, Jürgen E. Buhmann, Ervin, S., Tomlin, D., Pietsch, M. (reds.) (2011). 127-135.
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HerausgeberBuhmann, Erich and Ervin, Stephen and Tomlin, Dana and Pietsch, Matthias
AbstractThis paper discusses concepts for the automatic generalization of virtual 3D landscape models. As complexity, heterogeneity, and diversity of geodata that constitute landscape models are constantly growing, the need for landscape models that generalize their contents to a consistent, coherent level-of-abstraction and information density becomes an essential requirement for applications such as in conceptual landscape design, simulation and analysis, and mobile mapping. We discuss concepts of generalization and working principles as well as the concept of level-of-abstraction. We furthermore present three exemplary automated techniques for generalizing 3D landscape models, including a geometric generalization technique that generates discrete iso-surfaces of 3D terrain models in real-time, a geometric generalization technique for site and building models, and a real-time generalization lens technique.
Multiscale Visualization of 3D Geovirtual Environments Using View-Dependent Multi-Perspective Views.Pasewaldt, Sebastian; Trapp, Matthias; Döllner, Jürgen in Journal of WSCG, (V. Skala, red.) (2011). 19(3) 111-118.
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HerausgeberSkala, Václav
Abstract3D geovirtual environments (GeoVEs), such as virtual 3D city models or landscape models, are essential visualization tools for effectively communicating complex spatial information. In this paper, we discuss how these environments can be visualized using multi-perspective projections based on view-dependent global deformations. Multi-perspective projections enable 3D visualization similar to panoramic maps, increasing overview and information density in depictions of 3D GeoVEs. To make multi-perspective views an effective medium, they must adjust to the orientation of the virtual camera controlled by the user and constrained by the environment. Thus, changing multi-perspective camera configurations typically require the user to manually adapt the global deformation — an error prone, non-intuitive, and often time-consuming task. Our main contribution comprises a concept for the automatic and view-dependent interpolation of different global deformation preset configurations. Applications and systems that implement such view-dependent global deformations, allow users to smoothly and steadily interact with and navigate through multi-perspective 3D GeoVEs.
Colonia3D.Trapp, Matthias; Semmo, Amir; Döllner, Jürgen (2011). 201-212.
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AbstractDieser Beitrag stellt die Ergebnisse des interdisziplinären Projektes Colonia3D - Visualisierung des Römischen Kölns vor. Die digitale 3D Rekonstruktion des antiken Köln ist das Ergebnis eines gemeinsamen Forschungsprojekts des Archäologischen Instituts der Universität zu Köln, der Köln International School of Design (KISD) der Fachhochschule Köln, des Hasso-Plattner Instituts an der Universität Potsdam und des Römisch Germanischen Museums (RGM) Köln. Der Beitrag präsentiert die wesentlichen Konzepte dieses interaktiven, auf Museen ausgerichteten 3D-Informationssystems, beschreibt verschiedene Präsentationsmodi und deren technische Umsetzung. Er diskutiert Vorgehensweisen und Interaktionskonzepte, die den Benutzer während der Erkundung und Bewegung im virtuellen 3D-Stadtmodell unterstützen. Weiter werden die Techniken für den Austausch, die Aufbereitung und die Optimierung komplexer 3D-Datensätze beschrieben sowie Potenziale für digitale Museen und Ausstellungen skizziert. Der vorgestellte Ansatz stellt insbesondere eine IT-Lösung für einen vereinfachten, räumlich-kontextintegrierten informellen Wissenszugang zu archäologischer Fachinformation dar.
Strategies for Visualizing 3D Points-of-Interest on Mobile Devices.Trapp, Matthias; Schneider, Lars; Lehmann, Christine; Holz, Norman; Döllner, Jürgen in Journal of Location Based Services (JLBS) (2011). 5(2) 79-99.
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URNhttp://dx.doi.org/http://dx.doi.org/10.1080/17489725.2011.579579
Abstract3D virtual environments are increasingly used as general-purpose medium for communicating spatial information. In particular, virtual 3D city models have numerous applications such as car navigation, city marketing, tourism, and gaming. In these applications, points-of-interest (POI) play a major role since they typically represent features relevant for specific user tasks and facilitate effective user orientation and navigation through the 3D virtual environment. In this paper, we present strategies that aim at effectively visualizing points-of-interest in a 3D virtual environment used on mobile devices. Here, we additionally have to face the "keyhole" situation, i.e., the users can realize only a small part of the environment due to the limited view space and resolution. For the effective visualization of points-of-interest in 3D virtual environments we propose to combine specialized occlusion management for 3D scenes together with visual cues that handle out-of-frame points-of-interest. We also discuss general aspects and definitions of points-of-interest in the scope of 3D models and outline a prototype implementation of the mobile 3D viewer application based on the presented concepts. In addition, we give a first performance evaluation with respect to rendering speed and power consumptions.
Ansätze zur kartographischen Gestaltung von 3D-Stadtmodellen.Semmo, Amir; Trapp, Matthias; Döllner, Jürgen in Publikationen der Deutschen Gesellschaft für Photogrammetrie, Fernerkundung und Geoinformation e.V. (2011). (Vol. 20) 473-482.
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AbstractInteraktive virtuelle 3D-Stadtmodelle haben sich zu einem bewährten Medium für die effektive und effiziente Kommunikation von Geoinformation entwickelt. Sie präsentieren eine spezialisierte Form geovirtueller Umgebungen und sind gekennzeichnet durch ein zugrunde liegendes 3D-Geländemodell, einer darin befindlichen 3D-Bebauung sowie des dazu komplementären Straßen-, Grünflächen- und Naturraumes. 3D-Stadtmodell-Systeme ermöglichen es dem Nutzer, sich im Modell interaktiv zu bewegen und sie stellen die Grundfunktionen für die Exploration, Analyse, Präsentation und das Editieren der raumbezogenen Information bereit. Besonders im Gebiet der kartenähnlichen und kartenverwandten 3D-Darstellungen stellen u.a. automatische Verfahren und Techniken zur Stilisierung und Abstraktion von Objekten eines 3D Stadtmodell ein Hauptproblem für die interaktive 3D-Bildsynthese dar. Hier spielt insbesondere die Abstraktion und Illustration potentiell wichtiger Information und somit die Reduzierung der kognitiven Belastung des Nutzers eine tragende Rolle. Diesbezüglich sind Verfahren und Techniken zur nicht-photorealistischen Bildsynthese ein bewährtes Mittel der Computergrafik, deren direkte Anwendung auf ein komplettes 3D-Stadtmodell jedoch häufig monotone sowie gestalterisch und kartographisch stark eingeschränkte Resultate liefert. Eine effiziente und kontextsensitive Kommunikation von 3D-Geoinformation bedarf jedoch der Kopplung von Objektsemantik und Abstraktionsverfahren. Diese Arbeit präsentiert ein Konzept und dessen Umsetzung, das die Auswahl und Parametrisierung von nicht-photorealistischen Darstellungstechniken auf Basis von Objektsemantiken erlaubt (Abbildung 1). Dies ermöglicht die Zuweisung unterschiedlicher automatischer Abstraktionstechniken zu Objekten und Objektgruppen. Der vorgestellte Ansatz ist echtzeitfähig und erlaubt eine interaktive Klassifikation von Objekten und Features zur Laufzeit, wodurch sich u.a. Szenarien zur interaktiven Exploration von thematisch-stilisierten Features bzw. feature-bezogenen Daten visualisieren lassen. Dieser Ansatz eröffnet Möglichkeiten für eine gezielte und systematische kartographische Gestaltung von 3D-Stadtmodellen sowie deren echtzeitfähige Implementierung durch entsprechende 3D-Visualisierungsdienste.
