@mastersthesis{Kellner-2021-DA, title = "Klassifikation Urbaner Punktwolken Mittels 3D CNNs In Kombination mit Rekonstruktion von Gehsteigen", author = "Lisa-Maria Kellner", year = "2021", abstract = "LiDAR devices are able to capture the physical world very accurately. Therefore, they are often used for 3D reconstruction. Unfortunately, such data can become extremely large very quickly and usually only a small part of the point cloud is of interest. Thus, the point cloud is filtered beforehand in order to apply algorithms only on those points that are relevant for it. A semantic information about the points can be used for such a filtering. Semantic segmentation of point clouds is a popular field of research and here there has been a trend towards deep learning in recent years too. However, contrary to images, point clouds are unstructured. Hence, point clouds are often rasterized, but this has to be done, such that the underlying structure is represented well. In this thesis, a 3D Convolutional Neural Network is developed and trained for a semantic segmentation of LiDAR point clouds. Thereby, a point cloud is represented with an octree data structure, which makes it easy to rasterize only relevant parts. Since, just dense parts of the point cloud, in which important information about the structure is located, are subdivided further. This allows to simply take nodes of a certain level of the octree and rasterize them as data samples. There are many application areas for 3D reconstructions based on point clouds. In an urban scenario, these can be for example whole city models or buildings. However, in this thesis, the reconstruction of sidewalks is explored. Since, for flood simulations in cities, an increase in height of a few centimeters can make a great difference and information about the curb geometry helps to make them more accurate. In the sidewalk reconstruction process, the point cloud is filtered first, based on a semantic segmentation of a 3D CNN, and then point cloud features are calculated to detect curb points. With these curb points, the geometry of the curb, sidewalk and street are computed. Taken all together, this thesis develops a proof-of-concept prototype for semantic point cloud segmentation using 3D CNNs and based on that, a curb detection and reconstruction algorithm.", month = mar, note = "1", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Research Unit of Computer Graphics, Institute of Visual Computing and Human-Centered Technology, Faculty of Informatics, TU Wien", URL = "https://www.cg.tuwien.ac.at/research/publications/2021/Kellner-2021-DA/", } @article{luksch_2020, title = "Real-Time Approximation of Photometric Polygonal Lights", author = "Christian Luksch and Lukas Prost and Michael Wimmer", year = "2020", abstract = "We present a real-time rendering technique for photometric polygonal lights. Our method uses a numerical integration technique based on a triangulation to calculate noise-free diffuse shading. We include a dynamic point in the triangulation that provides a continuous near-field illumination resembling the shape of the light emitter and its characteristics. We evaluate the accuracy of our approach with a diverse selection of photometric measurement data sets in a comprehensive benchmark framework. Furthermore, we provide an extension for specular reflection on surfaces with arbitrary roughness that facilitates the use of existing real-time shading techniques. Our technique is easy to integrate into real-time rendering systems and extends the range of possible applications with photometric area lights.", month = may, journal = "Proceedings of the ACM on Computer Graphics and Interactive Techniques", volume = "3", number = "1", issn = "2577-6193", doi = "10.1145/3384537", pages = "4.1--4.18", keywords = "area lights, photometric lights, real-time rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2020/luksch_2020/", } @mastersthesis{Pfahler-2016-MT, title = "Visualisierung hochdimensionaler Daten mit hierarchischer Gruppierung von Teilmengen", author = "David Pfahler", year = "2019", abstract = "The number of installed sensors to acquire data, for example electricity meters in smart grids, is increasing rapidly. The huge amount of collected data needs to be analyzed and monitored by transmission-system operators. This task is supported by visual analytics techniques, but traditional multi-dimensional data visualization techniques do not scale very well for high-dimensional data. The main contribution of this thesis is a framework to efficiently examine and compare such high-dimensional data. The key idea is to divide the data by the semantics of the underlying dimensions into groups. Domain experts are familiar with the meta-information of the data and are able to structure these groups into a hierarchy. Various statistical properties are calculated from the subdivided data. These are then visualized by the proposed system using appropriate means. The hierarchy and the visualizations of the calculated statistical values are displayed in a tabular layout. The rows contain the subdivided data and the columns visualize their statistics. Flexible interaction possibilities with the visual representation help the experts to fulfill their analysis tasks. The tasks include searching for structures, sorting by statistical properties, identifying correlations of the subdivided data, and interactively subdivide or combine the data. A usage scenario evaluates the design of the framework with a data set of the target domain in the energy sector.", month = oct, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Research Unit of Computer Graphics, Institute of Visual Computing and Human-Centered Technology, Faculty of Informatics, TU Wien", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/Pfahler-2016-MT/", } @article{CORNEL-2019-IVF, title = "Interactive Visualization of Flood and Heavy Rain Simulations", author = "Daniel Cornel and Andreas Buttinger-Kreuzhuber and Artem Konev and Zsolt Horvath and Michael Wimmer and Raimund Heidrich and J\"{u}rgen Waser", year = "2019", abstract = "In this paper, we present a real-time technique to visualize large-scale adaptive height fields withC1-continuous surfacereconstruction. Grid-based shallow water simulation is an indispensable tool for interactive flood management applications.Height fields defined on adaptive grids are often the only viable option to store and process the massive simulation data. Theirvisualization requires the reconstruction of a continuous surface from the spatially discrete simulation data. For regular grids,fast linear and cubic interpolation are commonly used for surface reconstruction. For adaptive grids, however, there exists nohigher-order interpolation technique fast enough for interactive applications.Our proposed technique bridges the gap between fast linear and expensive higher-order interpolation for adaptive surfacereconstruction. During reconstruction, no matter if regular or adaptive, discretization and interpolation artifacts can occur,which domain experts consider misleading and unaesthetic. We take into account boundary conditions to eliminate these artifacts,which include water climbing uphill, diving towards walls, and leaking through thin objects. We apply realistic water shadingwith visual cues for depth perception and add waves and foam synthesized from the simulation data to emphasize flow directions.The versatility and performance of our technique are demonstrated in various real-world scenarios. A survey conducted withdomain experts of different backgrounds and concerned citizens proves the usefulness and effectiveness of our technique.", month = jun, journal = "Computer Graphics Forum", volume = "38", number = "3", issn = "1467-8659", doi = "10.1111/cgf.13669", pages = "25--39", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/CORNEL-2019-IVF/", } @inproceedings{STEINLECHNER-2019-APS, title = "Adaptive Point-cloud Segmentation for Assisted Interactions", author = "Harald Steinlechner and Bernhard Rainer and Michael Schw\"{a}rzler and Georg Haaser and Attila Szabo and Stefan Maierhofer and Michael Wimmer", year = "2019", abstract = "In this work, we propose an interaction-driven approach streamlined to support and improve a wide range of real-time 2D interaction metaphors for arbitrarily large pointclouds based on detected primitive shapes. Rather than performing shape detection as a costly pre-processing step on the entire point cloud at once, a user-controlled interaction determines the region that is to be segmented next. By keeping the size of the region and the number of points small, the algorithm produces meaningful results and therefore feedback on the local geometry within a fraction of a second. We can apply these finding for improved picking and selection metaphors in large point clouds, and propose further novel shape-assisted interactions that utilize this local semantic information to improve the user’s workflow.", month = may, isbn = "978-1-4503-6310-5", series = "I3D ’19", publisher = "ACM", location = "Montreal, Quebec, Canada", event = "33rd Symposium on Interactive 3D Graphics and Games", editor = "Blenkhorn, Ari Rapkin", doi = "10.1145/3306131.3317023", booktitle = "Proceedings of the 33rd Symposium on Interactive 3D Graphics and Games", pages = "14:1--14:9", keywords = "Pointcloud Segmentation, Shape Detection, Interactive Editing", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/STEINLECHNER-2019-APS/", } @inproceedings{LUKSCH-2019-IGI, title = "Incrementally Baked Global Illumination", author = "Christian Luksch and Michael Wimmer and Michael Schw\"{a}rzler", year = "2019", abstract = "Global Illumination is affected by the slightest change in a 3D scene, requiring a complete reevaluation of the distributed light. In cases where real-time algorithms are not applicable due to high demands on the achievable accuracy, this recomputation from scratch results in artifacts like flickering or noise, disturbing the visual appearance and negatively affecting interactive lighting design workflows. We propose a novel system tackling this problem by providing incremental updates of a baked global illumination solution after scene modifications, and a re-convergence after a few seconds. Using specifically targeted incremental data structures and prioritization strategies in a many-light global illumination algorithm, we compute a differential update from one illumination state to another. We further demonstrate the use of a novel error balancing strategy making it possible to prioritize the illumination updates.", month = may, isbn = "978-1-4503-6310-5", series = "I3D ’19", publisher = "ACM", location = "Montreal, Quebec, Canada", event = "33rd Symposium on Interactive 3D Graphics and Games (I3D 2019)", editor = "Blenkhorn, Ari Rapkin", doi = "10.1145/3306131.3317015", booktitle = "Proceedings of the 33rd Symposium on Interactive 3D Graphics and Games (I3D 2019)", pages = "4:1--4:10", keywords = "Global Illumination, Instant Radiosity, Lightmaps", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/LUKSCH-2019-IGI/", } @inproceedings{kroesl-2019-ICthroughVR, title = "ICthroughVR: Illuminating Cataracts through Virtual Reality", author = "Katharina Kr\"{o}sl and Carmine Elvezio and Matthias H\"{u}rbe and Sonja Karst and Michael Wimmer and Steven Feiner", year = "2019", abstract = "Vision impairments, such as cataracts, affect how many people interact with their environment, yet are rarely considered by architects and lighting designers because of a lack of design tools. To address this, we present a method to simulate vision impairments caused by cataracts in virtual reality (VR), using eye tracking for gaze-dependent effects. We conducted a user study to investigate how lighting affects visual perception for users with cataracts. Unlike past approaches, we account for the user's vision and some constraints of VR headsets, allowing for calibration of our simulation to the same level of degraded vision for all participants.", month = mar, publisher = "IEEE", location = "Osaka, Japan", event = "IEEE VR 2019, the 26th IEEE Conference on Virtual Reality and 3D User Interfaces", doi = "10.1109/VR.2019.8798239", booktitle = "2019 IEEE Conference on Virtual Reality and 3D User Interfaces", pages = "655--663", keywords = "vision impairments, cataracts, virtual reality, user study", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/kroesl-2019-ICthroughVR/", } @inproceedings{schuetz-2019-CLOD, title = "Real-Time Continuous Level of Detail Rendering of Point Clouds", author = "Markus Sch\"{u}tz and Katharina Kr\"{o}sl and Michael Wimmer", year = "2019", abstract = "Real-time rendering of large point clouds requires acceleration structures that reduce the number of points drawn on screen. State-of-the art algorithms group and render points in hierarchically organized chunks with varying extent and density, which results in sudden changes of density from one level of detail to another, as well as noticeable popping artifacts when additional chunks are blended in or out. These popping artifacts are especially noticeable at lower levels of detail, and consequently in virtual reality, where high performance requirements impose a reduction in detail. We propose a continuous level-of-detail method that exhibits gradual rather than sudden changes in density. Our method continuously recreates a down-sampled vertex buffer from the full point cloud, based on camera orientation, position, and distance to the camera, in a point-wise rather than chunk-wise fashion and at speeds up to 17 million points per millisecond. As a result, additional details are blended in or out in a less noticeable and significantly less irritating manner as compared to the state of the art. The improved acceptance of our method was successfully evaluated in a user study.", month = mar, publisher = "IEEE", location = "Osaka, Japan", event = "IEEE VR 2019, the 26th IEEE Conference on Virtual Reality and 3D User Interfaces", doi = "10.1109/VR.2019.8798284", booktitle = "2019 IEEE Conference on Virtual Reality and 3D User Interfaces", pages = "103--110", keywords = "point clouds, virtual reality, VR", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/schuetz-2019-CLOD/", } @inproceedings{STEINLECHNER-2019-ICT, title = "A Novel Approach for Immediate, Interactive CT Data Visualization andEvaluation using GPU-based Segmentation and Visual Analysis", author = "Harald Steinlechner and Georg Haaser and Bernd Oberdorfer and Daniel Habe and Stefan Maierhofer and Michael Schw\"{a}rzler and Eduard Gr\"{o}ller", year = "2019", abstract = "CT data of industrially produced cast metal parts are often afflicted with artefacts due to complex geometries ill-suited for the scanning process. Simple global threshold-based porosity detection algorithms usually fail to deliver meaningful results. Other adaptive methods can handle image artefacts, but require long preprocessing times. This makes an efficient analysis workflow infeasible. We propose an alternative approach for analyzing and visualizing volume defects in a fully interactive manner, where analyzing volumes becomes more of an interactive exploration instead of time-consuming parameter guessing interrupted by long processing times. Our system is based on a highly efficient GPU implementation of a segmentation algorithm for porosity detection. The runtime is on the order of seconds for a full volume and parametrization is kept simple due to a single threshold parameter. A fully interactive user interface comprised of multiple linked views allows to quickly identify defects of interest, while filtering out artefacts even in noisy areas.", month = feb, location = "Padova, Italy", event = "International Conference on Industrial Computed Tomography (ICT) 2019", editor = "Simone Carmignato", booktitle = "International Conference on Industrial Computed Tomography (ICT) 2019", pages = "1--6", keywords = "CT, GPU, Inclusion Detection, Interactive Visualisation, VisualAnalysis, Parallel Coordinates, Volume Rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/STEINLECHNER-2019-ICT/", } @mastersthesis{PROST-2019-RTPAL, title = "Real-Time Photometric Area Light Approximation for Interactive Lighting Design", author = "Lukas Prost", year = "2019", abstract = "Photometric light sources are modeled after real-world luminaires and are used in lighting design to accurately simulate lighting. While an accurate evaluation of their illumination is possible with offline global-illumination algorithms, currently used realtime approximations, which are required for an interactive lighting design work flow, are prone to errors when the light source is close to illuminated objects. This is due to the non-zero dimensionality of photometric lights, which are often area or volume lights. In this thesis, we present a new technique to approximate photometric area lights in real time. This new technique is based on combining two sampling strategies that are currently used in game engines to approximate the illumination from diffuse area lights. Our technique samples the photometric area light with this combined sampling strategy and then computes the illumination with a cubature technique based the Delaunay triangulation. To do this in real time, we implemented our method on the GPU and developed a compact triangle data structure that enables an efficient generation of a Delaunay triangulation. The result of this thesis is a new technique for photometric area lights that creates visually plausible approximations in real time, even if the light source is close to illuminated objects.", month = feb, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Research Unit of Computer Graphics, Institute of Visual Computing and Human-Centered Technology, Faculty of Informatics, TU Wien", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/PROST-2019-RTPAL/", } @mastersthesis{donabauer_2019_1, title = "VR-Client for Scenario-based Response Training in Disaster Management", author = "Johanna Donabauer", year = "2019", abstract = "In times of natural disasters like floods, the fast action of domain experts saves human lives and reduces high damages of the urban infrastructure. The training of different response plans of the responsible personnel should help in