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Now showing 1 - 10 of 15
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    Interactive Projective Texturing for Non-Photorealistic Shading of Technical 3D Models
    (The Eurographics Association, 2013) Lux, Roland; Trapp, Matthias; Semmo, Amir; Döllner, Jürgen; Silvester Czanner and Wen Tang
    This paper presents a novel interactive rendering technique for creating and editing shadings for man-made objects in technical 3D visualizations. In contrast to shading approaches that use intensities computed based on surface normals (e.g., Phong, Gooch, Toon shading), the presented approach uses one-dimensional gradient textures, which can be parametrized and interactively manipulated based on per-object bounding volume approximations. The fully hardware-accelerated rendering technique is based on projective texture mapping and customizable intensity transfer functions. A provided performance evaluation shows comparable results to traditional normal-based shading approaches. The work also introduce simple direct-manipulation metaphors that enables interactive user control of the gradient texture alignment and intensity transfer functions.
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    Accurate and Marker-less Head Tracking Using Depth Sensors
    (The Eurographics Association, 2013) Breidt, Martin; Bülthoff, Heinrich H.; Curio, Cristóbal; Silvester Czanner and Wen Tang
    Parameterized, high-fidelity 3D surface models can not only be used for rendering animations in the context of Computer Graphics (CG), but have become increasingly popular for analyzing data, and thus making these accessible to CG systems in an Analysis-by-Synthesis loop. In this paper, we utilize this concept for accurate head tracking by fitting a statistical 3D model to marker-less face data acquired with a low-cost depth sensor, and demonstrate its robustness in a challenging car driving scenario. We compute 3D head position and orientation with a mesh-based 3D shape matching algorithm that is independent of person identity and sensor type, and at the same time robust to facial expressions, speech, partial occlusion and illumination changes. Different strategies for obtaining the 3D face model are evaluated, trading off computational complexity and accuracy. Ground truth data for head pose are obtained from simultaneous marker-based tracking. Average tracking errors are below 6mm for head position and below 2.5 for head orientation, demonstrating the system's potential to be used as part of a non-intrusive head tracking system for use in Augmented Reality or driver assistance systems.
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    Towards Analytical Provenance Visualization for Criminal Intelligence Analysis
    (The Eurographics Association, 2016) Islam, Junayed; Anslow, Craig; Xu, Kai; Wong, William; Zhang, Leishi; Cagatay Turkay and Tao Ruan Wan
    In criminal intelligence analysis to complement the information entailed and to enhance transparency of the operations, it demands logs of the individual processing activities within an automated processing system. Management and tracing of such security sensitive analytical information flow originated from tightly coupled visualizations into visual analytic system for criminal intelligence that triggers huge amount of analytical information on a single click, involves design and development challenges. To lead to a believable story by using scientific methods, reasoning for getting explicit knowledge of series of events, sequences and time surrounding interrelationships with available relevant information by using human perception, cognition, reasoning with database operations and computational methods, an analytic visual judgmental support is obvious for criminal intelligence. Our research outlines the requirements and development challenges of such system as well as proposes a generic way of capturing different complex visual analytical states and processes known as analytic provenance. The proposed technique has been tested into a large heterogeneous event-driven visual analytic modular analyst’'s user interface (AUI) of the project VALCRI (Visual Analytics for Sensemaking in Criminal Intelligence) and evaluated by the police intelligence analysts through it's visual state capturing and retracing interfaces. We have conducted several prototype evaluation sessions with the groups of end-users (police intelligence analysts) and found very positive feedback. Our approach provides a generic support for visual judgmental process into a large complex event-driven AUI system for criminal intelligence analysis.
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    Sketching for Real-time Control of Crowd Simulations
    (The Eurographics Association, 2017) Gonzalez, Luis Rene Montana; Maddock, Steve; Tao Ruan Wan and Franck Vidal
    Crowd simulations are used in various fields such as entertainment, training systems and city planning. However, controlling the behaviour of the pedestrians typically involves tuning of the system parameters through trial and error, a time-consuming process relying on knowledge of a potentially complex parameter set. This paper presents an interactive graphical approach to control the simulation by sketching in the simulation environment. The user is able to sketch obstacles to block pedestrians and lines to force pedestrians to follow a specific path, as well as define spawn and exit locations for pedestrians. The obstacles and lines modify the underlying navigation representation and pedestrian trajectories are recalculated in real time. The FLAMEGPU framework is used for the simulation and the game engine Unreal is used for visualisation. We demonstrate the effectiveness of the approach using a range of scenarios, producing interactive editing and frame rates for tens of thousands of pedestrians. A comparison with the commercial software MassMotion is also given.
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    ViewFusion: Correlating Structure and Activity Views for Execution Traces
    (The Eurographics Association, 2012) Trümper, Jonas; Telea, Alexandru; Döllner, Jürgen; Hamish Carr and Silvester Czanner
    Visualization of data on structure and related temporal activity supports the analysis of correlations between the two types of data. This is typically done by linked views. This has shortcomings with respect to efficient space usage and makes mapping the effect of user input into one view into the other view difficult. We propose here a novel, space-efficient technique that 'fuses' the two information spaces - structure and activity - in one view. We base our technique on the idea that user interaction should be simple, yet easy to understand and follow. We apply our technique, implemented in a prototype tool, for the understanding of software engineering datasets, namely static structure and execution traces of the Chromium web browser.