Interactive Rendering Techniques for Highlighting in 3D Geovirtual Environments.Trapp, Matthias; Beesk, Christian; Pasewaldt, Sebastian; Jürgen, Döllner in Lecture Notes in Geoinformation & Cartography (2010).
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Abstract3D geovirtual environments (GeoVE), such as virtual 3D city and landscape models became an important tool for the visualization of geospatial information. Highlighting is an important component within a visualization framework and is essential for the user interaction within many applications. It enables the user to easily perceive active or selected objects in the context of the current interaction task. With respect to 3D GeoVE, it has a number of applications, such as the visualization of user selections, data base queries, as well as navigation aid by highlighting way points, routes, or to guide the user attention. The geometrical complexity of 3D GeoVE often requires specialized rendering techniques for the real-time image synthesis. This paper presents a framework that unifies various highlighting techniques and is especially suitable for the interactive rendering 3D GeoVE of high geometrical complexity.
Interactive Rendering to Perspective Texture-Atlases.Trapp, Matthias; Döllner, Jürgen S. Seipel, Lensch, H. (reds.) (2010). 81-84.
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HerausgeberSeipel, Stefan and Lensch, Hendrik
AbstractThe image-based representation of geometry is a well known concept in computer graphics. Due to z-buffering, the derivation of such representations using render-to-texture delivers only information of the nearest fragments. Often, transparency-based visualization techniques, e.g., ghost views, also require information of occluded fragments. These can be captured using multi-pass rendering techniques such as depth-peeling or stencil-routed A-buffers on a per-fragment basis. This paper presents an alternative rendering technique that enables the derivation image-based representations on a per-object or per-primitive level within a single rendering pass. We use a dynamic 3D texture atlas that is parameterized on a per-frame basis. Then, prior to rasterization, the primitives are transformed to their respective position within the texture atlas, using vertex-displacement in screen space.
Communication of Digital Cultural Heritage in Public Spaces by the Example of Roman Cologne.Trapp, Matthias; Semmo, Amir; Pokorski, Rafael; Herrmann, Claus-Daniel; Döllner, Jürgen; Eichhorn, Michael; Heinzelmann, Michael in Lecture Notes in Computer Science (LNCS), M. Ioannides (red.) (2010). 262-276.
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HerausgeberIoannides, M.
AbstractThe communication of cultural heritage in public spaces such as museums or exhibitions, gain more and more importance during the last years. The possibilities of interactive 3D applications open a new degree of freedom beyond the mere presentation of static visualizations, such as pre-produced video or image data. A user is now able to directly interact with 3D virtual environments that enable the depiction and exploration of digital cultural heritage artefacts in real-time. However, such technology requires concepts and strategies for guiding a user throughout these scenarios, since varying levels of experiences within interactive media can be assumed. This paper presents a concept as well as implementation for communication of digital cultural heritage in public spaces, by example of the project Roman Cologne. It describes the results achieved by an interdisciplinary team of archaeologists, designers, and computer graphics engineers with the aim to virtually reconstruct an interactive high-detail 3D city model of Roman Cologne.
3D Isocontours – Real-time Generation and Visualization of 3D Stepped Terrain Models.Glander, Tassilo; Trapp, Matthias; Döllner, Jürgen S. Seipel, Lensch, H. (reds.) (2010). 17-20.
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HerausgeberSeipel, Stefan and Lensch, Hendrik
AbstractIsocontours (also isopleths, isolines, level sets) are commonly used to visualize real-valued data defined over a 2D plane according to a set of given isovalues. To support the 3D landscape metaphor for information visualization, a 3D stepped terrain can be derived by lifting and extruding isolines to their particular isovalue, but typically requires triangulation of the resulting surface representation in a preprocessing step. We present a concept and rendering technique for triangle-based terrain models that provide interactive, adaptive generation and visualization of such stepped terrains without preprocessing. Our fully hardware-accelerated rendering technique creates additional step geometry for each triangle intersecting an iso-plane on-the-fly. Further, an additional interpolation schema facilitates smooth transition between established 3D terrain visualization and its stepped variant.
Towards an indoor level-of-detail model for route visualization.Hagedorn, Benjamin; Trapp, Matthias; Glander, Tassilo; Döllner, Jürgen (2009). 692--697.
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URNhttp://dx.doi.org/10.1109/MDM.2009.118
Interaktive Visualisierung des Römischen Kölns.Trapp, Matthias (2009).
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3D Wayfinding Choremes: A Cognitively Motivated Representation of Route Junctions in Virtual Environments.Glander, Tassilo; Peters, Denise; Trapp, Matthias; Döllner, Jürgen in Lecture Notes in Geoinformation and Cartography (2009). 407--427.
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URNhttp://dx.doi.org/10.1007/978-3-642-00318-9_21
AbstractResearch in cognitive sciences suggests that orientation and navigation along routes can be improved if the graphical representation is aligned with the user’s mental concepts of a route. In this paper, we analyze an existing 2D schematization approach called wayfinding choremes and present an implementation for virtual 3D urban models, transferring the approach to 3D. To create the virtual environment, we transform the junctions of a route defined for a given road network to comply with the eight sector model, that is, outgoing legs of a junction are slightly rotated to align with prototypical directions in 45° increments. Then, the adapted road network is decomposed into polygonal block cells, the individual polygons being extruded to blocks and their facades textured. For the evaluation of our 3D wayfinding choreme implementation, we present an experiment framework allowing for training and testing subjects by a route learning task. The experimental framework can be parameterized flexibly, exposing parameters to the conductor. We finally give a sketch of a user study by identifying hypotheses, indicators, and, hence, experiments to be done.