making the right decisions in time critical situations. As the creation of various physical training environments takes plenty of time, the use of virtual reality (VR) is a possible alternative. In recent years, different application domains with training purpose have been shifted to make use of the new developments in the field of VR. The desired benefits are a more flexible generation of different realistic training environments with low budget and material resources. Additionally, the VR application can serve as a public communication tool to raise the sense of awareness. Based on these considerations, the aim of this work is to create a VR training application to steer a remote flood simulation. The goal of the application is to provide a safe and realistic environment to train the responsible personnel. Through providing different scenarios, multiple flood events can be simulated and trained. The placement of barriers through interacting with the virtual environment offers possibilities to mitigate the results of the simulated floods. An Operator-Trainee setup enables the collaborative work between experts and trainees. While the expert works as an operator with a PC client, the trainee is able to perform instructions given by the operator within the virtual environment. VR applications demand for high and steady frame rates as well as two high resolution images for both eyes to provide an immersive VR experience. Based on these conditions, appropriate PC hardware is needed to run a VR application in general. Additionally, high computational power is needed to perform the different flood simulations in a fast way. In order to achieve the performance requirements, the VR application is implemented within a client-server architecture. The server is responsible for performing the flood simulation, while the client deals with the VR-related tasks. These tasks comprise the visualization of the simulation data in VR and a fast and efficient processing of the data. In combination with a high performance rendering engine and graphic commands suitable for the given data, the desired performance can be achieved. As the feeling of immersion is highly depending on the provided frame rates, the evaluation of this first prototype is based on the achieved rendering performance. This is measured and evaluated based on two different implementation strategies. Another important measurement is the update time of the water flow. A comparison of a CPU and a GPU implementation is presented within the evaluation.", month = jan, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Research Unit of Computer Graphics, Institute of Visual Computing and Human-Centered Technology, Faculty of Informatics, TU Wien", URL = "https://www.cg.tuwien.ac.at/research/publications/2019/donabauer_2019_1/", } @mastersthesis{ludwig-2012-MT, title = "Radial Diagrams for the Visual Analysis of Wind Energy Production Data", author = "Wolfgang Ludwig", year = "2018", abstract = "Wind energy production is a fast growing sector in the field of renewable energy production. In the process of energy production, more and more data is produced and recorded every year. This data is usually worthless without further exploration, analysis, and presentation. This thesis presents a design study of the visual analysis of wind energy production data. The goal is to provide data analysts with tools to carry out common tasks in the field of wind energy production more efficiently. As the data commonly contains directional information of winds and gusts, analysis techniques need to take the circular nature of such data into account. This work proposes a set of techniques for the visualization and interaction with circular data in radial diagrams. The diagrams operate in the polar coordinate system and thus are well suited to solve the problems of maintaining the natural coherence and circular closure of circular data. The thesis discusses important design decisions and gives practical guidance how to implement novel features into an existing software system. Implementation details on how to ensure large data scalability are presented. The work evaluates the results in a case study with real data carried out by an expert in the field of wind energy production. The results indicate an improved work flow of common tasks and a successful system integration. The reported deployment at a national power grid operator further demonstrates the system’s user acceptance and importance. The thesis also reflects on the iterative design process and the within collected expert feedback.", month = oct, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/ludwig-2012-MT/", } @inproceedings{kroesl-2018-DC, title = "[DC] Computational Design of Smart Lighting Systems for Visually Impaired People, using VR and AR Simulations", author = "Katharina Kr\"{o}sl", year = "2018", abstract = "This Doctoral Consortium paper presents my dissertation research in a multidisciplinary setting, spanning over the areas of architecture, specifically lighting design and building information modeling, to virtual reality (VR) and perception. Since vision impairments are hardly taken into account in architecture and lighting design today, this research aims to provide the necessary tools to quantify the effects of vision impairments, so design guidelines regarding these impairments can be developed. Another research goal is the determination of the influence of different lighting conditions on the perception of people with vision impairments. This would allow us to develop smart lighting systems that can aid visually impaired people by increasing their visual perception of their environment. This paper also outlines the concept for a tool to automatically generate lighting solutions and compare and test them in VR, as design aid for architects and lighting designers.", month = oct, publisher = "IEEE", location = "Munich", event = "ISMAR 2018", booktitle = "Proceedings of the 2018 IEEE International Symposium on Mixed and Augmented Reality (ISMAR-Adjunct)", keywords = "vision impairments, lighting design, virtual reality, user study", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/kroesl-2018-DC/", } @article{Konev-FCV2018, title = "Fast cutaway visualization of sub-terrain tubular networks", author = "Artem Konev and Manuel Matusich and Ivan Viola and Hendrik Schulze and Daniel Cornel and J\"{u}rgen Waser", year = "2018", month = oct, doi = "https://doi.org/10.1016/j.cag.2018.07.004", issn = "0097-8493", journal = "Computers & Graphics", number = "5", pages = "25–35", volume = "75", pages = "25--35", keywords = "Cutaway visualization, Procedural billboarding, Subsurface networks", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/Konev-FCV2018/", } @phdthesis{Muehlbacher_diss_2018, title = "Human-Oriented Statistical Modeling: Making Algorithms Accessible through Interactive Visualization", author = "Thomas M\"{u}hlbacher", year = "2018", abstract = "Statistical modeling is a key technology for generating business value from data. While the number of available algorithms and the need for them is growing, the number of people with the skills to effectively use such methods lags behind. Many application domain experts find it hard to use and trust algorithms that come as black boxes with insufficient interfaces to adapt. The field of Visual Analytics aims to solve this problem by a human-oriented approach that puts users in control of algorithms through interactive visual interfaces. However, designing accessible solutions for a broad set of users while re-using existing, proven algorithms poses significant challenges for the design of analytical infrastructures, visualizations, and interactions. This thesis provides multiple contributions towards a more human-oriented modeling process: As a theoretical basis, it investigates how user involvement during the execution of algorithms can be realized from a technical perspective. Based on a characterization of needs regarding intermediate feedback and control, a set of formal strategies to realize user involvement in algorithms with different characteristics is presented. Guidelines for the design of algorithmic APIs are identified, and requirements for the re-use of algorithms are discussed. From a survey of frequently used algorithms within R, the thesis concludes that a range of pragmatic options for enabling user involvement in new and existing algorithms exist and should be used. After these conceptual considerations, the thesis presents two methodological contributions that demonstrate how even inexperienced modelers can be effectively involved in the modeling process. First, a new technique called TreePOD guides the selection of decision trees along trade-offs between accuracy and other objectives, such as interpretability. Users can interactively explore a diverse set of candidate models generated by sampling the parameters of tree construction algorithms. Visualizations provide an overview of possible tree characteristics and guide model selection, while details on the underlying machine learning process are only exposed on demand. Real-world evaluation with domain experts in the energy sector suggests that TreePOD enables users with and without statistical background a confident identification of suitable decision trees. As the second methodological contribution, the thesis presents a framework for interactive building and validation of regression models. The framework addresses limitations of automated regression algorithms regarding the incorporation of domain knowledge, identifying local dependencies, and building trust in the models. Candidate variables for model refinement are ranked, and their relationship with the target variable is visualized to support an interactive workflow of building regression models. A real-world case study and feedback from domain experts in the energy sector indicate a significant effort reduction and increased transparency of the modeling process. All methodological contributions of this work were implemented as part of a commercially distributed Visual Analytics software called Visplore. As the last contribution, this thesis reflects upon years of experience in deploying Visplore for modeling-related tasks in the energy sector. Dissemination and adoption are important aspects of making statistical models more accessible for domain experts, making this work relevant for practitioners and application-oriented researchers alike.", month = aug, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/Muehlbacher_diss_2018/", } @misc{kroesl-2018-TVS, title = "The Virtual Schoolyard: Attention Training in Virtual Reality for Children with Attentional Disorders", author = "Katharina Kr\"{o}sl and Anna Felnhofer and Johanna X. Kafka and Laura Schuster and Alexandra Rinnerthaler and Michael Wimmer and Oswald D. Kothgassner", year = "2018", abstract = "This work presents a virtual reality simulation for training different attentional abilities in children and adolescents. In an interdisciplinary project between psychology and computer science, we developed four mini-games that are used during therapy sessions to battle different aspects of attentional disorders. First experiments show that the immersive game-like application is well received by children. Our tool is also currently part of a treatment program in an ongoing clinical study.", month = aug, publisher = "ACM", location = "Vancouver, Canada", isbn = "978-1-4503-5817-0", event = "ACM SIGGRAPH 2018", doi = "10.1145/3230744.3230817", Conference date = "Poster presented at ACM SIGGRAPH 2018 (2018-08-12--2018-08-16)", note = "Article 27--", pages = "Article 27 – ", keywords = "virtual reality, attentional disorders, user study", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/kroesl-2018-TVS/", } @phdthesis{schwaerzler_2018_phd, title = "Advances in the Multimodal 3D Reconstruction and Modeling of Buildings", author = "Michael Schw\"{a}rzler", year = "2018", abstract = "Driven by the need for faster and more efficient workflows in the digitization of urban environments, the availability of affordable 3D data-acquisition systems for buildings has drastically increased in the last years: Laser scanners and photogrammetric methods both produce millions of 3D points within minutes of acquisition time. They are applied both on street-level as well as from above using drones, and are used to enhance traditional tachymetric measurements in surveying. However, these 3D data points are not the only available information: Extracted meta data from images, simulation results (e.g., from light simulations), 2D floor plans, and semantic tags – especially from the upcoming Building Information Modeling (BIM) systems – are becoming increasingly important. The challenges this multimodality poses during the reconstruction of CAD-ready 3D buildings are manifold: Apart from handling the enormous size of the data that is collected during the acquisition steps, the different data sources must also be registered to each other in order to be applicable in a common context – which can be difficult in case of missing or erroneous information. Nevertheless, the potential for improving both the workflow efficiency as well as the quality of the reconstruction results is huge: Missing information can be substituted by data from other sources, information about spatial or semantic relations can be utilized to overcome limitations, and interactive modeling complexity can be reduced (e.g., by limiting interactions to a two-dimensional space). In this thesis, four publications are presented which aim at providing freely combinable “building blocks” for the creation of helpful methods and tools for advancing the field of Multimodal Urban Reconstruction. First, efficient methods for the calculation of shadows cast by area light sources are presented – one with a focus on the most efficient generation of physically accurate penumbras, and the other one with the goal of reusing soft shadow information in consecutive frames to avoid costly recalculations. Then, a novel, optimization-supported reconstruction and modeling tool is presented, which employs sketch-based interactions and snapping techniques to create water-tight 3D building models. An extension to this system is demonstrated consecutively: There, 2D photos act as the only interaction canvas for the simple, sketch-based creation of building geometry and the corresponding textures. Together, these methods form a solid foundation for the creation of common, multimodal environments targeted at the reconstruction of 3D building models.", month = jun, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/schwaerzler_2018_phd/", } @article{Kathi-2018-VRB, title = "A VR-based user study on the effects of vision impairments on recognition distances of escape-route signs in buildings", author = "Katharina Kr\"{o}sl and Dominik Bauer and Michael Schw\"{a}rzler and Henry Fuchs and Michael Wimmer and Georg Suter", year = "2018", abstract = "In workplaces or publicly accessible buildings, escape routes are signposted according to official norms or international standards that specify distances, angles and areas of interest for the positioning of escape-route signs. In homes for the elderly, in which the residents commonly have degraded mobility and suffer from vision impairments caused by age or eye diseases, the specifications of current norms and standards may be insufficient. Quantifying the effect of symptoms of vision impairments like reduced visual acuity on recognition distances is challenging, as it is cumbersome to find a large number of user study participants who suffer from exactly the same form of vision impairments. Hence, we propose a new methodology for such user studies: By conducting a user study in virtual reality (VR), we are able to use participants with normal or corrected sight and simulate vision impairments graphically. The use of standardized medical eyesight tests in VR allows us to calibrate the visual acuity of all our participants to the same level, taking their respective visual acuity into account. Since we primarily focus on homes for the elderly, we accounted for their often limited mobility by implementing a wheelchair simulation for our VR application.", month = apr, journal = "The Visual Computer", volume = "34", number = "6-8", issn = "0178-2789", doi = "10.1007/s00371-018-1517-7", pages = "911--923", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/Kathi-2018-VRB/", } @WorkshopTalk{Purgathofer-2018-EG, title = "Best Practice in Technology Transfer", author = "Werner Purgathofer", year = "2018", month = apr, event = "Eurographics Industrial Presentations", location = "Delft, NL", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/Purgathofer-2018-EG/", } @bachelorsthesis{Cai_2018, title = "Research on Graphical Interfaces to Perform Anatomical Queries on Large Collections of Gene Expression Images", author = "Yan Cai", year = "2018", abstract = "As image information is increasing sharply, searching and presenting interesting images in large databases have become more and more important in image management. In this paper, an optimizing graphical query interface was designed for anatomical search to present more valuable information from the large neuro-anatomical image collections of Drosophila (fruit fly) brains. In order to achieve the goal, the relevant websites of “Fly Circuit”, “Fly Light” and “Allen Mouse Brain Atlas”, and the image management software of PivotViewer and Zegami were investigated firstly. Then, analysis and comparison for the mentioned tools using different perspectives were conducted to define the guidelines for best practices out of them. Based on the findings, several redesigns are proposed for neuro-anatomical query interfaces and part of them were implemented. ", month = apr, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/Cai_2018/", } @inproceedings{PB-VRVis-2018-005, title = "An Automated Verification Workflow for Planned Lighting Setups using BIM", author = "Andreas Walch and Katharina Kr\"{o}sl and Christian Luksch and David Pichler and Thomas Pipp and Michael Schw\"{a}rzler", year = "2018", abstract = "The use of Building Information Modeling (BIM) methods is becoming more and more established in the planning stage, during the