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    Multi-Perspective Detail+Overview Visualization for 3D Building Exploration
    (The Eurographics Association, 2013) Pasewaldt, Sebastian; Trapp, Matthias; Döllner, Jürgen; Silvester Czanner and Wen Tang
    Virtual 3D building models, as key elements of virtual 3D city models, are used in a growing number of application domains, such as geoanalysis, disaster management and architectural planning. Visualization systems for such building models often rely on perspective or orthogonal projections using a single viewpoint. Therefore, the exploration of a complete model requires a user to change the viewpoint multiple times and to memorize the content of each view to obtain a comprehensive mental model. Since this is usually a time-consuming task, which implies context switching, current visualization systems use multiple viewports to simultaneously depict an object from different perspectives. Our approach extends the idea of multiple viewports by combining two linked views for the interactive exploration of virtual 3D buildings model and their façades. In contrast to traditional approaches, we automatically generate a multi-perspective view that simultaneously depicts all façades of the building in one overview image. This facilitates the process of obtaining overviews and supports fast and direct navigation to various points-of-interest. We describe the concept and implementations of our Multiple-Center-of-Projection camera model for real-time multi-perspective image synthesis. Further, we provide insights into different interaction techniques for linked multi-perspective views and outline approaches of future work.
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    12DoF Interaction for Scientific Visualisation
    (The Eurographics Association, 2017) Turner, Martin J.; Morris, Tim; Sandoval, Mario; Tao Ruan Wan and Franck Vidal
    This short extended abstract investigates human-computer interactions in relation to a specific Six Degree of Freedom (6DoF) input device; described is the driver development and calibration required for a novel piece of hardware; and after initial user tests and a questionnaire of satisfaction, we consider areas for further research. This abstract concludes with a discussion of the design and use of dual-6DoF input devices and from feedback how new interaction modes will be exploited.
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    Topological Visualisation Techniques for the Understanding of Lattice Quantum Chromodynamics (LQCD) Simulations
    (The Eurographics Association, 2016) Thomas, Dean P.; Borgo, Rita; Hands, Simon; Cagatay Turkay and Tao Ruan Wan
    The use of topology for visualisation applications has become increasingly popular due to its ability to summarise data at a high level. Criticalities in scalar field data are used by visualisation methods such as the Reeb graph and contour trees to present topological structure in simple graph based formats. These techniques can be used to segment the input field, recognising the boundaries between multiple objects, allowing whole contour meshes to be seeded as separate objects. In this paper we demonstrate the use of topology based techniques when applied to theoretical physics data generated from Quantum Chromodynamics simulations, which due to its structure complicates their use. We also discuss how the output of algorithms involved in topological visualisation can be used by physicists to further their understanding of Quantum Chromodynamics.
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    PED: Pedestrian Environment Designer
    (The Eurographics Association, 2016) McIlveen, James; Maddock, Steve; Heywood, Peter; Richmond, Paul; Cagatay Turkay and Tao Ruan Wan
    Pedestrian simulations have many uses, from pedestrian planning for architecture design through to games and entertainment. However, it is still challenging to efficiently author such simulations, especially for non-technical users. Direct pedestrian control is usually laborious, and, while indirect, environment-level control is often faster, it currently lacks the necessary tools to create complex environments easily and without extensive prior technical knowledge. This paper describes an indirect, environment-level control system in which pedestrians' behaviour can be specified efficiently and then interactively tuned. With the Pedestrian Environment Designer (PED) interface, authors can define environments using tools similar to those found in raster graphics editing software such as PhotoshopTM. Users paint on two-dimensional bitmap layers to control the behaviour of pedestrians in a three-dimensional simulation. The layers are then compiled to produce a live, agent-based pedestrian simulation using the FLAME GPU framework. Entrances and exits can be inserted, collision boundaries defined, and areas of attraction and avoidance added. The system also offers dynamic simulation updates at runtime giving immediate author feedback and enabling authors to simulate scenarios with dynamic elements such as barriers, or dynamic circumstances such as temporary areas of avoidance. As a result, authors are able to create complex crowd simulations more effectively and with minimal training.
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    Fast and Simple Agglomerative LBVH Construction
    (The Eurographics Association, 2014) Apetrei, Ciprian; Rita Borgo and Wen Tang
    This paper continues the long-standing tradition of gradually improving the construction speed of spatial acceleration structures using sorted Morton codes. Previous work on this topic forms a clear sequence where each new paper sheds more light on the nature of the problem and improves the hierarchy generation phase in terms of performance, simplicity, parallelism and generality. Previous approaches constructed the tree by firstly generating the hierarchy and then calculating the bounding boxes of each node by using a bottom-up traversal. Continuing the work, we present an improvement by providing a bottom-up method that finds each node's parent while assigning bounding boxes, thus constructing the tree in linear time in a single kernel launch. Also, our method allows clustering the sorted points using an user-defined distance metric function.