Enhancing Interactive Non-Planar Projections of 3D Geovirtual Environments with Stereoscopic Imaging.Trapp, Matthias; Lorenz, Haik; Jobst, Markus; Döllner, Jürgen in Lecture Notes in Geoinformation and Cartography, M. Buchroithner (red.) (2009). 281-296.
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HerausgeberBuchroithner, Manfred
AbstractStereo rendering, as an additional visual cue for humans, is an important method to increase the immersion into 3D virtual environments. Stereo pairs synthesized for the left and right eye are displayed in a way that the human visual system interprets as 3D perception. Stereoscopy is an emerging field in cinematography and gaming. While generating stereo images is well known for standard projections, the implementation of stereoscopic viewing for interactive non-planar single-center projections, such as cylindrical and spherical projections, is still a challenge. This paper presents the results of adapting an existing image-based approach for generating interactive stereoscopic non-planar projections for polygonal scenes on consumer graphics hardware. In particular, it introduces a rendering technique for generating image-based, non-planar stereo pairs within a single rendering pass. Further, this paper presents a comparison between the image-based and a geometry-based approach with respect to selected criteria.
Interactive Stereo Rendering For Non-Planar Projections of 3D Virtual Environments.Trapp, Matthias; Lorenz, Haik; Döllner, Jürgen (2009). 199--204.
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AbstractStereo rendering, as an additional visual cue for humans, is an important method to increase the immersion into 3D virtual environments. Stereo pairs synthesized for the left and right eye are displayed in a way that the human visual system interprets as 3D perception. Stereoscopy is an emerging field in cinematography and gaming. While generating stereo images is well known for standard projections, the implementation of stereoscopic viewing for non-planar single-center projections, such as cylindrical and spherical projections in real-time, is still a challenge. This paper presents the results of adapting existing image-based and object-based approaches for generating interactive stereoscopic non-planar projections for polygonal scenes on consumer graphics hardware. In particular, it introduces a rendering technique for generating image-based, non-planar stereo pairs within a single rendering pass. Further, this paper presents a comparison between these both approaches with respect to selected criteria.
Towards an Indoor Level-of-Detail Model for Route Visualization.Hagedorn, Benjamin; Trapp, Matthias; Glander, Tassilo; Döllner, Jürgen (2009). 692--697.
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URNhttp://dx.doi.org/10.1109/MDM.2009.118
AbstractIndoor routing represents an essential feature required by applications and systems that provide spatial information about complex sites, buildings and infrastructures such as in the case of visitor guidance for trade fairs and customer navigation at airports or train stations. Apart from up-to-date, precise 3D spatial models these systems and applications need user interfaces as core system components that allow users to efficiently express navigation goals and to effectively visualize routing information. For interoperable and flexible indoor routing systems, common specifications and standards for indoor structures, objects, and relationships are needed as well as for metadata such as data quality and certainty. In this paper, we introduce a classification of indoor objects and structures taking into account geometry, semantics, and appearance, and propose a level-of-detail model for them that supports the generation of effective indoor route visualization.
Strategies for Visualizing Points-of-Interest of 3D Virtual Environments on Mobile Devices.Trapp, Matthias; Schneider, Lars; Holz, Norman; Döllner, Jürgen (2009).
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Abstract3D virtual environments are increasingly used as general- purpose medium for communicating spatial information. In particular, virtual 3D city models have numerous applications such as car naviga- tion, city marketing, tourism, and gaming. In these applications, points- of-interest (POI) play a major role since they typically represent features relevant for speci�c user tasks and facilitate eective user orientation and navigation through the 3D virtual environment. In this paper, we present strategies that aim at eectively visualizing points-of-interest in a 3D vir- tual environment used on mobile devices. Here, we additionally have to face the "keyhole" situation, i.e., the users can realize only a small part of the environment due to the limited view space and resolution. For the eective visualization of points-of-interest in 3D virtual environments we propose to combine specialized occlusion management for 3D scenes to- gether with visual cues that handle out-of-frame points-of-interest. We also discuss general aspects and de�nitions of points-of-interest in the scope of 3D models and outline a prototype implementation of the mo- bile 3D viewer application based on the presented concepts. In addition, we give a �rst performance evaluation with respect to rendering speed and power consumptions.
Dynamic Mapping of Raster-Data for 3D Geovirtual Environments.Trapp, Matthias; Döllner, Jürgen (2009). 387--392.
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URNhttp://dx.doi.org/http://doi.ieeecomputersociety.org/10.1109/IV.2009.28
AbstractInteractive 3D geovirtual environments (GeoVE), such as 3D virtual city and landscape models, are important tools to communicate geospatial information. Usually, this includes static polygonal data (e.g., digital terrain model) and raster data (e.g., aerial images) which are composed from multiple data sources during a complex, only partial automatic pre-processing step. When dealing with highly dynamic geo-referenced raster data, such as the propagation of fires or floods, this pre-processing step hinders the direct application of 3D GeoVE for decision support systems. To compensate for this limitation, this paper presents a concept for dynamically mapping multiple layers of raster for interactive GeoVE. The implementation of our rendering technique is based on the concept of projective texture mapping and can be implemented efficiently using consumer graphics hardware. Further, this paper demonstrates the flexibility of our technique using a number of typical application examples.
Interaktive, multiperspektivische Ansichten für geovirtuelle 3D-Umgebungen.Lorenz, Haik; Trapp, Matthias; Döllner, Jürgen in Kartographische Nachrichten (2009). 04 175-181.