construction, and for the management of buildings. Tailored BIM software packages allow to handle a vast amount of relevant aspects, but have so far not been covering specialized tasks like the evaluation of light distributions in and around a 3D model of a building. To overcome this limitation, we demonstrate the use of the open-source IFC format for preparing and exchanging BIM data to be used in our interactive light simulation system. By exploiting the availability of 3D data and semantic descriptions, it is possible to automatically place measurement surfaces in the 3D scene, and evaluate the suitability and sustainability of a planned lighting design according to given constraints and industry norms. Interactive visualizations for fast analysis of the simulation results, created using state-of-the-art web technologies, are seamlessly integrated in the 3D work environment, helping the lighting designer to quickly improve the initial lighting solution with a few clicks.", month = apr, isbn = "978-3-9504173-5-7", series = "REAL CORP", event = "REAL CORP 2018", editor = "M. Schrenk and V. V. Popovich and P. Zeile and P. Elisei and C. Beyerand G. Navratil", booktitle = "REAL CORP 2018, Proceedings", pages = "55–65", pages = "55--65", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/PB-VRVis-2018-005/", } @article{Reichinger-2018-TAC, title = "Pictures in Your Mind: Using Interactive Gesture-Controlled Reliefs to Explore Art", author = "Andreas Reichinger and H. G. Carrizosa and J. Wood and S. Schr\"{o}der and C. L\"{o}w and Laura R. Luidolt and Maria Schimkowitsch and Anton Fuhrmann and Stefan Maierhofer and Werner Purgathofer", year = "2018", abstract = "Tactile reliefs offer many benefits over the more classic raised line drawings or tactile diagrams, as depth, 3D shape, and surface textures are directly perceivable. Although often created for blind and visually impaired (BVI) people, a wider range of people may benefit from such multimodal material. However, some reliefs are still difficult to understand without proper guidance or accompanying verbal descriptions, hindering autonomous exploration. In this work, we present a gesture-controlled interactive audio guide (IAG) based on recent low-cost depth cameras that can be operated directly with the hands on relief surfaces during tactile exploration. The interactively explorable, location-dependent verbal and captioned descriptions promise rapid tactile accessibility to 2.5D spatial information in a home or education setting, to online resources, or as a kiosk installation at public places. We present a working prototype, discuss design decisions, and present the results of two evaluation studies: the first with 13 BVI test users and the second follow-up study with 14 test users across a wide range of people with differences and difficulties associated with perception, memory, cognition, and communication. The participant-led research method of this latter study prompted new, significant and innovative developments. ", month = mar, journal = "ACM Transactions on Accessible Computing", number = "2", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/Reichinger-2018-TAC/", } @mastersthesis{Szabo-2018-DA, title = "A Composable and Reusable Photogrammetric Reconstruction Library", author = "Attila Szabo", year = "2018", month = mar, note = "1", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/Szabo-2018-DA/", } @mastersthesis{Bauer_Dominik_2018_VR, title = "Evaluation of the Recognition Distances of Safety Signs in VR Considering Vision Impairments", author = "Dominik Bauer", year = "2018", abstract = "To facilitate the safe evacuation of buildings, escape-route safety signs need to be placed along the whole escape route such that they are legible for building occupants. While standards and legal requirements provide suggestions on how to select and place safety signs to achieve this, they do not provide sufficient considerations concerning people suffering from vision impairments. A main cause of vision impairment are age-related eye diseases, with the most common symptom being the loss of visual acuity. We investigate the influence of visual acuity on the ability to recognize safety signs using a novel methodology, evaluating existing standards concerning vision impairments: We calibrate the visual acuity of the test subjects to the same level via a standardized medical test in VR. This is achieved by using test subjects with normal or corrected vision and simulating the impairment in VR. Furthermore, we present a tool for lighting designers which enables them to check their designs considering maximum recognition distances to investigate problematic areas along an escape route. Using our novel user-study methodology, we determined the recognition distances for safety signs, observed under two different levels of visual acuity and varying observation angles. In addition, we determined the impact of the HTC Vive’s HMD on the visual acuity achievable in VR. We conclude that the existing standards fail to correctly estimate the maximum recognition distances of safety signs for observers suffering from reduced visual acuity.", month = feb, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "virtual reality, vision impairment simulation, emergency lighting", URL = "https://www.cg.tuwien.ac.at/research/publications/2018/Bauer_Dominik_2018_VR/", } @mastersthesis{Rainer_2017, title = "Interactive Shape Detection in Out-of-Core Point Clouds for Assisted User Interactions", author = "Bernhard Rainer", year = "2017", abstract = "This thesis presents a semi-automated method for shape detection in out-of-core point clouds. Rather than performing shape detection on the entire point cloud at once, a user-controlled interaction determines the region that is to be segmented next. By keeping the size of the region and the number of points small, the algorithm produces meaningful results within a fraction of a second. Thus, the user is presented immediately with feedback on the local geometry. As modern point clouds can contain billions of points and the memory capacity of consumer PCs is usually insufficient to hold all points in memory at the same time, a level-of-detail data structure is used to store the point cloud on the hard disc, and data is loaded into memory only on use. This data structure partitions the point cloud into small regions, each containing around 5000 points, that are used for rendering and shape detection. Interacting with point clouds is a particularly demanding task. A precise selection of a region of interest, using the two-dimensional lasso interaction, often needs multiple view changes and subsequent improvements. This thesis proposes improvements to the lasso interaction, by performing selection only on the set of points that are approximated by a detected shape. Thus, the selection of undesired points in the fore- and background is reduced. Point picking is improved as well by the use of a detected shape, such that only points that are approximated by this shape are pick-able. The result of this thesis is an application that allows the user to view point clouds with millions of points. It also provides a novel interaction technique for quick local shape detection as well as shape-assisted interactions that utilize this local semantic information to improve the user’s workflow.", month = nov, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/Rainer_2017/", } @talk{Purgathofer-2017-China2, title = "From Visualization to Decision Support", author = "Werner Purgathofer", year = "2017", month = sep, event = "2nd International Forum on VR Visual Computing Technologies", location = "Hangzhou, China", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/Purgathofer-2017-China2/", } @talk{Purgathofer-2017-China1, title = "From Visualization to Decision Support", author = "Werner Purgathofer", year = "2017", month = sep, event = "Virtual Reality and Visual Computing International Forum", location = "Nanjing, China", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/Purgathofer-2017-China1/", } @phdthesis{sorger-2017-thesis, title = "Integration Strategies in the Visualization of Multifaceted Spatial Data", author = "Johannes Sorger", year = "2017", abstract = "Visualization designers have several visual channels at their disposal for encoding data into visual representations, e.g., position, size, shape, orientation, color, texture, brightness, as well as motion. The mapping of attributes to visual channels can be chosen by the designer. In theory, any data attribute can be represented by any of these visual channels or by a combination of multiple of these channels. In practice, the optimal mapping and the most suitable type of visualization strongly depend on the data as well as on the user's task. In the visualization of spatial data, the mapping of spatial attributes to visual channels is inherently given by the data. Multifaceted spatial data possesses a wide range of additional (non-spatial) attributes without a given mapping. The data's given spatial context is often important for successfully fulfilling a task. The design space in spatial data visualization can therefore be heavily constrained when trying to choose an optimal mapping for other attributes within the spatial context. To solve an exploration or presentation task in the domain of multifaceted spatial data, special strategies have to be employed in order to integrate the essential information from the various data facets in an appropriate representation form with the spatial context. This thesis explores visualization integration strategies for multifaceted spatial data. The first part of this thesis describes the design space of integration in terms of two aspects: visual and functional integration. Visual integration describes how representations of the different data facets can be visually composed within a spatial context. Functional integration, describes how events that have been triggered, for instance, through user interaction, can be coordinated across the various visually integrated representations. The second part of this thesis describes contributions to the field of visualization in the context of concrete integration applications for exploration and presentation scenarios. The first scenario addresses a set of challenges in the exploratory analysis of multifaceted spatial data in the scope of a decision making scenario in lighting design. The user's task is to find an optimal lighting solution among dozens or even hundreds of potential candidates. In the scope of a design study, the challenges in lighting design are addressed with LiteVis, a system that integrates representations of the simulation parameter space with representations of all relevant aspects of the simulation output. The integration of these heterogeneous aspects together with a novel ranking visualization are thereby the key to enabling an efficient exploration and comparison of lighting parametrizations. In presentation scenarios, the generation of insights often cannot rely on user interaction and therefore needs a different approach. The challenge is to generate visually appealing, yet information-rich representations for mainly passive observation. In this context, this thesis addresses two different challenges in the domain of molecular visualization. The first challenge concerns the conveying of relations between two different representations of a molecular data set, such as a virus. The relation is established via animated transitions - a temporal form of integration between two representations. The proposed solution features a novel technique for creating such transitions that are re-usable for different data sets, and can be combined in a modular fashion. Another challenge in presentation scenarios of multifaceted spatial data concerns the presentation of the transition between development states of molecular models, where the actual biochemical process of the transition is not exactly known or it is too complex to represent. A novel technique applies a continuous abstraction of both model representations to a level of detail at which the relationship between them can be accurately conveyed, in order to overcome a potential indication of false relationship information. Integration thereby brings the different abstraction levels and the different model states into relation with each other. The results of this thesis clearly demonstrate that integration is a versatile tool in overcoming key challenges in the visualization of multifaceted spatial data. ", month = sep, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/sorger-2017-thesis/", } @inproceedings{kroesl-2017-LiteMaker, title = "LiteMaker: Interactive Luminaire Development using Progressive Photon Tracing and Multi-Resolution Upsampling", author = "Katharina Kr\"{o}sl and Christian Luksch and Michael Schw\"{a}rzler and Michael Wimmer", year = "2017", abstract = "Industrial applications like luminaire development (the creation of a luminaire in terms of geometry and material) or lighting design (the efficient and aesthetic placement of luminaires in a virtual scene) rely heavily on high realism and physically correct simulations. Using typical approaches like CAD modeling and offline rendering, this requirement induces long processing times and therefore inflexible workflows. In this paper, we combine a GPU-based progressive photon-tracing algorithm to accurately simulate the light distribution of a luminaire with a novel multi-resolution image-filtering approach that produces visually meaningful intermediate results of the simulation process. By using this method in a 3D modeling environment, luminaire development is turned into an interactive process, allowing for real-time modifications and immediate feedback on the light distribution. Since the simulation results converge to a physically plausible solution that can be imported as a representation of a luminaire into a light-planning software, our work contributes to combining the two former decoupled workflows of luminaire development and lighting design, reducing the overall production time and cost for luminaire manufacturers. ", month = sep, isbn = "978-3-03868-049-9", publisher = "The Eurographics Association", location = "Bonn, Germany", event = "VMV 2017", editor = "Matthias Hullin and Reinhard Klein and Thomas Schultz and Angela Yao", doi = "10.2312/vmv.20171253", booktitle = "Vision, Modeling & Visualization", pages = "1--8", keywords = "Computing methodologies, Ray tracing, Image processing, Mesh geometry models", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/kroesl-2017-LiteMaker/", } @bachelorsthesis{Zusag-2017-Bach, title = "Deep Learning Architectures for vessel Segmentation in 2D and 3D Biomedical Images", author = "Mario Zusag", year = "2017", abstract = "The aim of this thesis is to describe deep learning approaches for vessel segmentation in 2 and 3-dimensional biomedical images and the results achieved from these approaches on specific sets of data. The first chapter introduces the objective of this thesis, describes the data, which was used for the training, gives a short overview of machine learning and covers some theoretical aspects of artificial neural networks and especially of convolutional neural networks. The second chapter describes methods that were used for achieving the segmentation in 2 and 3 dimensions, like preprocessing of the images, algorithmic approaches, and general project set-up. The third and final chapter focuses on the results of methods described in chapter 2, contains personal advice for future approaches for improving the algorithm’s results and discusses the results. The thesis provides the theory, code snippets for the most fundamental part of the algorithms’ implementations and shows graphical, as well as numerical results of the approaches.", month = aug, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/Zusag-2017-Bach/", } @mastersthesis{ERLER-2017-HVR, title = "Haptic Feedback in Room-Scale VR", author = "Philipp Erler", year = "2017", abstract = "Virtual reality (VR) is now becoming a mainstream medium. Current systems like the HTC Vive offer accurate tracking of the HMD and controllers, which allows for highly immersive interactions with the virtual environment. The interactions can be further enhanced by adding feedback. As an example, a controller can vibrate when it is close to a grabbable ball. As such interactions are not exhaustingly researched, we conducted a user study. Specifically, we examine: - grabbing and throwing with controllers in a simple basketball game. - the influence of haptic and optical feedback on performance, presence, task load, and usability. - the advantages of VR over desktop for point-cloud editing. Several new techniques emerged from the point-cloud editor for VR. The bi-manual pinch gesture, which extends the handlebar metaphor, is a novel viewing method used to translate, rotate, and scale the point-cloud. Our new rendering technique uses the geometry shader to draw sparse point clouds quickly. The selection volumes at the controllers are our new technique to efficiently select points in point clouds. The resulting selection is visualized in real time. The results of the user study show that: - grabbing with a controller button is intuitive but throwing is not. Releasing a button is a bad metaphor for releasing a grabbed virtual object in order to throw it. - any feedback is better than none. Adding haptic, optical, or both feedback types to the grabbing improves the user performance and presence. However, only sub-scores like accuracy and predictability are significantly improved. Usability and task load are mostly unaffected by feedback. - the point-cloud editing is significantly better in VR with the bi-manual pinch gesture and selection volumes than on the desktop with the orbiting camera and lasso selections. ", month = jul, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "virtual reality, room-scale VR, throwing, grabbing, physics, basketball, haptic feedback, optical feedback, controllers, point cloud, point-cloud editing, presence, performance, usability, task load", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/ERLER-2017-HVR/", } @talk{Purgathofer-2017-VC-Interface, title = "Visual Computing als Interface zur