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AbstractIn diesem Beitrag werden Visualisierungstechniken vorgestellt, die auf den Gestaltungsprinzipien von Panoramakarten und Detail- und Überblicksdarstellungen beruhen. Die Techniken generieren multiperspektivische Ansichten für geovirtuelle 3D-Umgebungen, insbesondere für zwei häufig benötigte Ansichtsformen, die Vogelperspektive und die Fußgängerperspektive. Die Techniken tragen dazu bei, die Bandbreite der computergestützten, interaktiven 3D-Darstellungen zur Visualisierung von virtuellen 3D-Raummodellen zu erweitern und die Effektivität raumbezogener Informationsdarstellungen im Hinblick auf Ortsbewusstsein und Informationsgehalt zu verbessern.
A Generalization Approach for 3D Viewing Deformations of Single-Center Projections.Trapp, Matthias; Döllner, Jürgen J. Braz, Nunes, N. J., Pereira, J. M. (reds.) (2008). 162--170.
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HerausgeberBraz, José and Nunes, Nuno Jardim and Pereira, Joao Madeiras
AbstractThis paper presents a novel image-based approach to efficiently generate real-time non-planar projections of arbitrary 3D scenes such as panorama and fish-eye views. The real-time creation of such projections has a multitude of applications, e.g., in geovirtual environments and in augmented reality. Our rendering technique is based on dynamically created cube map textures in combination with shader programs that calculate the specific projections. We discuss two different approaches to create such cubemaps and introduce possible optimizations. Our technique can be applied within a single rendering pass, is easy to implement, and exploits the capability of modern programmable graphics hardware completely. Further, we present an approach to customize and combine different planar as well as non-planar projections. We have integrated our technique into an existing real-time rendering framework and demonstrate its performance on large scale datasets such as virtual 3D city and terrain models.
Konzepte für die Generalisierung von 3D-Gebäudemodellen.Glander, Tassilo; Trapp, Matthias; Döllner, Jürgen (2008). (Vol. 41) 33--45.
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Efficient Representation of Layered Depth Images for Real-time Volumetric Tests.Trapp, Matthias; Döllner, Jürgen I. S. Lim, Tang, W. (reds.) (2008). 9--16.
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HerausgeberLim, Ik Soo and Tang, Wen
AbstractRepresenting Layered Depth Images (LDI) as 3D texture can be used to approximate complex, arbitrarily shaped volumes on graphics hardware. Based on this concept, a number of real-time applications such as collision detection or 3D clipping against multiple volumes can be implemented efficiently using programmable hardware. One major drawback of this image-based representation is the high video memory consumption. To compensate that disadvantage, this paper presents a concept and associated algorithms that enable a lossless, efficient LDI representation which is especially designed for the usage within shader programs. The concept comprises the application of a viewpoint selection, a cropping, and a compression algorithm. We evaluated our algorithm with different test cases and show possible use cases.
Techniques For The Interactive Exploration Of High-Detail 3D Building Reconstruction Using The Example Of Roman Cologne.Maass, Stefan; Trapp, Matthias; Kyprianidis, Jan Eric; Döllner, Jürgen; Eichhorn, M.; Pokorski, Rafael; Bäuerlein, Johannes; Hesberg, H. v. M. Loannides, Addison, A., Georgopoulos, A., Kalisperis, L. (reds.) (2008). 223--229.
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HerausgeberLoannides, M. and Addison, A. and Georgopoulos, A. and Kalisperis, L.
AbstractThis paper presents the results achieved by an interdisciplinary team of archaeologists, designers, and computer graphics engineers with the aim to virtually reconstruct an interactive high-detail 3D city model of Roman Cologne. We describe a content creation pipeline established to enable a flexible exchange and enhancement of building models, the applied optimization techniques necessary for real-time rendering, and the design of an application framework that enables the coupling of 3D visualizations with additional information in corresponding Adobe® Flash® widgets. Furthermore, we expose challenges arising by incorporating state-of-the-art visualization techniques, such as cut-away views, non-photorealistic rendering (NPR), and automated label placement. These techniques are used to enhance the interactive 3D environments, to enable for the presentation of interior structures, the precise communication what is hypothetic and what proven knowledge, and the integration of meta information.
Relief Clipping Planes for Real-Time Rendering.Trapp, Matthias; Döllner, Jürgen (2008).
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AbstractThe concept of clipping planes is well known in computer graphics and can be used to create cut-away views. But clipping against just analytical defined planes is not always suitable for communicating every aspect of such visualization. For example, in hand-drawn technical illustrations, artists tend to communicate the difference between a cut and a model feature by using non-regular, sketchy cut lines instead of straight ones. To enable this functionality in computer graphics, we present a technique for rendering relief clip planes in real-time. Therefore, we extend the clip plane equation with an additional offset map, which can be represented by a texture map that contains height values. Clipping is then performed by varying the clip plane equation with respect to such an offset map. Further, we propose a capping technique that enables the rendering of caps onto the clipped area to convey the impression of solid material. It avoids a re-meshing of a solid polygonal mesh after clipping is performed. Our approach is pixel precise, applicable in real-time, and takes fully advantage of graphics accelerators.
Generalization of Single-Center Projections Using Projection Tile Screens.Trapp, Matthias; Döllner, Jürgen in Advances in Computer Graphics and Computer Vision (VISIGRAPP), J. Braz, Ranchordas, A. K., Pereira, J. M., Araújo, H. J. (reds.) (2008).
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HerausgeberBraz, José and Ranchordas, Alpesh Kumar and Pereira, João Madeiras and Araújo, Hélder J.
Real-Time Volumetric Tests Using Layered Depth Images.Trapp, Matthias; Döllner, Jürgen K. Mania, Reinhard, E. (reds.) (2008). 235--238.
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HerausgeberMania, K. and Reinhard, E.
AbstractThis paper presents a new approach for performing efficiently 3D point-in-volume tests for solid and arbitrary complex shapes. It classifies a 3D point as inside or outside of a solid specified by 3D polygonal geometry. Our technique implements a basic functionality that offers a wide range of applications such as clipping, collision detection, interactive rendering of multiple 3D lenses as well as rendering using multiple styles. It is based on an extension of layered depth images (LDI) in combination with shader programs. An LDI contains layers of unique depth complexity and is represented by a 3D volume texture. The test algorithm transforms a 3D point into an LDI texture space and, then, performs ray marching through the depth layers to determine its classification. We show how to apply real-time volumetric tests to implement 3D clipping and rendering using multiple styles. In addition, we discuss limitations and possible improvements.