Entscheidungsunterst\"{u}tzung", author = "Werner Purgathofer", year = "2017", month = jul, event = "RailTec 4.0 Workshop", location = "Wien", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/Purgathofer-2017-VC-Interface/", } @article{CORNEL-2017-FRS, title = "Forced Random Sampling: fast generation of importance-guided blue-noise samples", author = "Daniel Cornel and Hiroyuki Sakai and Christian Luksch and Michael Wimmer", year = "2017", abstract = "In computer graphics, stochastic sampling is frequently used to efficiently approximate complex functions and integrals. The error of approximation can be reduced by distributing samples according to an importance function, but cannot be eliminated completely. To avoid visible artifacts, sample distributions are sought to be random, but spatially uniform, which is called blue-noise sampling. The generation of unbiased, importance-guided blue-noise samples is expensive and not feasible for real-time applications. Sampling algorithms for these applications focus on runtime performance at the cost of having weak blue-noise properties. Blue-noise distributions have also been proposed for digital halftoning in the form of precomputed dither matrices. Ordered dithering with such matrices allows to distribute dots with blue-noise properties according to a grayscale image. By the nature of ordered dithering, this process can be parallelized easily. We introduce a novel sampling method called forced random sampling that is based on forced random dithering, a variant of ordered dithering with blue noise. By shifting the main computational effort into the generation of a precomputed dither matrix, our sampling method runs efficiently on GPUs and allows real-time importance sampling with blue noise for a finite number of samples. We demonstrate the quality of our method in two different rendering applications.", month = jun, journal = "The Visual Computer", volume = "33", number = "6", issn = "1432-2315", pages = "833--843", keywords = "blue-noise sampling, importance sampling", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/CORNEL-2017-FRS/", } @inproceedings{Ganuza-2017-IVCSGM, title = "Interactive Visual Categorization of Spinel-Group Minerals", author = " Mar\'{i}a Luj\'{a}n Ganuza and Gabriela Ferracutti and Maria Florencia Gargiulo and Silvia Castro and Ernesto Bjerg and Eduard Gr\"{o}ller and Kresimir Matkovic", year = "2017", abstract = "Spinel-group minerals are excellent indicators of geological environments and are of invaluable help in the search for mineral deposits of economic interest. The geologists analyze them by means of Barnes and Roeder’s contours. In this paper, we present a collection of novel, interactive methods, which assist geologists in the categorization of spinel-group minerals. We fully integrate Barnes and Roeder’s contours using a polygonal representation. This makes it possible to efficiently superimpose user-provided point data over the contours, and to automatically rank the contours based on the number of enclosed points. We also allow the expert to create contours for the user-provided point data. Once user contours are created, they can be compared with Barnes and Roeder’s contours. During the analysis, the user can drill-down by means of brushing. As we deal with specific data, we apply two novel brushing techniques, i.e., the percentile brush and the contour brush. The novel brushing mechanisms along with the interactive comparison speed-up the analysis significantly. We evaluate the newly introduced approach and the resulting novel workflow using real-word data from different locations in Argentina. According to the domain experts, the classification of spinel minerals needs several minutes now, while it took a few days with the current state of the art approach in the domain.", month = may, event = "33rd Spring Conference on Computer Graphics (SCCG 2017)", booktitle = "Proceedings of the 33rd Spring Conference on Computer Graphics (SCCG 2017)", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/Ganuza-2017-IVCSGM/", } @misc{Ganuza, title = "Visualizaci\'{o}n y Realidad Aumentada en el Campo de las Ciencias Geol\'{o}gicas", author = " Mar\'{i}a Luj\'{a}n Ganuza and J.M. Trippel Nagel and N.F. Gazc\'{o}n and Silvia Castro and Ernesto Bjerg and Maria Florencia Gargiulo and Gabriela Ferracutti and Kresimir Matkovic and Eduard Gr\"{o}ller", year = "2017", abstract = "En el campo de las Ciencias Geol\'{o}gicas, un desaf\'{i}o importante consiste en encontrar una representaci\'{o}n adecuada de una gran cantidad de datos de distintos tipos, que abarcan an\'{a}lisis de muestras minerales, datos topogr\'{a}ficos, proyecciones cartogr\'{a}ficas, datos geof\'{i}sicos, entre otros. La exploraci\'{o}n y an\'{a}lisis de estos datos requiere un soporte visual adecuado. Por otra parte, es importante la asistencia de dispositivos m\'{o}viles al momento de adquirir estos datos en el trabajo de campo. En esta l\'{i}nea de investigaci\'{o}n se est\'{a} trabajando en el diseño y la generaci\'{o}n de visualizaciones y de sistemas que las soporten con el objetivo de asistir al ge\'{o}logo en varias de sus tareas habituales. Por un lado, una sub-l\'{i}nea se refiere a la visualizaci\'{o}n de datos geol\'{o}gicos que provean un soporte adecuado para la exploraci\'{o}n eficiente de distintos conjuntos de datos de micro-qu\'{i}mica. Por otro, se trabaja en incorporar visualizaciones que asistan al ge\'{o}logo en la obtenci\'{o}n de datos geol\'{o}gicos en el trabajo de campo; esto se lleva a cabo mediante el uso de tecnolog\'{i}a de Realidad Aumentada y el uso de dispositivos m\'{o}viles.", month = apr, URL = "https://www.cg.tuwien.ac.at/research/publications/2017/Ganuza/", } @mastersthesis{Walch-2017-DA, title = "Lens Flare Prediction based on Measurements with Real-Time Visualization", author = "Andreas Walch", year = "2017", abstract = "Lens flare is a visual phenomenon caused by interreflection of light within a lens system. This effect is often undesired, but it gives rendered images a realistic appearance. In the area of computer graphics, several simulation based approaches have been presented to render lens flare for a given spherical lens system. An accurate model of the lens system and all its components is crucial for a physically reliable result. Since the effect differs from camera to camera, these methods are not flexible, and the internal parameters – especially the anti-reflection coatings – can only be approximated. In this thesis we present a novel workflow for generating physically plausible renderings of lens flare phenomena by analyzing the lens flares captured on a camera. Furthermore, our method allows to predict the occurrence of lens flares for a given light setup. This is an often requested feature in light planning applications in order to efficiently avoid lens flare prone light positioning. A model with a tight parameter set and a GPU-based rendering method allows our method to be used in real-time applications.", month = mar, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/Walch-2017-DA/", } @inproceedings{SCHWAERZLER-2017-SBGM, title = "Sketch-based Guided Modeling of 3D Buildings from Oriented Photos", author = "Michael Schw\"{a}rzler and Lisa-Maria Kellner and Stefan Maierhofer and Michael Wimmer", year = "2017", abstract = "Capturing urban scenes using photogrammetric methods has become an interesting alternative to laser scanning in the past years. For the reconstruction of CAD-ready 3D models, two main types of interactive approaches have become prevalent: One uses the generated 3D point clouds to reconstruct polygonal surfaces, while the other focuses on 2D interaction in the photos to define edges and faces. We propose a novel interactive system that combines and enhances these approaches in order to optimize current reconstruction and modeling workflows. Our main interaction target are the photos, allowing simple 2D interactions and edge-based snapping. We use the underlying segmented point cloud to define the 3D context in which the sketched polygons are projected whenever possible. An intuitive visual guiding interface gives the user feedback on the accuracy to expect with the current state of modeling to keep the necessary interactions at a minimum level.", month = feb, isbn = "978-1-4503-4886-7", publisher = "ACM", location = "San Francisco, CA", event = "I3D 2017", booktitle = "Proceedings of the 21st ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games", pages = "9:1--9:8", keywords = "3D modeling, guidance, photogrammetry", URL = "https://www.cg.tuwien.ac.at/research/publications/2017/SCHWAERZLER-2017-SBGM/", } @talk{purgathofer_2016I1, title = "Visual Computing — a best practice from Vienna", author = "Werner Purgathofer", year = "2016", month = dec, event = "National Research University – Higher School of Economics (HSE)", location = "Moskau", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/purgathofer_2016I1/", } @inproceedings{Reichinger-2016-spaghetti, title = "Spaghetti, Sink and Sarcophagus: Design Explorations of Tactile Artworks for Visually Impaired People", author = "Andreas Reichinger and Werner Purgathofer", year = "2016", month = oct, event = "9th Nordic Conference on CHI 2016", booktitle = "Proceedings of the 9th Nordic Conference on CHI 2016", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/Reichinger-2016-spaghetti/", } @article{Reichinger_2016, title = "Gesture-Based Interactive Audio Guide on Tactile Reliefs", author = "Andreas Reichinger and Stefan Maierhofer and Anton Fuhrmann and Werner Purgathofer", year = "2016", abstract = "For blind and visually impaired people, tactile reliefs offer many benefits over the more classic raised line drawings or tactile diagrams, as depth, 3D shape and surface textures are directly perceivable. However, without proper guidance some reliefs are still difficult to explore autonomously. In this work, we present a gesture-controlled interactive audio guide (IAG) based on recent low-cost depth cameras that operates directly on relief surfaces. The interactively explorable, location-dependent verbal descriptions promise rapid tactile accessibility to 2.5D spatial information in a home or education setting, to on-line resources, or as a kiosk installation at public places. We present a working prototype, discuss design decisions and present the results of two evaluation sessions with a total of 20 visually impaired test users.", month = oct, journal = "Proceedings of the 18th International ACM SIGACCESS Conference on Computers & Accessibility", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/Reichinger_2016/", } @mastersthesis{Spechtenhauser_Florian_2016, title = "Visual Analytics for Rule-Based Quality Management of Multivariate Data", author = "Florian Spechtenhauser", year = "2016", abstract = "Ensuring an appropriate data quality is a critical topic when analyzing the ever increasing amounts of data collected and generated in today’s world. Depending on the given task, even sophisticated analysis methods may cause misleading results due to an insufficient quality of the data set at hand. In this case, automated plausibility checks based on defined rules are frequently used to detect data problems such as missing data or anomalies. However, defining such rules and using their results for an efficient data quality assessment is a challenging topic. Visualization is powerful to reveal unexpected problems in the data, and can additionally be used to validate results of applied automated plausibility checks. Visual Analytics closes the gap between automated data analysis and visualization by providing means to guide the definition and optimization of plausibility checks in order to use them for a continuous detection and validation of problems detected in the data. This diploma thesis provides a design study of a Visual Analytics approach, called Data Quality Overview, which provides a detailed, yet scalable summary of the results of defined plausibility checks, and includes means for validation and investigation of these results at various levels of detail. The approach is based on a detailed task analysis of data quality assessment, and is validated using a case study based on sensor data from the energy sector in addition to feedback collected from domain experts.", month = aug, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/Spechtenhauser_Florian_2016/", } @article{ortner-2016-tunnel, title = "Visual analytics and rendering for tunnel crack analysis", author = "Thomas Ortner and Johannes Sorger and Harald Piringer and Gerd Hesina and Eduard Gr\"{o}ller", year = "2016", abstract = "The visual analysis of surface cracks plays an essential role in tunnel maintenance when assessing the condition of a tunnel. To identify patterns of cracks, which endanger the structural integrity of its concrete surface, analysts need an integrated solution for visual analysis of geometric and multivariate data to decide if issuing a repair project is necessary. The primary contribution of this work is a design study, supporting tunnel crack analysis by tightly integrating geometric and attribute views to allow users a holistic visual analysis of geometric representations and multivariate attributes. Our secondary contribution is Visual Analytics and Rendering, a methodological approach which addresses challenges and recurring design questions in integrated systems. We evaluated the tunnel crack analysis solution in informal feedback sessions with experts from tunnel maintenance and surveying. We substantiated the derived methodology by providing guidelines and linking it to examples from the literature.", month = may, journal = "The Visual Computer", volume = "32", number = "6", pages = "859--869", keywords = "Integration of spatial and non-spatial data, Methodology, Visual analytics", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/ortner-2016-tunnel/", } @article{ortner-2016-visaware, title = "Vis-a-ware: Integrating spatial and non-spatial visualization for visibility-aware urban planning", author = "Thomas Ortner and Johannes Sorger and Harald Steinlechner and Gerd Hesina and Harald Piringer and Eduard Gr\"{o}ller", year = "2016", abstract = "3D visibility analysis plays a key role in urban planning for assessing the visual impact of proposed buildings on the cityscape. A call for proposals typically yields around 30 candidate buildings that need to be evaluated with respect to selected viewpoints. Current visibility analysis methods are very time-consuming and limited to a small number of viewpoints. Further, analysts neither have measures to evaluate candidates quantitatively, nor to compare them efficiently. The primary contribution of this work is the design study of Vis-A-Ware, a visualization system to qualitatively and quantitatively evaluate, rank, and compare visibility data of candidate buildings with respect to a large number of viewpoints. Vis-A-Ware features a 3D spatial view of an urban scene and non-spatial views of data derived from visibility evaluations, which are tightly integrated by linked interaction. To enable a quantitative evaluation we developed four metrics in accordance with experts from urban planning. We illustrate the applicability of Vis-A-Ware on the basis of a use case scenario and present results from informal feedback sessions with domain experts from urban planning and development. This feedback suggests that Vis-A-Ware is a valuable tool for visibility analysis allowing analysts to answer complex questions more efficiently and objectively.", month = jan, journal = "Visualization and Computer Graphics, IEEE Transactions on", issn = "1077-2626 ", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/ortner-2016-visaware/", } @article{sorger-2015-litevis, title = "LiteVis: Integrated Visualization for Simulation-Based Decision Support in Lighting Design", author = "Johannes Sorger and Thomas Ortner and Christian Luksch and Michael Schw\"{a}rzler and Eduard Gr\"{o}ller and Harald Piringer", year = "2016", abstract = "State-of-the-art lighting design is based on physically accurate lighting simulations of scenes such as offices. The simulation results support lighting designers in the creation of lighting configurations, which must meet contradicting customer objectives regarding quality and price while conforming to industry standards. However, current tools for lighting design impede rapid feedback cycles. On the one side, they decouple analysis and simulation specification. On the other side, they lack capabilities for a detailed comparison of multiple configurations. The primary contribution of this paper is a design study of LiteVis, a system for efficient decision support in lighting design. LiteVis tightly integrates global illumination-based lighting simulation, a spatial representation of the scene, and non-spatial visualizations of parameters and result indicators. This enables an efficient iterative cycle of simulation parametrization and analysis. Specifically, a novel visualization supports decision making by ranking simulated lighting configurations with regard to a weight-based prioritization of objectives that considers both spatial and non-spatial characteristics. In the spatial domain, novel concepts support a detailed comparison of illumination scenarios. We demonstrate LiteVis using a real-world use case and report qualitative feedback of lighting designers. This feedback indicates that LiteVis successfully supports lighting designers to achieve key tasks more efficiently and with greater certainty.", month = jan, journal = "Visualization and Computer Graphics, IEEE Transactions on", volume = "22", number = "1", issn = "1077-2626 ", pages = "290--299", keywords = "Integrating Spatial and Non-Spatial Data", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/sorger-2015-litevis/", } @inproceedings{Reichinger_Fuhrmann_2016, title = "A Concept for Re-Useable Interactive Tactile Reliefs", author = "Andreas Reichinger and Anton Fuhrmann and Stefan Maierhofer and Werner Purgathofer", year = "2016", abstract = "We introduce a concept for a relief-printer, a novel production method for tactile reliefs, that allows to reproduce bas-reliefs of several centimeters height difference. In contrast to available methods, this printer will have a much smaller