Interactive Multi-Perspective Views of Virtual 3D Landscape and City Models.Lorenz, Haik; Trapp, Matthias; Jobst, Markus; Döllner, Jürgen in Lecture Notes in Geoinformation and Cartography, L. Bernard, Friis-Christensen, A., Pundt, H. (reds.) (2008). 301--321.
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HerausgeberBernard, Lars and Friis-Christensen, Anders and Pundt, Hardy
AbstractBased on principles of panorama maps we present an interactive visualization technique that generates multi-perspective views of complex spatial environments such as virtual 3D landscape and city models. Panorama maps seamlessly combine easily readable maps in the foreground with 3D views in the background – both within a single image. Such nonlinear, non-standard 3D projections enable novel focus & context views of complex virtual spatial environments. The presented technique relies on global space deformation to model multi-perspective views while using a standard linear projection for rendering which enables single-pass processing by graphics hardware. It automatically configures the deformation in a view-dependent way to maintain the multi-perspective view in an interactive environment. The technique supports different distortion schemata beyond classical panorama maps and can seamlessly combine different visualization styles of focus and context areas. We exemplify our approach in an interactive 3D tourist information system.
3D Generalization Lenses for Interactive Focus + Context Visualization of Virtual City Models.Trapp, Matthias; Glander, Tassilo; Buchholz, Henrik; Döllner, Jürgen (2008). 356--361.
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URNhttp://dx.doi.org/http://doi.ieeecomputersociety.org/10.1109/IV.2008.18
AbstractFocus + context visualization facilitates the exploration of complex information spaces. This paper proposes 3D generalization lenses, a new visualization technique for virtual 3D city models that combines different levels of structural abstraction. In an automatic preprocessing step, we derive a generalized representation of a given city model. At runtime, this representation is combined with a full-detail representation within a single view based on one or more 3D lenses of arbitrary shape. Focus areas within lens volumes are shown in full detail while excluding less important details of the surrounding area. Our technique supports simultaneous use of multiple lenses associated with different abstraction levels, can handle overlapping and nested lenses, and provides interactive lens modification.
Automated Combination of Real-Time Shader Programs.Trapp, Matthias; Döllner, Jürgen P. Cignoni, Sochor, J. (reds.) (2007). 53--56.
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HerausgeberCignoni, P. and Sochor, J.
AbstractThis work proposes an approach for automatic and generic runtime-combination of high-level shader programs. Many of recently introduced real-time rendering techniques rely on such programs. The fact that only a single program can be active concurrently becomes a main conceptual problem when embedding these techniques into middleware systems or 3D applications. Their implementations frequently demand for a combined use of individual shader functionality and, therefore, need to combine existing shader programs. Such a task is often timeconsuming, error-prone, requires a skilled software engineer, and needs to be repeated for each further extension. Our extensible approach solves these problems efficiently: It structures a shader program into code fragments, each typed with a predefined semantics. Based on an explicit order of those semantics, the code fragments of different programs can be combined at runtime. This technique facilitates the reuse of shader code as well as the development of extensible rendering frameworks for future hardware generations. We integrated our approach into an object-oriented high-level rendering system.
Analysis and Exploration of Virtual 3D-Citymodels using 3D Information Lenses.Trapp, Matthias (2007).
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AbstractThis thesis addresses real-time rendering techniques for 3D Information-Lenses, which are based on the focus & context metaphor. It analyzes, conceives, implements and reviews its applicability to objects and structures of virtual 3D city models. In contradiction to digital terrain models, the application of focus & context visualization to virtual 3D city models is barely researched. However, the purposeful visualization of contextual data of is extreme importance for the interactive exploration and analysis of this field. Programmable hardware enables the implementation of new lens-techniques, which allows the augmentation of the perceptive and cognitive quality of the visualization, compared to classical perspective projections. A set of 3D information-lenses is integrated into a 3D scene graph system: 1.) Occlusion Lenses modify the appearance of virtual 3D city-model objects in order to resolve their occlusion and consequently facilitate the navigation. 2.) Best-View Lenses display city-model objects in a priority-based manner and mediate their meta-information. Thus, they support exploration and navigation of virtual 3D-city-models. 3.) Color and deformation lenses modify the appearance and geometry of 3D city-models to facilitate their perception. The present techniques for 3D information lenses and the application to virtual 3D city models clarify their potential for interactive visualization and form a base for further development.
A Concept of Effective Landmark Depiction in Geovirtual 3D Environments by View-Dependent Deformation.Glander, Tassilo; Trapp, Matthias; Döllner, Jürgen (2007).
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AbstractLandmarks represent elements of geovirtual 3D environments with outstanding importance for user orientation. Especially, they facilitate navigation and exploration within virtual 3D city models. This paper presents a novel concept for the real-time depiction of landmarks that effectively emphasizes these 3D objects by improving their visibility with respect to their surrounding areas and the current 3D viewing settings. The concept is based on scaling landmark geometry according to an importance function while simultaneously adjusting the corresponding surrounding region. The amplification of landmarks takes into account the current camera parameters. To reduce visual artifacts caused by this multi-scale presentation, e.g., geometry intersections, the surrounding objects of each landmark are adapted according to a deformation field that encodes the displacement and scaling transformations. An individual weight coefficient can be defined that denotes the landmark’s importance. To render a collection of weighted landmarks within a virtual 3D city model, the technique accumulates their associated, weighted deformation fields in a view-dependent way. Our concept provides a flexible solution for the importance-driven enhancement of objects within interactive geovirtual 3D environments and aims at improving the perceptual and cognitive quality of their display. In particular, the concept can be applied to systems and applications that use abstracted, generalized virtual 3D city models such as in the fields of car and pedestrian navigation, disaster management, and spatial data mining.

Teaching Activities

Courses at HPI (Responsible for lecturing and grading)

Winter 2019/2020 (M): Visual Media Data Processing
Winter 2018/2019 (B): User Interface Programming
Winter 2017/2018 (B): Computer Graphics I
Summer 2017 (M): Image & Video Processing Techniques
Summer 2015 (M): Introduction to Visualization
Winter 2014/2015 (B): Computer Graphics II
Winter 2013/2014 (B): Computer Graphics II
Summer 2013 (M): Geovisualization

Courses at HPI (Responsible for lecturing and tutoring)

Summer 2012 (B): Computer Graphics I
Winter 2011/2012 (B): Computer Graphics II
Summer 2010 (B): Programming of 3D Applications
Winter 2009/2010 (M): Geovisualization II
Summer 2009 (M): Geovisualization I
Summer 2008 (M): Rendering Techniques

Courses at University of Potsdam (Responsible for lecturing and tutoring)

Winter 2002/2003: Operating Systems II
Summer 2002: Operating Systems I

Seminars at HPI (Responsible for lecturing, tutoring, and grading)

Winter 2019/2020 (M): Advanced Visual Media Enhacement
Winter 2019/2020 (B): Visual Media Enhacement
Summer 2019 (M): Visual Media Processing
Summer 2019 (B): Introduction to Visual Media Processing
Summer 2018 (M): Selected Topics in Video & Image Analytics
Winter 2017/2018 (M): Video Abstraction Techniques
Summer 2017 (M): Advanced Information Visualization
Winter 2016/2017 (M): Processing and Visualization of 3D Geodata
Winter 2016/2017 (B): Bildverarbeitungsalgorithmen
Summer 2016 (M): Image Processing - Concepts and Techniques
Summer 2016 (M): Methods and Techniques of Geospatial Visualization
Summer 2016 (B): Geoinformationstechnologien
Winter 2015/2016 (B): Image and Videoprocessing using OpenGL ES for Mobile Devices
Summer 2015 (M): Spatial Analytics
Winter 2014/2015 (M): Geoinformation Technologies
Summer 2014 (M): Information Visualization
Winter 2013/2014 (M): Information Visualization
Summer 2013 (M): Geovisualization
Winter 2012/2013 (M): Concepts and Techniques of 3D-Visualization
Summer 2011 (M): Multimedia/Graphics Libraries & Systems
Winter 2010/2011 (B): Game Programming
Summer 2010 (M): Information and Geovisualization
Winter 2009/2010 (B): Game Programming
Winter 2008/2009 (M): Focus+Context Visualization in 3D Geovirtual Environments
Winter 2007/2008 (B): Seminar & Lab Computer graphics Systems/VRS
Summer 2007 (B): Seminar & Lab Computer graphics Systems/VRS

Bachelor Students (Co-)Supervision:

Architectural Design and Implementation of a Web-App for Service-based Image and Video Abstraction
Mino Böckmann, Bachelor Thesis, 2019
Real-Time Analytics of Video Streams
Jakob Mache, Bachelor Thesis, 2019
Service-based Integration and Deployment of Video Skimming Techniques
Robert Schröter, Bachelor Thesis, 2019
Service-based Integration and Deployment of Video Abstraction Techniques
Ole Wegen, Bachelor Thesis, 2019
Service-based Integration and Development of Video Storyboard Technique
Jakob Mache, Bachelor Thesis, 2019
Service-based Image and Video Processing Using Neural Networks
Markus Brand, Bachelor Thesis, 2018
Design and Implementation of a File Format for Representation of Video Processing Pipelines
Erik Brendel, Bachelor Thesis, 2018
Integration of Temporal Video Abstraction Techniques on Mobile Devices
Anastasia Phaedra Goudoulaki-Adamopoulou, Bachelor Thesis, 2018
Applications of Service-based Image and Video Processing Interfaces
Merlin de la Haye, Bachelor Thesis, 2018
Design and Implementation of a Documentation Service for Visual Computing Assets
Ludwig Kitschke, Bachelor Thesis, 2018
Assisted Interaction Techniques for Image Editing
Fabian Pottbäcker, Bachelor Thesis, 2018
A Framework for Editing and Execution of Image and Video Processing Techniques on Mobile Devices
Tobias Dürschmid, Bachelor Thesis, 2017
C++ Image and Video Processing Framework for Desktop and Server Systems
Erik Griese, Bachelor Thesis, 2017
GPU-accelerated Style Transfer on Mobile Devices using Feed-forward Convolutional Neural Networks
Moritz Hilscher, Bachelor Thesis, 2017
Service-based Integration of Image and Video Processing Operations
Alexander Riese, Bachelor Thesis, 2017
Design, Implementation and Web-based Provisioning of a Database for Image Processing Operations
Maximilian Söchting, Bachelor Thesis, 2017
Parameterization of Feed-forward Neural Networks for Style Transfer on Mobile Devices
Hendrik Tjabben, Bachelor Thesis, 2017