preparation time, and does not consume material nor produce waste, since it is based on a re-usable medium, suitable for temporary printouts. Second, we sketch a concept for the autonomous, interactive exploration of tactile reliefs, in the form of a gesture-controlled audio guide, based on recent depth cameras. Especially the combination of both approaches promises rapid tactile accessibility to 2.5D spatial information in a home or education setting, to on-line resources, or as a kiosk installation in museums.", booktitle = "A Concept for Re-Useable Interactive Tactile Reliefs", journal = "ICCHP 2016, Part II", URL = "https://www.cg.tuwien.ac.at/research/publications/2016/Reichinger_Fuhrmann_2016/", } @mastersthesis{MEINDL-2015-OSR, title = "Omnidirectional Stereo Rendering of Virtual Environments", author = "Lukas Meindl", year = "2015", abstract = "In this thesis we discuss the use of omnidirectional stereo (omnistereo) rendering of virtual environments. We present an artefact-free technique to render omnistereo images for the CAVE in real time using the modern rendering pipeline and GPU-based tessellation. Depth perception in stereoscopic images is enabled through the horizontal disparities seen by the left and right eye. Conventional stereoscopic rendering, using off-axis or toe-in projections, provides correct depth cues in the entire field of view (FOV) for a single view-direction. Omnistereo panorama images, created from captures of the real world, provide stereo depth cues in all view direction. This concept has been adopted for rendering, as several techniques generating omnistereo images based on virtual environments have been presented. This is especially relevant in the context of surround-screen displays, as stereo depth can be provided for all view directions in a 360° panorama simultaneously for upright positioned viewers. Omnistereo rendering also lifts the need for view-direction tracking, since the projection is independent of the view direction, unlike stereoscopic projections. However, omnistereo images only provide correct depth cues in the center of the FOV. Stereo disparity distortion errors occur in the periphery of the view and worsen with distance from the center of the view. Nevertheless, due to a number of properties of the human visual system, these errors are not necessarily noticeable. We improved the existing object-warp based omnistereo rendering technique for CAVE display systems by preceding it with screen-space adaptive tessellation methods. Our improved technique creates images without perceivable artefacts and runs on the GPU at real-time frame rates. The artefacts produced by the original technique without tessellation are described by us. Tessellation is used to remedy edge curvature and texture interpolation artefacts occurring at large polygons, due to the non-linearity of the omnistereo perspective. The original approach is based on off-axis projections. We showed that on-axis projections can be used as basis as well, leading to identical images. In addition, we created a technique to efficiently render omnistereo skyboxes for the CAVE using a pre-tessellated full-screen mesh. We implemented the techniques as part of an application for a three-walled CAVE in the VRVis research center and compared them.", month = nov, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "virtual reality, stereo rendering", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/MEINDL-2015-OSR/", } @inproceedings{sorger-2015-taxintec, title = "A Taxonomy of Integration Techniques for Spatial and Non-Spatial Visualizations", author = "Johannes Sorger and Thomas Ortner and Harald Piringer and Gerd Hesina and Eduard Gr\"{o}ller", year = "2015", abstract = "Research on visual data representations is traditionally classified into methods assuming an inherent mapping from data values to spatial coordinates (scientific visualization and real-time rendering) and methods for abstract data lacking explicit spatial references (information visualization). In practice, however, many applications need to analyze data comprising abstract and spatial information, thereby spanning both visualization domains. Traditional classification schemes do not support a formal description of these integrated systems. The contribution of this paper is a taxonomy that describes a holistic design space for integrating components of spatial and abstract visualizations. We structure a visualization into three components: Data, Visual, and Navigation. These components can be linked to build integrated visualizations. Our taxonomy provides an alternative view on the field of visualization in a time where the border between scientific and information visualization becomes blurred.", month = oct, series = "Springer Lecture Notes in Computer Science (LNCS) series", publisher = "The Eurographics Association", location = "Aachen, Germany", issn = "0302-9743", editor = "David Bommes and Tobias Ritschel and Thomas Schultz", booktitle = "20th International Symposium on Vision, Modeling and Visualization (VMV 2015)", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/sorger-2015-taxintec/", } @mastersthesis{May_Michael_2015_DIS, title = "Design and Implementation of a Shader Infrastructure and Abstraction Layer", author = "Michael May", year = "2015", abstract = "Programming the GPU is more important than ever, but the organization and development of shader code for the GPU is a difficult task. Can this process be embedded into the high level language C#, gain from the features of its toolchain and enrich shader development? For this purpose this thesis describes the design and implementation of a framework to abstract and embed shader development into C# with an internal domain-specific language (iDSL for short) as front-end and a plug-in system in the back-end to support expandable optimizations and different shader languages as targets. The implemented framework fits shader development into the C# toolchain, supporting autocompletion, and type error checking in the editor. The system offers good modularity and encourages developing shaders in reusable parts. This diploma thesis was developed in cooperation with VRVis Research Center in Vienna, Austria.", month = sep, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/May_Michael_2015_DIS/", } @inproceedings{Purg2015-China, title = "Industrial Use of Mixed Reality in VRVis Projects", author = "Werner Purgathofer and Clemens Arth and Dieter Schmalstieg", year = "2015", month = sep, organization = "VR Kebao (Tianjin) Science & Technology Co., Ltd", location = "Peking, China", booktitle = "Proceedings of VISIC", pages = "19--23", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/Purg2015-China/", } @mastersthesis{Wimmer_Maria_2015_SAS, title = "Semi-Automatic Spine Labeling on T1- and T2-weighted MRI Volume Data", author = "Maria Wimmer", year = "2015", abstract = "In medical diagnosis, the spine is often a frame of reference and so helps to localize diseases (e.g. tumors) in the human body. Automated spine labeling approaches are in demand, in order to replace time consuming, manual labeling by a radiologist. Different approaches have already been proposed in the literature, mainly for Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) data. While CT scans exhibit a generalized intensity scale, MR images come with a high variability within the data and hence the tissues. Several factors influence the appearance of vertebrae and intervertebral disks in MRI data: different scanners, changes of acquisition parameters, magnetic field inhomogeneities or age-related, structural changes of the spinal anatomy. These factors compound the development of semi- and fully automatic spine labeling systems. The main goal of this thesis is to overcome these variations and find a generalized representation for different kinds of MR data. Furthermore, it aims for a semi-automatic labeling approach on these preprocessed scans where the user has to provide an initial click. Entropyoptimized Texture Models are applied to normalize the data to a standardized, reduced intensity scale.With Probabilistic Boosting Trees, intervertebral disk feature points are detected, whereby the disk center is selected with a Shape Particle Filter. The results achieved with the proposed pipeline are promising in terms of data normalization, timing and labeling accuracy. With a mean overall processing time of 6.0 s for normalizing and labeling a dataset (0.8 s per disk), the algorithm achieves a precision of 92.4% (recall = 86.8%). Using a higher resolution of the data for disk detection (average timing of 1.6 s per disk resp. 12.4 s per dataset), reduces the number of missed disk candidates and hence increases the recall to 91.7% (with a precision of 91.9%).", month = jan, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/Wimmer_Maria_2015_SAS/", } @talk{Purgathofer-2015-WA, title = "\"{U}berblick Visual Computing: Teilbereiche und Anwendungsfelder", author = "Werner Purgathofer", year = "2015", event = "Business Treff "Visual Computing"", location = "Wien", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/Purgathofer-2015-WA/", } @talk{Purg2015-d, title = "Industrial Use of Mixed Reality in VRVis Projects", author = "Werner Purgathofer", year = "2015", event = "VISIC'2015 Int'l Symposium on Virtual Reality, Augmented Reality and Visual Computing Application Technology", location = "Beijing, China", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/Purg2015-d/", } @talk{Purg2015-c, title = "Computer Graphics in Real-World Applications", author = "Werner Purgathofer", year = "2015", event = "Visual Computing Workshop at the OCG-Jahrestagung", location = "Wien", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/Purg2015-c/", } @talk{Purg2015-b, title = "Visual Computing in \"{O}sterreich", author = "Werner Purgathofer", year = "2015", event = "Medienseminar Informatik der Plattform informatik_austria", location = "Wien", URL = "https://www.cg.tuwien.ac.at/research/publications/2015/Purg2015-b/", } @article{Matkovic-2014-ieee, title = "Visual Analytics for Complex Engineering Systems: Hybrid Visual Steering of Simulation Ensembles", author = "Kresimir Matkovic and Denis Gracanin and Rainer Splechtna and M. Jelovic and Benedikt Stehno and Helwig Hauser and Werner Purgathofer", year = "2014", abstract = "In this paper we propose a novel approach to hybrid visual steering of simulation ensembles. A simulation ensemble is a collection of simulation runs of the same simulation model using different sets of control parameters. Complex engineering systems have very large parameter spaces so a nai?ve sampling can result in prohibitively large simulation ensembles. Interactive steering of simulation ensembles provides the means to select relevant points in a multi-dimensional parameter space (design of experiment). Interactive steering efficiently reduces the number of simulation runs needed by coupling simulation and visualization and allowing a user to request new simulations on the fly. As system complexity grows, a pure interactive solution is not always sufficient. The new approach of hybrid steering combines interactive visual steering with automatic optimization. Hybrid steering allows a domain expert to interactively (in a visualization) select data points in an iterative manner, approximate the values in a continuous region of the simulation space (by regression) and automatically find the “best” points in this continuous region based on the specified constraints and objectives (by optimization). We argue that with the full spectrum of optimization options, the steering process can be improved substantially. We describe an integrated system consisting of a simulation, a visualization, and an optimization component. We also describe typical tasks and propose an interactive analysis workflow for complex engineering systems. We demonstrate our approach on a case study from automotive industry, the optimization of a hydraulic circuit in a high pressure common rail Diesel injection system.", month = dec, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "20", number = "12", issn = "1077-2626", pages = "1803--1812", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/Matkovic-2014-ieee/", } @incollection{Purgathofer-2014-PanEu, title = "Requirements on the Staff of an Application Oriented Research Organization", author = "Werner Purgathofer", year = "2014", abstract = "The VRVis Research Center in Vienna is the largest technology transfer institution in the area of Visual Computing in Austria. The requirements of the funding body FFG include the publication of scientific research results in first class peer reviewed media, and the active cooperation with co-funding companies. As a consequence the requirements on the staff of VRVis are manifold: they have to communicate with real users, use real data, know about software and hardware, understand the market, do professional documentation, initiate new projects and write funding proposals for these, be part of the scientific community and publish and review papers, manage several projects in parallel and obey strict deadlines for their projects and some more. Such staff is barely available and must be trained on the job.", month = dec, booktitle = "Current Issues of Science and Research in the Global World", chapter = "Proceedings of the International Conference on Current Issues of Science and Research in the Global World, Vienna, Austria; 27–28 May 2014", editor = "Vlasta Kunova, Martin Dolinsky", isbn = "9781138027398", note = "December 15, 2014 by CRC Press", publisher = "CRC Balkema Press, Netherlands", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/Purgathofer-2014-PanEu/", } @mastersthesis{CORNEL-2014-AFRS, title = "Analysis of Forced Random Sampling", author = "Daniel Cornel", year = "2014", abstract = "Stochastic sampling is an indispensable tool in computer graphics which allows approximating complex functions and integrals in finite time. Applications which rely on stochastic sampling include ray tracing, remeshing, stippling and texture synthesis. In order to cover the sample domain evenly and without regular patterns, the sample distribution has to guarantee spatial uniformity without regularity and is said to have blue-noise properties. Additionally, the samples need to be distributed according to an importance function such that the sample distribution satisfies a given sampling probability density function globally while being well distributed locally. The generation of optimal blue-noise sample distributions is expensive, which is why a lot of effort has been devoted to finding fast approximate blue-noise sampling algorithms. Most of these algorithms, however, are either not applicable in real time or have weak blue-noise properties. Forced Random Sampling is a novel algorithm for real-time importance sampling. Samples are generated by thresholding a precomputed dither matrix with the importance function. By the design of the matrix, the sample points show desirable local distribution properties and are adapted to the given importance. In this thesis, an efficient and parallelizable implementation of this algorithm is proposed and analyzed regarding its sample distribution quality and runtime performance. The results are compared to both the qualitative optimum of blue-noise sampling and the state of the art of real-time importance sampling, which is Hierarchical SampleWarping. With this comparison, it is investigated whether Forced Random Sampling is competitive with current sampling algorithms. The analysis of sample distributions includes several discrepancy measures and the sample density to evaluate their spatial properties as well as Fourier and differential domain analyses to evaluate their spectral properties. With these established methods, it is shown that Forced Random Sampling generates samples with approximate blue-noise properties in real time. Compared to the state of the art, the proposed algorithm is able to generate samples of higher quality with less computational effort and is therefore a valid alternative to current importance sampling algorithms. ", month = oct, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "global illumination, Poisson disk sampling", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/CORNEL-2014-AFRS/", } @article{LUKSCH-2014-RTR, title = "Real-Time Rendering of Glossy Materials with Regular Sampling", author = "Christian Luksch and Robert F. Tobler and Thomas M\"{u}hlbacher and Michael Schw\"{a}rzler and Michael Wimmer", year = "2014", abstract = "Rendering view-dependent, glossy surfaces to increase the realism in real-time applications is a computationally complex task, that can only be performed by applying some approximations—especially when immediate changes in the scene in terms of material settings and object placement are a necessity. The use of environment maps is a common approach to this problem, but implicates performance problems due to costly pre-filtering steps or expensive sampling. We, therefore, introduce a regular sampling scheme for environment maps that relies on an efficient MIP-map-based filtering step, and minimizes the number of necessary samples for creating a convincing real-time rendering of glossy BRDF materials.", month = jun, journal = "The Visual Computer", volume = "30", number = "6-8", issn = "0178-2789", pages = "717--727", keywords = "real-time rendering , BRDFs", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/LUKSCH-2014-RTR/", } @techreport{Purgathofer-2014-LSM, title = "A Live Services Marketplace: Telepresence through Remote Humans", author = "Werner Purgathofer and Hans J\"{u}rgen Pfisterer", year = "2014", abstract = "The basic idea is to use state-of-the-art telecommunication technology to implement the virtual presence of a person at a remote location. The concept is described with the use of modern mobile phones (smartphones), but several other devices with similar or extended capabilities could be used instead, including pads and notebooks, action cams and augmented reality glasses (e.g. Google eyeglasses). The person, who wants to be tele-present somewhere (let’s call this person the “pilot”), uses the smartphone to communicate with a person at the remote site (let’s call this person the “flyer”). The contact includes an acoustic connection, i.e. they can talk to each other, and a video connection, i.e. at least the pilot sees what the flyer is doing. The Live Services Marketplace describes a business how to connect pilots with flyers. Flyers can register their willingness to act as telepresence avatars for selected tasks from a list of allowable tasks, maintained to prevent illegal tasks. Pilots can book these flyers through a central administration system, which searches for appropriate flyers, anonymises the contact and organizes the financial arrangement. The audio and video connection is live only (just as a phone call). The paper describes the basic concept and many use cases for this business.", month = may, number = "TR-186-2-14-1", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", institution = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", note = "human contact: technical-report@cg.tuwien.ac.at", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/Purgathofer-2014-LSM/", } @talk{Purgathofer-2014-Rio, title = "Computer Graphics in Vienna and at the VRVis Research Center", author = "Werner Purgathofer", year = "2014", event = "Computer Graphics Lab at Universidade Federal do Rio de Janeiro", location = "Rio de Janeiro, Brazil", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/Purgathofer-2014-Rio/", } @talk{Purgathofer-2014-ETH, title = "Aspects of Scientific Research in Cooperation with Companies", author = "Werner Purgathofer", year = "2014", event = "20 Year Anniversary of CGL at ETH", location = "Z\"{u}rich, Switzerland", URL = "https://www.cg.tuwien.ac.at/research/publications/2014/Purgathofer-2014-ETH/", } @inproceedings{sorger-2013-neuromap, title = "neuroMAP - Interactive Graph-Visualization of the Fruit Fly's Neural Circuit", author = "Johannes Sorger and Katja B\"{u}hler and Florian Schulze and Tianxiao Liu and Barry Dickson", year = "2013", abstract = "Neuroscientists study the function of neural circuits in the brain of the common fruit fly Drosophila melanogaster to discover how complex behavior is generated. To establish models of neural information processing, knowledge about potential connections between individual neurons is required. Connections can occur when the arborizations of two neurons overlap. Judging connectivity by analyzing overlaps using traditional volumetric visualization is difficult since the examined objects occlude each other. A more abstract form of representation is therefore desirable. In collaboration with a group of neuroscientists, we designed and implemented neuroMap, an interactive two-dimensional graph that renders the brain and its interconnections in the form of a circuit-style wiring diagram. neuroMap provides a clearly structured overview of all possible connections between neurons and offers means for interactive exploration of the underlying neuronal database. In this paper, we discuss the design decisions that formed neuroMap and evaluate its application in discussions with the scientists.", month = oct, publisher = "IEEE", location = "Atlanta", booktitle = "Biological Data Visualization (BioVis), 2013 IEEE Symposium on ", pages = "73--80", URL = "https://www.cg.tuwien.ac.at/research/publications/2013/sorger-2013-neuromap/", } @talk{Purgathofer-2013-cvws, title = "Accurate Fast Simulation of Light", author = "Werner Purgathofer", year = "2013", abstract = "Light distribution in a scene is a very complex issue if it shall be close to realism. For a lamp producing and light planning company such as Zumtobel it is of great value to be able to design installations interactively, providing immediate feedback to the costumers about the final result. Many aspects such as reflections and indirect lighting make this task difficult. This talk will give some ideas how a project at the research center VRVis approaches this topic, and which algorithms are useful for this. Where can we simplify without visible loss? How can we use the GPU to speed up the calculations? Why are virtual lights an efficient concept? Some example images provide evidence. ", event = "The 18th Computer Vision Winter Workshop", location = "Hernstein, Austria", URL = "https://www.cg.tuwien.ac.at/research/publications/2013/Purgathofer-2013-cvws/", } @inproceedings{Eibner-12, title = " GPU-based Multi-Resolution Image Analysis for Synthesis of Tileable Textures", author = "Gottfried Eibner and Anton Fuhrmann and Werner Purgathofer", year = "2012", abstract = "We propose a GPU-based algorithm for texture analysis and synthesis of nearly-regular patterns, in our case scanned textiles or similar manufactured surfaces. The method takes advantage of the highly parallel execution on the GPU to generate correlation maps from captured template images. In an analysis step a lattice encoding the periodicity of the texture is computed. This lattice is used to synthesize the smallest texture tile describing the underlying pattern. Compared to other approaches, our method analyzes and synthesizes a valid lattice model without any user interaction. It is robust against small distortions and fast compared to other, more general approaches. ", month = jul, isbn = "978-3-642-33190-9", series = "Lecture Notes in Computer Science (LNCS) series", publisher = "Springer-Verlag", organization = "Symposium proceedings", location = "Creta, Greece", issn = "0302-9743", booktitle = "Proceedings Intern. Symposium on Visual Computing (ISVC 2012)", pages = "479--488", URL = "https://www.cg.tuwien.ac.at/research/publications/2012/Eibner-12/", } @inproceedings{reisner-2012-iwssip, title = "Segmenting Multiple Range Images with Primitive Shapes", author = "Irene Reisner-Kollmann and Stefan Maierhofer", year = "2012", abstract = "We introduce a novel method for automatically segmenting multiple registered range images by detecting and optimizing geometric primitives. The resulting shapes provide high level information about scanned objects and are a valuable input for surface reconstruction, hole filling, or shape analysis. We begin by generating a global graph of sample points covering all input frames. The graph structure allows to compute a globally consistent segmentation with a memory and time-efficient solution, even for large sets of input images. We iteratively detect shapes with a Ransac-approach, optimize the assignments of graph nodes to shapes, and optimize the shape parameters. Finally, pixel-accurate segmentations can be extracted for each source image individually. By using range images instead of unstructured point clouds as input, we can exploit additional information such as connectivity or varying precision of depth measurements.", month = apr, isbn = "978-3-200-02588-2", location = "Vienna", booktitle = "Proceedings of 19th International Conference on Systems, Signals and Image Processing (IWSSIP 2012)", keywords = "surface fitting, range data, segmentation, shape detection", URL = "https://www.cg.tuwien.ac.at/research/publications/2012/reisner-2012-iwssip/", } @inproceedings{reisner-2011-comdm, title = "Consolidation of Multiple Depth Maps", author = "Irene Reisner-Kollmann and Stefan Maierhofer", year = "2011", abstract = "Consolidation of point clouds, including denoising, outlier removal and normal estimation, is an important pre-processing step for surface reconstruction techniques. We present a consolidation framework specialized on point clouds created by multiple frames of a depth camera. An adaptive view-dependent locally optimal projection operator denoises multiple depth maps while keeping their struc ture in two-dimensional grids. Depth cameras produce a systematic variation of noise scales along the depth axis. Adapting to different noise scales allows to remove noise in the point cloud and preserve well-defined details at the same time. Our framework provides additional consolidation steps for depth maps like normal estimation and outlier removal. We show how knowledge about the distribution of noise in the input data can be effectively used for improving point clouds.", month = nov, location = "Barcelona", booktitle = "IEEE Workshop on Consumer Depth Cameras for Computer Vision (CDC4CV 2011)", URL = "https://www.cg.tuwien.ac.at/research/publications/2011/reisner-2011-comdm/", } @article{Berger_2011_UAE, title = "Uncertainty-Aware Exploration of Continuous Parameter Spaces Using Multivariate Prediction", author = "Wolfgang Berger and Harald Piringer and Peter Filzmoser and Eduard Gr\"{o}ller", year = "2011", abstract = "Systems projecting a continuous n-dimensional parameter space to a continuous m-dimensional target space play an important role in science and engineering. If evaluating the system is expensive, however, an analysis is often limited to a small number of sample points. The main contribution of this paper is an interactive approach to enable a continuous analysis of a sampled parameter space with respect to multiple target values. We employ methods from statistical learning to predict results in real-time at any user-defined point and its neighborhood. In particular, we describe techniques to guide the user to potentially interesting parameter regions, and we visualize the inherent uncertainty of predictions in 2D scatterplots and parallel coordinates. An evaluation describes a realworld scenario in the application context of car engine design and reports feedback of domain experts. The results indicate that our approach is suitable to accelerate a local sensitivity analysis of multiple target dimensions, and to determine a sufficient local sampling density for interesting parameter regions.", month = jun, journal = "Computer Graphics Forum", volume = "30", number = "3", note = "Best Paper Award", issn = "0167-7055", pages = "911--920", URL = "https://www.cg.tuwien.ac.at/research/publications/2011/Berger_2011_UAE/", } @inproceedings{reisner-2011-akgeo, title = "Reconstructing Buildings as Textured Low Poly Meshes from Point Clouds and Images", author = "Irene Reisner-Kollmann and Christian Luksch and Michael Schw\"{a}rzler", year = "2011", abstract = "Current urban building reconstruction techniques rely mainly on data gathered from either laser scans or image- based approaches, and do usually require a large amount of manual post-processing and modeling. Difficulties arise due to erroneous and noisy data, and due to the huge amount of information to process. We propose a system that helps to overcome these time-consuming steps by automatically generating low-poly 3D building models. This is achieved by taking both information from point clouds and image information into account, exploiting the particular strengths and avoiding the relative weaknesses of these data sources: While the segmented point cloud is used to identify the dominant planar surfaces in 3D space, the images are used to extract accurate edges, fill holes and generate textured polygonal meshes of urban buildings.", month = apr, location = "Llandudno, UK", editor = "Nick Avis and Sylvain Lefebvre", booktitle = "Eurographics 2011 - Short Papers", pages = "17--20", keywords = "Modeling packages, Computational Geometry and Object Modeli", URL = "https://www.cg.tuwien.ac.at/research/publications/2011/reisner-2011-akgeo/", } @misc{Gan-2011-ICU, title = "Interactive Visual Analysis of a large ICU database - a novel approach to data analysis", author = "H. Gan and Kresimir Matkovic and Andreas Ammer and Werner Purgathofer and W. Bennett and M. Terblanche", year = "2011", abstract = "ICUs generate vast amounts of valuable data. The size and complexity of the data make analysis technically demanding and time-consuming. We used interactive visual analysis (IVA) to analyse a large ICU database using the association between sodium and mortality as a case study. ", month = mar, journal = "Critical Care", volume = "15", number = "(suppl.1)", location = "Brussels, Belgium", issn = "1364-8535", event = "31st International Symposium on Intensive Care and Emergency Medicine", Conference date = "Poster presented at 31st International Symposium on Intensive Care and Emergency Medicine (2011-03-22--2011-03-25)", note = "135--", pages = "135 – ", URL = "https://www.cg.tuwien.ac.at/research/publications/2011/Gan-2011-ICU/", } @inproceedings{Reichinger-2011-Tac, title = "High-Quality Tactile Paintings", author = "Andreas Reichinger and Stefan Maierhofer and Werner Purgathofer", year = "2011", abstract = "The aim of this work is to bring the cultural heritage of two-dimensional art closer to being accessible by blind and visually impaired people. We present a computer-assisted workflow for the creation of tactile representations of paintings, suitable to be used as a learning tool in the context of guided tours in museums or galleries. Starting from high-resolution images of original paintings, our process allows an artist to quickly design the desired form, and generate data suitable for rapid prototyping machines to produce the physical touch tools. Laser-cut layered depth diagrams, convey not only the individual objects in the painting and their spatial layout, but also augment their depth relations. CNC-milled textured reliefs additionally render fine details like brush strokes and texture suitable for the sense of touch. Our methods mimic aspects of the visual sense, make sure that the haptic output is quite faithful to the original paintings and do not require special manual abilities, like sculpting skills.", organization = "Eurographics", location = "Llandudno, UK", editor = "A. Day and R. Mantiuk and E. Reinhard and R. Scopigno", booktitle = "Eurographics 2011 - Areas Papers", pages = "1--8", URL = "https://www.cg.tuwien.ac.at/research/publications/2011/Reichinger-2011-Tac/", } @inproceedings{Mantler-2011-GEAR, title = "GEARViewer: A State of the Art Real-Time Geospatial Visualization Framework", author = "Stephan Mantler and Gerd Hesina and Michael Greiner and Werner Purgathofer", year = "2011", abstract = "Geospatial visualization is playing an increasingly important part in the planning and public discussion of infrastructure projects. In addition to pre-rendered highly realistic imagery, interactive viewers have become an important tool for this task. Advances in rendering technology and performance have reduced the gap in visual quality between pre-rendered imagery and real-time applications, and the additional possibilities of a live visualization may become important tools in the decision making process. Historically, the step from GIS data or a highly detailed architectural model to a representation that is suitable for real-time display has been complex and required a very finely tuned workflow. On the other side, the general public is relatively spoiled by the extremely high quality of computer games and CGI films. Naturally, a tremendous amount of work and time is typically spent to fully optimize computer games for the available hardware. This is usually not possible for geospatial visualization tasks, but nonetheless current interactive viewing applications must strive to achieve similar quality and performance to be successful. In this paper, we present GEARViewer, a state of the art geospatial rendering framework developed at VRVis. Developed in close cooperation with major stakeholders in the Austrian road and railway infrastructure, it bridges the gap between GIS applications and real-time rendering, and achieves a high degree of realism and performance while supporting many of the tasks involved in geospatial visualizations.", isbn = "978-3-9503110-1-3", editor = "Manfred SCHRENK, Vasily V. POPOVICH, Peter ZEILE", booktitle = "Proceedings of CORP 2011", pages = "345--354", URL = "https://www.cg.tuwien.ac.at/research/publications/2011/Mantler-2011-GEAR/", } @inproceedings{musialski-2010-imv, title = "Interactive Multi-View Fa\c{c}ade Image Editing", author = "Przemyslaw Musialski and Christian Luksch and Michael Schw\"{a}rzler and Matthias Buchetics and Stefan Maierhofer and Werner Purgathofer", year = "2010", abstract = "We propose a system for generating high-quality approximated fa\c{c}ade ortho-textures based on a set of perspective source photographs taken by a consumer hand-held camera. Our approach is to sample a combined orthographic approximation over the fa\c{c}ade-plane from the input photos. In order to avoid kinks and seams which may occur on transitions between different source images, we introduce color adjustment and gradient domain stitching by solving a Poisson equation in real-time. In order to add maximum control on the one hand and easy interaction on the other, we provide several editing interactions allowing for user-guided post-processing.", month = nov, location = "Siegen, Germany", booktitle = "Vision, Modeling and Visualization Workshop 2010", keywords = "urban reconstruction, facade image processing", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/musialski-2010-imv/", } @inproceedings{Przemyslaw-2010-ADS, title = "A Device-aware Spatial 3D Visualization Platform for Mobile Urban Exploration ", author = "Matthias Baldauf and Przemyslaw Musialski", year = "2010", abstract = "Mobile devices displaying 2D map representations are already commonly used for the exploration of urban surroundings on the move. Even though mobile detailed 3D visualizations promise to be an attractive way to cope with the increasing amount of georeferenced information, their widespread use is hampered by the fragmentation of today’s mobile device landscape. In this paper, we tackle this real-world problem by introducing a device-aware 3D visualization service platform. Its core is composed of a rule engine selecting and tailoring a suitable visualization process for a requesting device. While we apply remote-renderings for resource-restrained mobile devices, real-time on-device renderings are applied for high-end devices. Following this device-aware approach, a variety of mobile devices with different technical capabilities can be provided with tailored environmental 3D representations for mobile urban exploration.", month = oct, isbn = "978-1-61208-000-0", organization = "The Fourth International Conference on Mobile Ubiquitous Computing, Systems, Services and Technologies (UBICOMM 2010)", location = "Florenz, Italien", booktitle = "Proceedings of the Fourth International Conference on Mobile Ubiquitous Computing, Systems, Services