Master Students (Co-)Supervision:

Design and Implementation of a Service-based Stream-processing Component for Digital Videos
Florian Wagner, Master Thesis, 2019
Design and Implementation of a SOA-based Web Application for Visualization and Interactive Exploration of Mobility Data using Reachability Maps
Jan Silbersiepe, Master Thesis, 2018
Focus+Context Visualization Techniques for Mobility Analytics
Marc Listemann, Master Thesis, 2017
Network-based Reachability-Map Visualization for Web Applications and Mobile Devices
Alexander Schoedon, Master Thesis, 2017
Design and Implementation of Level-of-Detail Representations for Georeferenced Thematic Data
Jan Ole Vollmer, Master Thesis, 2016
Natural Phenomena as Metaphors for Visualization of Trend Data in Interactive Software Maps
Hannes Würfel, Master Thesis, 2015
A GPU-based rendering Technique for Interactive Video Deformation
Benjamin-Heinz Meier, Master Thesis, 2015
Interactive Rendering Techniques for Focus+Context Visualization of virtual 3D Indoor Models
Alessandro Florio, Master Thesis, 2014
Concepts and Rendering Techniques for Level-of-Abstraction Transitions of 3D Geovirtual Environments
Amir Semmo, Master Thesis, 2011
Generalization of Street Networks as Strategy to Reduce Cognitive Efforts in Map Reading
Daryna Bronnykova, Master Thesis, 2011
View-dependent Global Deformations, for 3D Geovirtual Environments of Virtual 3D Landscape and City Models
Sebastian Pasewaldt, Master Thesis, 2010
Rendering von generalisierter Tiefenschärfe in interaktiven 3D virtuellen Umgebungen
Christian Beesk, Master Thesis, 2010
Generierung und Parametrisierung von 3D-Gebäudegeometrienin virtuellen 3D-Stadtmodellen
Mathias Pietsch, Diploma Thesis, 2007

Bachelor's Projects (Co-)Supervision:

2018/2019: Smart Image & Video Abstraction
Mino Böckmann, Jakob Mache, Robert Schröter, Ole Wegen, Jakob Wischner
2017/2018: Analysis, Compactification, and Stylization of Videos
Erik Brendel, Markus Brand, Merlin de la Haye, Pheadra Goulouaki, Ludwig Kitschke, Julian Müller, Fabian Pottbäcker
2016/2017: Image-Based and Temporal Video Abstraction
Tobias Dürschmid, Erik Griese, Moritz Hilscher, Alexander Riese, Maximilian Söchting, Hendrik Tjabben

Master's Projects (Co-)Supervision:

Summer 2019: Visual Analytics - Blocking Offensive Contents
Moritz Hilscher, Hendrik Raetz, Hendrik Tjabben
Winter 2015: Deep Learning for Smart Video: Using Mass Knowledge for the Automatic Stylization of Images and Videos
Anne Gropler, Alexander Lehmann, Leander Neiß, Max Reimann, Jan Ole Vollmer
Summer 2015: Smart Video: Automatic video summarization and adaptive parametrization
Karsten Tausche, Astrid Thomschke, Christian Würz
Winter 2014: Service-based Architecture and Infrastructure for Video Processing
Robin Schreiber, Christoph Sterz, Wieland Hagen, Kirstin Heidler
Summer 2014: Video Analysis, Abstraction, and Summarization
Jaeyoon Jung, Benjamin-Heinz Meier, Lisa Pfisterer
Winter 2013: Semantic Analysis und Classification of Digital Image Streams
Elina Zarisheva, Markus Hinsche, Marcel Pursche, Hannes Würfel, Christoph Oehlke, Maximilian Schneider

PhD Students Mentoring:

Sumit Shekhar, Real-time Image and Video Analytics
Andreas Fricke, Concept and Techniques for Processing Multidimensional Geospatial Data
Willy Scheibel, Understanding Evolution of Hierarchies using Space-restricted Visualizations
Vladeta Stojanovic, Interactive Visualization for Building Lifecycle Management using BIM
Jan Ole Vollmer, Tools and Techniuqes for Visualization of High-dimensional Data

Professional Activities

Peer-Reviewing Activities for Journals:

Peer-Reviewing Activities for Conferences:

Annual Conference of the European Association for Computer Graphics (EG): 2012, 2017
EG/VGTC Conference on Visualization (EuroVis): 2014
IEEE Information Visualization (Vis): 2009
Symposium on Service-Oriented Mapping (SOMAP): 2012
ACM International Conference on 3D Web Technology (Web3D): 2014
International Conference on Computer Graphics, Visualization and Computer Vision (WSCG): 2011, 2012, 2013, 2016,

Memberships:

Other Activities:

Conference Session Chair (Rendering), GRAPP 2009/2015

Conference Talks

2019

Occlusion Management Techniques for the Visualization of Transportation Networks in Virtual 3D City Models, 12th International Symposium on Visual Information Communication and Interaction, September, Shanghai, China
Web-based Visualization of Transportation Networks for Mobility Analytics, 12th International Symposium on Visual Information Communication and Interaction, September, Shanghai, China
Semantic-driven Visualization Techniques for Interactive Exploration of 3D Indoor Models, 23rd International Conference on Information Visualization, July, Paris, France
Interactive Close-Up Rendering for Detail+Overview Visualization of 3D Digital Terrain Models, 23rd International Conference on Information Visualization, July, Paris, France
Real-time Screen-space Geometry Draping for Digital Terrain Models, 23rd International Conference on Information Visualization, July, Paris, France
Techniques for GPU-based Color Quantization, 27th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision, May, Plzen, Czech Republic