and Technologies (UBICOMM 2010)", pages = "47--52", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/Przemyslaw-2010-ADS/", } @phdthesis{musialski-2010-pfi, title = "Processing of Fa\c{c}ade Imagery", author = "Przemyslaw Musialski", year = "2010", abstract = "Modeling and reconstruction of urban environments is currently the subject of intensive research. There is a wide range of possible applications, including virtual environments like cyber-tourism, computer games, and the entertainment industries in general, as well as urban planning and architecture, security planning and training, traffic simulation, driving guidance and telecommunications, to name but a few. The research directions are spread across the disciplines of computer vision, computer graphics, image processing, photogrammetry and remote sensing, as well as architecture and the geosciences. Reconstruction is a complex problem and requires an entire pipeline of different tasks. In this thesis we focus on processing of images of fa\c{c}ades which is one specific subarea of urban reconstruction. The goal of our research is to provide novel algorithmic solutions for problems in fa\c{c}ade imagery processing. In particular, the contribution of this thesis is the following: First, we introduce a system for generation of approximate orthogonal fa\c{c}ade images. The method is a combination of automatic and interactive tools in order to provide a convenient way to generate high-quality results. The second problem addressed in this thesis is fa\c{c}ade image segmentation. In particular, usually by segmentation we mean the subdivision of the fa\c{c}ade into windows and other architectural elements. We address this topic with two different algorithms for detection of grids over the fa\c{c}ade image. Finally, we introduce one more fa\c{c}ade processing algorithm, this time with the goal to improve the quality of the fa\c{c}ade appearance. The algorithm propagates visual information across the image in order to remove potential obstacles and occluding objects. The output is intended as source for textures in urban reconstruction projects. The construction of large three-dimensional urban environments itself is beyond the scope of this thesis. However, we propose a suite of tools together with mathematical foundations that contribute to the state-of-the-art and provide helpful building blocks important for large scale urban reconstruction projects.", month = oct, address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", keywords = "facade processing, urban reconstruction, image processing", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/musialski-2010-pfi/", } @inproceedings{matkovic-2010-eventlineview, title = "Event Line View: Interactive Visual Analysis of Irregular Time-dependent Data", author = "Kresimir Matkovic and Andreas Ammer and Denis Gracanin and Werner Purgathofer and Alan Lez", year = "2010", abstract = "In this paper we present a novel approach to visualize ir- regularly occurring events. We introduce the event line view designed speci¯cally for such events data (a subset of time dependent data). The event line view is integrated in a coordinated multiple views (CMV) system and linked with other conventional views to support interactive visual analysis. The main idea is to analyze events relative to two cat- egorical attributes from a multidimensional multivariate dataset. Since we are interested in the categorical dimension we have also integrated and linked the tag cloud view in the CMV system. To the best of our knowledge this is the ¯rst integration of the tag cloud view in a CMV system. The tag cloud view can depict a ratio of the selected items versus the non-selected items. The proposed approach is illustrated using the VAST Challenge 2008 Geo-Spatial data set that contains data on interdiction or landing of ille- gal immigrants in the USA. It is a multivariate multidimensional dataset with irregular events that illustrates the potential and capabilities of the proposed approach and the developed CMV system.", month = jun, publisher = "Springer", location = "Banff, Canada", booktitle = "Smart Graphics 2010", keywords = "Interactive Visual Analysis, Coordinated Multiple Views, Tag Cloud, Events in Time", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/matkovic-2010-eventlineview/", } @inproceedings{musialski-2010-tof, title = "Tiling of Ortho-Rectified Fa\c{c}ade Images", author = "Przemyslaw Musialski and Meinrad Recheis and Stefan Maierhofer and Peter Wonka and Werner Purgathofer", year = "2010", abstract = "Typical building facades consist of regular structures such as windows arranged in a predominantly grid-like manner. We propose a method that handles precisely such facades and assumes that there must be horizontal and vertical repetitions of similar patterns. Using a Monte Carlo sampling approach, this method is able to segment repetitive patterns on orthogonal images along the axes even if the pattern is partially occluded. Additionally, it is very fast and can be used as a preprocessing step for finer segmentation stages.", month = may, isbn = "978-80-223-2644-5", publisher = "Comenius University, Bratislava", location = "Budmerice, Slovak Republic", editor = "Helwig Hauser , Reinhard Klein", booktitle = "Proceedings of 26th Spring Conference on Computer Graphics (SCCG 2010)", keywords = "image processing, facade segmentation, urban reconstruction", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/musialski-2010-tof/", } @inproceedings{reisner-2010-ind, title = "Interactive reconstruction of industrial sites using parametric models", author = "Irene Reisner-Kollmann and Anton Fuhrmann and Werner Purgathofer", year = "2010", abstract = "We present a new interactive modeling technique for reconstructing 3D objects from multiple images. We specifically address the problems that arise in industrial environments during camera orientation, image segmentation and modeling. An accurate camera orientation is ensured by using coded markers and surveyed points from a total station. Interactive segmentations of edges and regions in the images are used as input for fitting parametric models to the scene. We provide an intuitive interface which allows modeling artificial objects without having extensive knowledge about 3D modeling or photogrammetry.", month = may, isbn = "978-80-223-2644-5", publisher = "Comenius University, Bratislava", location = "Budmerice, Slovak Republic", editor = "Helwig Hauser , Reinhard Klein", booktitle = "Proceedings of 26th Spring Conference on Computer Graphics (SCCG 2010)", pages = "119--126", keywords = "multi-view reconstruction, model fitting", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/reisner-2010-ind/", } @inproceedings{brunnhuber-2010-behavior-handicapped, title = "Simulation and Visualization of the Behavior of Handicapped People in Virtually Reconstructed Public Buildings", author = "Martin Brunnhuber and H. Schrom-Feiertag and Gerd Hesina and D. Bauer and Werner Purgathofer", year = "2010", abstract = "The planning of public transport infrastructures today must respect the needs of a wide variety of travelers. In particular the design of guiding systems needs to take the reduced reception capabilities of the elderly and handicapped people into account. Therefore tools for the evaluation of guiding systems need to be developed. Such tools must be based on empirical knowledge on the perception capabilities of the various user groups as well as detailed microscopic pedestrian movement models in order to represent typical paths taken. We model the cognition of guiding systems to enable a realistic representation for the motion and orientation behavior of elderly and handicapped people having difficulties perceiving the guidance information and not being familiar with a building. To demonstrate the feasibility of the approach we discuss a technique to virtually reconstruct public buildings in 3D and visualize the simulated crowd with detailed models for each individual. The lines of sight of selected, handicapped persons, who are moving amongst other persons, are also shown in order to evaluate the visibility of the guiding information in the infrastructure and to hint at possible improvements.", booktitle = "CORP 2010", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/brunnhuber-2010-behavior-handicapped/", } @inproceedings{reisner-2010-1dh, title = "3D Camera Pose Estimation using Line Correspondences and 1D Homographies", author = "Irene Reisner-Kollmann and Andreas Reichinger and Werner Purgathofer", year = "2010", abstract = "This paper describes a new method for matching line segments between two images in order to compute the relative camera pose. This approach improves the camera pose for images lacking stable point features but where straight line segments are available. The line matching algorithm is divided into two stages: At first, scale-invariant feature points along the lines are matched incorporating a one-dimensional homography. Then, corresponding line segments are selected based on the quality of the estimated homography and epipolar constraints. Based on two line segment correspondences the relative orientation between two images can be calculated.", isbn = "978-3-642-17273-1", series = "Lecture Notes in Computer Science", publisher = "Springer", location = "Las Vegas, Nevada, USA", editor = "Bebis, G.; Boyle, R.; Parvin, B.; Koracin, D.; Chung, R.; Hammoud, R.; Hussain, M.; Tan, K.-H.; Crawfis, R.; Thalmann, D.; Kao, D.; Avila, L.", booktitle = "Advances in Visual Computing: 6th International Symposium on Visual Computing (ISVC 2010)", pages = "41--52", keywords = "pose estimation, line matching", URL = "https://www.cg.tuwien.ac.at/research/publications/2010/reisner-2010-1dh/", } @inproceedings{musialski-2009-sbfr, title = "Symmetry-Based Facade Repair", author = "Przemyslaw Musialski and Peter Wonka and Meinrad Recheis and Stefan Maierhofer and Werner Purgathofer", year = "2009", abstract = "In this paper we address the problem of removing unwanted image content in a single orthographic facade image. We exploit the regular structure present in building facades and introduce propagation process that is guided by the symmetry prevalent in the image. It removes larger unwanted image objects such as traffic lights, street signs, or cables as well as smaller noise, such as reflections in the windows. The output is intended as source for textures in urban reconstruction projects.", month = nov, isbn = "978-3980487481", location = "Braunschweig", editor = "Marcus Magnor, Bodo Rosenhahn, Holger Theisel ", booktitle = "Vision, Modeling, and Visualization Workshop 2009", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/musialski-2009-sbfr/", } @misc{Konyha_2009_survey, title = "Interactive Visual Analysis in Engineering: A Survey", author = "Zoltan Konyha and Kresimir Matkovic and Helwig Hauser", year = "2009", abstract = "Interactive visual analysis has become a very popular research field. There is a significant body of literature on making sense of massive data sets, on visualization and interaction techniques as well as on analysis concepts. However, surveying how those results can be applied to actual engineering problems, including both product and manufacturing design as well as evaluation of simulation and measurement data, has not been discussed sufficiently to date. In this paper we provide a selection of demonstration cases that document the potential benefits of using interactive visual analysis in a wide range of engineering domains, including the investigation of flow and particle dynamics, automotive engine design tasks and change management in the product design process. We attempt to identify some of the proven technological details such as the linking of space-time and attribute views through an application-wide coherent selection mechanism. This paper might be an interesting survey for readers with a relation to the engineering sector, both reflecting on available technological building blocks for interactive visual data analysis as well as exemplifying the potential benefits on behalf of the application side.", month = apr, publisher = "ACM", location = "Budmerice, Slowakei", issn = "ISSN 1335-5694", booktitle = "Posters at SCCG 2009", Conference date = "Poster presented at (2009-04-23--2009-04-25)", note = "31--38", pages = "31 – 38", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/Konyha_2009_survey/", } @misc{kim_2009_iPhone, title = "iPhone/iPod Touch as Input Devices for Navigation in Immersive Virtual Environments", author = "Ji-Sun Kim and Denis Gracanin and Kresimir Matkovic and Francis Quek", year = "2009", abstract = "iPhone and iPod Touch are multi-touch handheld devices that provide new possibilities for interaction techniques. We describe iPhone/iPod Touch implementation of a navigation interaction technique originally developed for a larger multi-touch device (i.e. Lemur). The interaction technique implemented on an iPhone/iPod Touch was used for navigation tasks in a CAVE virtual environment. We performed a pilot study to measure the control accuracy and to observe how human subjects respond to the interaction technique on the iPhone and iPod Touch devices. We used the preliminary results to improve the design of the interaction technique.", month = mar, publisher = "IEEE", location = "Lafayette, Louisiana, USA", isbn = "978-1-4244-3943-0", event = "Virtual Reality Conference, 2009", editor = "Anthony Steed, Dirk Reiners, Robert W. Lindeman", booktitle = "Proceedings of IEEE VR 2009", Conference date = "Poster presented at Virtual Reality Conference, 2009 (2009-03-14--2009-03-18)", note = "261--262", pages = "261 – 262", URL = "https://www.cg.tuwien.ac.at/research/publications/2009/kim_2009_iPhone/", } @article{Freiler-2008-Set, title = "Interactive Visual Analysis of Set-Typed Data", author = "Wolfgang Freiler and Kresimir Matkovic and Helwig Hauser", year = "2008", abstract = "While it is quite typical to deal with attributes of different data types in the visualization of heterogeneous, multivariate datasets, most existing techniques still focus on the most usual data types such as numerical attributes or strings. In this paper we present a new approach to the interactive visual exploration and analysis of data that contains attributes which are of set type. A set-typed attribute of a data item – like one cell in a table – has a list of n ¸ 0 elements as a value. We present the set’o’gram as a visualization approach to represent data of set type and to enable interactive visual analysis. We also demonstrate how this approach is capable to help in dealing with datasets that have truly many dimensions (more than a dozen or more), especially in the context of categorical data. To illustrate the effectiveness of our approach, we present the interactive visual analysis of a CRM dataset with data from a questionnaire on the education and shopping habits of about 90000 people.", month = nov, journal = "IEEE Transactions on Visualization and Computer Graphics", volume = "14", number = "6", keywords = "Interactive Visual Analysis, Multiple Coordinated Views, Focus & Context, Categorical Data, Multidimensional Multivariate Data", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Freiler-2008-Set/", } @article{Matkovic-2008-Steer, title = "Interactive Visual Steering – Rapid Visual Prototyping of a Common Rail Injection System", author = "Kresimir Matkovic and Denis Gracanin and M. Jelovic and Helwig Hauser", year = "2008", abstract = "Interactive steering with visualization has been a common goal of the visualization research community for twenty years, but it is rarely ever realized in practice. In this paper we describe a successful realization of a tightly coupled steering loop, integrating new simulation technology and interactive visual analysis in a prototyping environment for automotive industry system design. Due to increasing pressure on car manufacturers to meet new emission regulations, to improve efficiency, and to reduce noise, both simulation and visualization are pushed to their limits. Automotive system components, such as the powertrain system or the injection system, have an increasing number of parameters, and new design approaches are required. It is no longer possible to optimize such a system solely based on experience or forward optimization. By coupling interactive visualization with the simulation back-end (computational steering), it is now possible to quickly prototype a new system, starting from a non-optimized initial prototype and the corresponding simulation model. The prototyping continues through the refinement of the simulation model, of the simulation parameters and through trial-and-error attempts to an optimized solution. The ability to early see the first results from a multidimensional simulation space — thousands of simulations are run for a multidimensional variety of input parameters — and to quickly go back into the simulation and request more runs in particular parameter regions of interest significantly improves the prototyping process and provides a deeper understanding of the system behavior. The excellent results which we achieved for the common rail injection system strongly suggest that our approach has a great potential of being generalized to other, similar scenarios.", month = nov, journal = "IEEE Transactions on Visualization and Computer Graphics ", volume = "14", number = "6", keywords = "Interactive computational steering, interactive visual analysis, simulation, common rail injection system", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Matkovic-2008-Steer/", } @inproceedings{Kim-2008_FWIP, title = "Finger Walking in Place (FWIP): a Traveling Technique in Virtual Environments", author = "Ji-Sun Kim and Denis Gracanin and Kresimir Matkovic and Francis Quek", year = "2008", abstract = "In this paper we present a Finger Walking in Place (FWIP) interaction technique that allows a user to travel in a virtual world as her/his bare ¯ngers slide on a multi-touch sensitive surface. Traveling is basically realized by translating and rotating the user's viewpoint in the virtual world. The user can translate and rotate a viewpoint by mov- ing her/his ¯ngers in place. Currently, our FWIP technique can be used to navigate in a plane but it can be extended to navigate in the third axis, so that the user can move to any direction in a 3D virtual world. Since our FWIP technique only uses bare ¯ngers and a multi-touch de- vice, ¯nger motions are not precisely detected, especially compared with the use of data gloves or similar sensing devices. However, our experi- ments show that FWIP can be used as a novel traveling technique even without accurate motion detection. Our experiment tasks include ¯nding and reaching the target(s) with FWIP, and the participants successfully completed the tasks. The experiments illustrate our e®orts to make the FWIP technique robust as a scaled-down walking-in-place locomotion technique, so that it can be used as a reliable traveling technique.", month = aug, isbn = "978-3-540-85410-4", series = "LNCS", publisher = "Springer", location = "Rennes, France", issn = "0302-9743 (Print) 1611-3349 (Online)", booktitle = "Proceedings of SmartGraphics 2008, Springer LNCS 5166/2008", keywords = "Virtual environments, Finger-walking, Navigation, Traveling techniques, Multi-touch device", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Kim-2008_FWIP/", } @inproceedings{Matkovic-2008-ComVis, title = "ComVis: a Coordinated Multiple Views System for Prototyping New Visualization Technology", author = "Kresimir Matkovic and Wolfgang Freiler and Denis Gracanin and Helwig Hauser", year = "2008", abstract = "There is a large number of interactive visualization tools, however no universal tool exists that covers all relevant aspects for all possible application domains. We have developed a tool, ComVIs, which was intended to be used as a research prototype for new visualization techniques. We have identified some interesting aspects from developers and users point of view during tool development. In this paper we describe lessons learned during the process, and share our findings with visualization research community. Examples at the end prove the usefulness of the developed tool. One particular example, the concept of families of function graphs and application to analysis of fuel injection concludes the paper.", month = jul, location = "London, UK", booktitle = "Proceedings of the 12th International Conference Information Visualisation", keywords = "visualization tool, visual analysis, information visualization, system design", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Matkovic-2008-ComVis/", } @inproceedings{Trobec-2008-Heart, title = "Visual Analysis of Heart Reinervation after Transplantation", author = "Roman Trobec and Kresimir Matkovic and Karolj Skala and Silvia Samarin and Matjaz Depolli and Viktor Avbelj", year = "2008", abstract = "During heart transplantation complete denervation of allograft occurs. Partial reinnervation may develop after one year or later. It can be detected by different methods i.e., iodine- 123-meta-iodobenziylguanidine (MIBG) scintigraphy, positron emission tomography (PET), heart rate variability (HRV), etc. We propose an alternative noninvasive method based on visual diagnostics (VD) and supported by a custom developed tool (ComVis), which enables interactive visual analysis of large data sets by exploiting focus and context (simultaneous local and global view), multiple coordinated views and advanced interaction. Measurements of patients with transplanted heart are rare and valuable, therefore they should be analyzed in all details. Different statistical characteristics and time series from ECG and respiration measurements from fifteen patients and twelve healthy controls have been analyzed using the ComVis tool. MIBG scintigraphy imaging was included, as well. Heart to mediastinum ratio (HMR) was used as a measure of the ventricular reinervation. HRV was analyzed to evaluate sinus node reinnervation. HRV was synchronized on well defined expiration moment and analyzed in time-domain.We will describe some new diagnostic results or rules that were deduced from interactive visual analysis and may help in the future investigation of heart reinervation.", month = may, location = "Opatija, Croatia", booktitle = "Proceedings of the MIPRO 2008", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Trobec-2008-Heart/", } @misc{Singh-2008-Metric, title = "A Load Simulation and Metrics Framework for Distributed Virtual Reality", author = "H. Lally Singh and Denis Gracanin and Kresimir Matkovic", year = "2008", abstract = "We describe a simple load-measure-model method for analyzing the scalability of Distributed Virtual Environments (DVEs). We use a load simulator and three metrics to measure a DVE’s engine with varying numbers of simulated users. Our load simulator logs in as a remote client and plays according to how users played during the conducted user study. Two quality of virtuality metrics, fidelity and consistency, describe the user’s experience in the DVE. One engine performance metric provides the cycle time of the engine’s primary loop. Simulation results (up to 420 users) are discussed.", month = mar, publisher = "IEEE", note = "Lecturer: Denis Gracanin", location = "Reno, Nevada USA", isbn = "978-1-4244-1971-5", event = "Virtual Reality Conference, 2008. VR ", editor = "Reno, Nevada, USA", Conference date = "Poster presented at Virtual Reality Conference, 2008. VR (2008-03-08--2008-03-12)", note = "287--288", pages = "287 – 288", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Singh-2008-Metric/", } @talk{Matkovic-2008-med, title = " Interactive visual Analysis-Potential Aplications in Medicine", author = "Kresimir Matkovic", year = "2008", event = "1st International Congress of Hemodynamic Monitoring", location = "Zagreb Croatia", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Matkovic-2008-med/", } @talk{Matkovic-2008-Bergen, title = "Interactive Visual Steering – Our Experiences", author = "Kresimir Matkovic", year = "2008", abstract = "Interactive steering with visualization has been a central goal of the international visualization research community for twenty years. Still, we rarely ever see it applied to real-world problems. Here we describe our recent experiences with a realization of a tightly coupled steering loop, integrating simulation and interactive visual analysis in a prototyping environment for automotive industry system design. Very positive feedback from domain experts proves the usefulness of the approach.", event = "Visualization Seminar", location = "Bergen, Norway", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Matkovic-2008-Bergen/", } @misc{Ahmed-2008-EGVE, title = "An Approach to Interaction Interoperability for Distributed Virtual Environments", author = "Husein M. Ahmed and Denis Gracanin and Ayman Abdel-Hamid and Kresimir Matkovic", year = "2008", abstract = "We present a preliminary framework for interaction interoperability in distributed virtual environments. The goal is to allow each user to use a different input devices and interaction techniques and yet collaborate seamlessly. The framework adopts a service oriented architecture and use a knowledge base in the form of three ontologies. The ontologies use Web Ontology Language (OWL) to describe input devices, interaction techniques and interaction tasks. In addition, two directories contain application and user profiles. An inference engine searches for the best possible combination of input devices, interaction techniques and tasks. The resulting user’s mapping file is then accessed using the framework distributed web service. Two proof-of-concept framework implementations demonstrate how to develop a new application and how to support a legacy application.", location = "Eindhoven, Holland", event = "Virtual Environments 2008", booktitle = "Short papers and posters proceedings of the EGVE 2008", Conference date = "Poster presented at Virtual Environments 2008 (2008-05-29--2008-05-30)", note = "35--38", pages = "35 – 38", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Ahmed-2008-EGVE/", } @article{ilcik-2008-sgfa, title = "A Semi-Global Approach to Interactive Visual Analysis of Multivariate Flow Simulation Data", author = "Martin Il\v{c}\'{i}k", year = "2008", abstract = "We introduce a framework for interactive visualization of global flow features in large unsteady 3D flow fields. It is based on selective visualization using dense precomputed integral lines (streamlines, path lines) linked together with all other data attributes. This way we are able to provide an uniform and interactive environment for custom feature specification and visualization of non-local data aspects. These are related to the long term flow behavior, thus their description using only local properties is not possible. We demonstrate the benefits of working with semi-global features by a simple strategy for recognition of recirculation zones within 3D vector fields, judging on a self-proximity measure of integral lines.", issn = "1811-8992", journal = "Computer Graphics & Geometry", number = "3", volume = "10", pages = "18--35", keywords = "global features, integral lines, flow visualization, recirculation", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/ilcik-2008-sgfa/", } @inproceedings{Miklin-2009-Mig, title = "Migrant Boat Mini Challenge Award: Simple and Effective Integrated Display Geo-Temporal Analysis of Migrant Boats", author = "Ranko Miklin and Tomislav Lipic and Zoltan Konyha and Mario Beric and Wolfgang Freiler and Kresimir Matkovic and Denis Gracanin", year = "2008", abstract = "We provide a description of the tools and techniques used in our analysis of the VAST 2008 Challenge dealing with mass movement of persons departing Isla Del Sue˜no on boats for the United States during 2005–2007. We used visual analytics to explore migration patterns, characterize the choice and evolution of landing sites, characterize the geographical patterns of interdictions and determine the successful landing rate. Our ComVis tool, in connection with some helper applications and Google Earth, allowed us to explore geo-temporal characteristics of the data set and answer the challenge questions. The ComVis project file captures the visual analysis context and facilitates better collaboration among team members.", booktitle = "Proceedings of IEEE VAST 2008 Symposium", location = "Columbus, Ohio", keywords = "geo-temporal data, visual analytics", URL = "https://www.cg.tuwien.ac.at/research/publications/2008/Miklin-2009-Mig/", } @inproceedings{matkovic-2007-clv, title = "Color Lines View: An Approach to Visualization of Families of Function Graphs", author = "Kresimir Matkovic and Denis Gracanin and Zoltan Konyha and Helwig Hauser", year = "2007", abstract = "Data sets often include information that can be represented as a mapping that describes how a dependent variable depends on an independent variable. Such a mapping, usually represented as a function graph, can be parameterized to provide a family of function graphs. The challenge is how to efficiently aggregate individual function graph views to represent the whole family and allow visual analysis and search for patterns. We propose a novel view, called the color lines view, which provides a two dimensional, rectangular view where each line represents a single function graph. The points on the line correspond to values of the independent variable. The point colors represent the value of the dependent variable. The lines, placed next to each other in parallel, show a family of function graphs. The color lines view offers sorting and brushing features which support visual analysis procedures that are difficult to perform with previously existing views.", month = jul, location = "Z\"{u}rich, Schweiz", booktitle = "Proceedings of 11th International Conference Information Visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/matkovic-2007-clv/", } @inproceedings{Konyha_2007_SCV, title = "Interactive Visual Analysis of a Timing Chain Drive Using Segmented Curve View and other Coordinated Views", author = "Zoltan Konyha and Kresimir Matkovic and Denis Gracanin and Mario Duras and J. Juric and Helwig Hauser", year = "2007", abstract = "A timing chain drive transfers motion from the engine's crankshaft to the camshaft that operates the valves. The design process of timing chain drives involves computer simulation of many design variants in order to nd an optimum. Most of the simulation results can be represented as families of function graphs (data series). Previously, the analysis of those results was based on static 2D diagrams and animated 3D visualizations. They were suitable for the detailed analysis of a few simulation variants, but not for the comparison of many cases. In this paper we propose a new approach to the analysis based on coordinated linked views and advanced brushing features. Our proposed method supports the interactive analysis of many design variants. We introduce a novel view, called segmented curve view, which can display distributions in families of function graphs. The segmented curve view combines individual function graphs where for a xed value of the independent variable, a bar extends from minimum to maximum values across the family of function graphs. Each bar is divided into segments (bins) with a color that represents the number of function graphs with the value in that segment. In the case study, we demonstrate that the new view combined with “traditional” views provides a strong support for the interactive visual exploration and analysis of a real world timing chain design problem.", month = jul, location = "Zuerich", booktitle = "Proccedings of 5th International Conference on Coordinated & Multiple Views in Exploratory Visualization", URL = "https://www.cg.tuwien.ac.at/research/publications/2007/Konyha_2007_SCV/", } @article{konyha_2006_int, title = "Interactive Visual Analysis of Families of Function Graphs", author = "Zoltan Konyha and Kresimir Matkovic and Denis Gracanin and M. Jelovic and Helwig Hauser", year = "2006", abstract = "The analysis and exploration of multidimensional and multivariate data is still one of the most challenging areas in the  field of visualization. In this paper, we describe an approach to visual analysis of an especially challenging set of problems that exhibit a complex internal data structure. We describe the interactive visual exploration and analysis of data that includes several (usually large) families of function graphs fi(x; t). We describe analysis procedures and practical aspects of the interactive visual analysis specic to this type of data (with emphasis on the function graph characteristic of the data). We adopted the well-proven approach of multiple, linked views with advanced interactive brushing to assess the data. Standard views such as histograms, scatterplots, and parallel coordinates are used to jointly visualize data.We support iterative visual analysis by providing means to create complex, composite brushes that span multiple views and that are constructed using different combination schemes. We demonstrate that engineering applications represent a challenging but very applicable area for visual analytics. As a case study, we describe the optimization of a fuel injection systems in Diesel engines of passenger cars.", month = nov, issn = "1077-2626 ", journal = "IEEE Transaction on Visualization and Computer Graphics", number = "6", volume = "12", pages = "1373--1385", URL = "https://www.cg.tuwien.ac.at/research/publications/2006/konyha_2006_int/", } @phdthesis{Laramee-2004-thesis, title = "Interactive 3D Flow Visualization Based on Textures and Geometric Primitives", author = "Robert S. Laramee", year = "2004", abstract = "This thesis presents research in the area of flow visualization. The theoretical framework is based on the notion that flow visualization methodology can be classified into four main areas: direct, geometric, texture-based, and feature-based flow visualization. Our work focuses on the direct, geometric, and texture-based categories, with special emphasis on texture-based approaches. After presenting the state-of-the-art, we discuss a technique for resampling of CFD simulation data. The resampling tool addresses both the perceptual problems resulting from a brute force hedgehog visualization and flow field coverage problems. These challenges are handled by giving the user control of the resolution of the resampling grid in object space and giving the user precise control of where to place the vector glyphs. Afterward, we present a novel technique for visualization of unsteady flow on surfaces from computational fluid dynamics. The method generates dense representations of time-dependent vector fields with high spatio-temporal correlation. While the 3D vector fields are associated with arbitrary triangular surface meshes, the generation and advection of texture properties is confined to image space. Frame rates of up to 60 frames per second are realized by exploiting graphics card hardware. We apply this algorithm to unsteady flow on boundary surfaces of, large, complex meshes from computational fluid dynamics composed of more than 200,000 polygons, dynamic meshes with time-dependent geometry and topology, as well as medical data. We also apply texture-based flow visualization techniques to isosurfaces. The result is a combination of two well known scientific visualization techniques, namely iso-surfacing and texture-based flow visualization, into a useful hybrid approach. Next we describe our collection of geometric flow visualization techniques including oriented streamlines, streamlets, a streamrunner tool, streamcomets, and a real-time animated streamline technique. We place special emphasis on necessary measures required in order for geometric techniques to be applicable to real-world data sets. In order to demonstrate the use of all techniques, we apply our direct, geometric, and texture-based flow visualization techniques to investigate swirl and tumble motion, two flow patterns found commonly in computational fluid dynamics (CFD). Our work presents a visual analysis of these motions across three spatial domains: 2D slices, 2.5D surfaces, and 3D. ", address = "Favoritenstrasse 9-11/E193-02, A-1040 Vienna, Austria", school = "Institute of Computer Graphics and Algorithms, Vienna University of Technology ", URL = "https://www.cg.tuwien.ac.at/research/publications/2004/Laramee-2004-thesis/", }