2015

Interactive Rendering and Stylization of Transportation Networks Using Distance Fields, 10th International Conference of Computer Graphics Theory and Applications, March, Berlin, Germany
Geometry Batching Using Texture-Arrays, 10th International Conference of Computer Graphics Theory and Applications, March, Berlin, Germany

2013

Interactive Projective Texturing for Non-Photorealistic Shading of Technical 3D Models, 11th TPCG 2013, September, Bath/UK
2.5D Clip-Surfaces for Technical Visualization, 21th International Conference in Central Europe on Computer Graphics, 2013, June, Plsen/Czech Republic
Interactive Rendering of Complex 3D-Treemaps, 8th International Conference of Computer Graphics Theory and Applications, February, Barcelona/Spain

2011

Integration von Fachinformationen in 3D-Darstellungen, Xinnovations 2011, E-City Forum, September, Berlin/Germany
Colonia3D, Kultur und Informatik - Multimediale Systeme, May 2011, Berlin/Germany

2010

Communication of Digital Cultural Heritage in Public Spaces by the Example of Roman Cologne, EuroMed 2010, November, Limassol/Cyprus (Best-Paper Award)
Interactive Rendering Techniques for Highlighting in 3D Geovirtual Environments, 3DGeoInfo 2010, Berlin/Germany
Interaktive 3D-Linsen für die Fokus- und Kontext-Visualisierung von generalisierten virtuellen Stadtmodellen, Deutscher Kartographentag (DKT2010), June, Berlin/Germany
Interactive Rendering to View-Dependent Texture-Atlases, Eurographics conference, May, Norrköping/Sweden

2009

Strategies for Visualizing Points-of-Interest of 3D Virtual Environments on Mobile Devices, 6th International Symposium on LBS and Telecartography, September, Nottingham/England
Enhancing Interactive Non-Planar Projections of 3D Geovirtual Environments with Stereoscopic Imaging, 1st International Conference on True-3D in Cartography, August, Dresden/Germany
Dynamic Mapping of Raster-Data for 3D Geovirtual Environments, 13th International Conference on Information Visualization, July, Barcelona/Spain
Visualization of Roman Cologne, fmx/09, May, Stuttgart/Germany
Interactive Stereo Rendering For Non-Planar Projections of 3D Virtual Environments, 4th International Conference of Computer Graphics Theory and Applications, February, Lisboa/Portugal

2008

Relief Clipping Planes for Real-Time Rendering, 1st SIGGRAPH Asia Conference, December, Singapore
3D Generalization Lenses for Interactive Focus + Context Visualization of Virtual City Models, 12th International Conference on Information Visualization, July, London
Efficient Representation of Layered Depth Images for Real-time Volumetric Tests, 6th Theory and Practice of Computer Graphics 2008 Conference, June, Manchester/UK
Interactive Multiperspective Views of Virtual 3D Landscape and City Models, 11th AGILE conference, May, Gerona/Spain (Best Paper Award)
Real-Time Volumetric Tests Using Layered Depth Images, Eurographics conference, April, Crete/Greece
A Generalization Approach for 3D Viewing Deformations of Single-Center Projections, 3rd International Conference of Computer Graphics Theory and Applications, January, Funchal/Madeira

2007

A Concept of Effective Landmark Depiction in Geovirtual 3D Environments by View-Dependent Deformation, 4th International Symposium on LBS and Telecartography, October, Hong Kong
Automated Combination of Real-Time Shader Programs, Eurographics conference, September, Prague, Czech Republic

2005

Evolutionary Algorithms - An Introduction, Stanislaw Lem Workshop on Evolution, October, Lviv (Lemberg), Ukraine

Invited Talks

Visualization Techniques for Massive Datasets, Invited Talk at the Hasso Plattner Institute, Faculty of Digital Engineering, University of Potsdam, 2017
Programmable Rendering Pipelines for Interactive Visualization, Invited Talk at the Department of Computer Graphics, Institute for Computer Science, Rostock/Germany, 2014
Neighborhood Visualization – Challenges and Approaches from a Geovisualization Perspective, Blankensee Colloquium 2012: Neighborhood Technologies Media and Mathematics of Dynamic Networks, Berlin/Germany
Colonia3D – Potenziale interaktiver Kommunikation von digitaler Denkmalpflege in öffentlichen Räumen, Prometheus Conference 2011, University of Cologne, Cologne/Germany
Kommunikation von digitaler Denkmalpflege in öffentlichen Räumen am Beispiel des Projektes Colonia3D, Invited Talk at the Department of Photogrammetry & Laserscanning at the HCU (HafenCity University), Hamburg/ Germany
High-Level Vector Editing, Invited Talk at the Computer Science Department of the Courant Institute of Mathematical Sciences at New York University, New York/USA, 2010

Awards & Miscellaneous

Best Paper Award, Web3D 2019 Conference, Classification of Indoor Point Clouds Using Multiviews
Best Paper Award, Cyberworlds 2018 Conference, MaeSTrO: A Mobile App for Style Transfer Orchestration using Neural Networks
Best Paper Award, Symposium of Mobile Graphics and Applications, SIGGRAPH Asia Conference 2017, ProsumerFX: Mobile Design of Image Stylization Components
Cover Image Selection, Proceedings of TPCG 2013
Cover Image Selection, International Journal of Heritage in the Digital Era, vol. 1, no. 1, 2012.
Cover Image Selection, gis.SCIENCE Journal, vol. 25, no. 1, 2012
Best Paper Award, EuroMed 2010 Conference, Communication of Digital Cultural Heritage in Public Spaces by the Example of Roman Cologne
Best Paper Selection, LBS & Telecartography Conference 2009, Strategies for Visualizing Points-of-Interest of 3D Virtual Environments on Mobile Devices
Best Paper Award, AGILE 2008 Conference 2008, Interactive Multi-Perspective Views of Virtual 3D Landscape and City Models
Best Paper Selection, GRAPP 2008 Conference, Generalization Approach for 3D Viewing Deformations of Single-Center Projections