| 1. |
- Angelopoulos, Anastasios N., et al.
(författare)
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Event-Based Near-Eye Gaze Tracking Beyond 10,000 Hz
- 2021
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; 27:5, s. 2577-2586
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Tidskriftsartikel (refereegranskat)abstract
- The cameras in modern gaze-tracking systems suffer from fundamental bandwidth and power limitations, constraining data acquisition speed to 300 Hz realistically. This obstructs the use of mobile eye trackers to perform, e.g., low latency predictive rendering, or to study quick and subtle eye motions like microsaccades using head-mounted devices in the wild. Here, we propose a hybrid frame-event-based near-eye gaze tracking system offering update rates beyond 10,000 Hz with an accuracy that matches that of high-end desktop-mounted commercial trackers when evaluated in the same conditions. Our system, previewed in Figure 1, builds on emerging event cameras that simultaneously acquire regularly sampled frames and adaptively sampled events. We develop an online 2D pupil fitting method that updates a parametric model every one or few events. Moreover, we propose a polynomial regressor for estimating the point of gaze from the parametric pupil model in real time. Using the first event-based gaze dataset, we demonstrate that our system achieves accuracies of 0.45 degrees -1.75 degrees for fields of view from 45 degrees to 98 degrees. With this technology, we hope to enable a new generation of ultra-low-latency gaze-contingent rendering and display techniques for virtual and augmented reality.
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| 2. |
- Bae, S. Sandra, et al.
(författare)
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A Computational Design Pipeline to Fabricate Sensing Network Physicalizations
- 2024
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : IEEE COMPUTER SOC. - 1077-2626 .- 1941-0506. ; 30:1, s. 913-923
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Tidskriftsartikel (refereegranskat)abstract
- Interaction is critical for data analysis and sensemaking. However, designing interactive physicalizations is challenging as it requires cross-disciplinary knowledge in visualization, fabrication, and electronics. Interactive physicalizations are typically produced in an unstructured manner, resulting in unique solutions for a specific dataset, problem, or interaction that cannot be easily extended or adapted to new scenarios or future physicalizations. To mitigate these challenges, we introduce a computational design pipeline to 3D print network physicalizations with integrated sensing capabilities. Networks are ubiquitous, yet their complex geometry also requires significant engineering considerations to provide intuitive, effective interactions for exploration. Using our pipeline, designers can readily produce network physicalizations supporting selection-the most critical atomic operation for interaction-by touch through capacitive sensing and computational inference. Our computational design pipeline introduces a new design paradigm by concurrently considering the form and interactivity of a physicalization into one cohesive fabrication workflow. We evaluate our approach using (i) computational evaluations, (ii) three usage scenarios focusing on general visualization tasks, and (iii) expert interviews. The design paradigm introduced by our pipeline can lower barriers to physicalization research, creation, and adoption.
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| 3. |
- Barrera, T, et al.
(författare)
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Faster shading by equal angle interpolation of vectors
- 2004
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1077-2626 .- 1941-0506. ; 10:2, s. 217-223
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we show how spherical linear interpolation can be used to produce shading with a quality at least similar to Phong shading at a computational effort in the inner loop that is close to that of the Gouraud method. We show how to use the Chebyshev's recurrence relation in order to compute the shading very efficiently. Furthermore, it can also be used to interpolate vectors in such a way that normalization is not necessary, which will make the interpolation very fast. The somewhat larger setup effort required by this approach can be handled through table look up techniques.
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| 4. |
- Bergström, Ilias, et al.
(författare)
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The Plausibility of a String Quartet Performance in Virtual Reality
- 2017
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : IEEE COMPUTER SOC. - 1077-2626 .- 1941-0506. ; 23:4, s. 1332-1339
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Tidskriftsartikel (refereegranskat)abstract
- We describe an experiment that explores the contribution of auditory and other features to the illusion of plausibility in a virtual environment that depicts the performance of a string quartet. 'Plausibility' refers to the component of presence that is the illusion that the perceived events in the virtual environment are really happening. The features studied were: Gaze (the musicians ignored the participant, the musicians sometimes looked towards and followed the participant's movements), Sound Spatialization (Mono, Stereo, Spatial), Auralization (no sound reflections, reflections corresponding to a room larger than the one perceived, reflections that exactly matched the virtual room), and Environment (no sound from outside of the room, birdsong and wind corresponding to the outside scene). We adopted the methodology based on color matching theory, where 20 participants were first able to assess their feeling of plausibility in the environment with each of the four features at their highest setting. Then five times participants started from a low setting on all features and were able to make transitions from one system configuration to another until they matched their original feeling of plausibility. From these transitions a Markov transition matrix was constructed, and also probabilities of a match conditional on feature configuration. The results show that Environment and Gaze were individually the most important factors influencing the level of plausibility. The highest probability transitions were to improve Environment and Gaze, and then Auralization and Spatialization. We present this work as both a contribution to the methodology of assessing presence without questionnaires, and showing how various aspects of a musical performance can influence plausibility.
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| 5. |
- Bladin, Kalle, et al.
(författare)
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Globe Browsing: Contextualized Spatio-Temporal Planetary Surface Visualization
- 2018
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; 24:1, s. 802-811
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Tidskriftsartikel (refereegranskat)abstract
- Results of planetary mapping are often shared openly for use in scientific research and mission planning. In its raw format, however, the data is not accessible to non-experts due to the difficulty in grasping the context and the intricate acquisition process. We present work on tailoring and integration of multiple data processing and visualization methods to interactively contextualize geospatial surface data of celestial bodies for use in science communication. As our approach handles dynamic data sources, streamed from online repositories, we are significantly shortening the time between discovery and dissemination of data and results. We describe the image acquisition pipeline, the pre-processing steps to derive a 2.5D terrain, and a chunked level-of-detail, out-of-core rendering approach to enable interactive exploration of global maps and high-resolution digital terrain models. The results are demonstrated for three different celestial bodies. The first case addresses high-resolution map data on the surface of Mars. A second case is showing dynamic processes. such as concurrent weather conditions on Earth that require temporal datasets. As a final example we use data from the New Horizons spacecraft which acquired images during a single flyby of Pluto. We visualize the acquisition process as well as the resulting surface data. Our work has been implemented in the OpenSpace software [8], which enables interactive presentations in a range of environments such as immersive dome theaters. interactive touch tables. and virtual reality headsets.
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| 6. |
- Bock, Alexander, et al.
(författare)
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Coherency-Based Curve Compression for High-Order Finite Element Model Visualization
- 2012
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; 18:12, s. 2315-2324
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Tidskriftsartikel (refereegranskat)abstract
- Finite element (FE) models are frequently used in engineering and life sciences within time-consuming simulations. In contrast with the regular grid structure facilitated by volumetric data sets, as used in medicine or geosciences, FE models are defined over a non-uniform grid. Elements can have curved faces and their interior can be defined through high-order basis functions, which pose additional challenges when visualizing these models. During ray-casting, the uniformly distributed sample points along each viewing ray must be transformed into the material space defined within each element. The computational complexity of this transformation makes a straightforward approach inadequate for interactive data exploration. In this paper, we introduce a novel coherency-based method which supports the interactive exploration of FE models by decoupling the expensive world-to-material space transformation from the rendering stage, thereby allowing it to be performed within a precomputation stage. Therefore, our approach computes view-independent proxy rays in material space, which are clustered to facilitate data reduction. During rendering, these proxy rays are accessed, and it becomes possible to visually analyze high-order FE models at interactive frame rates, even when they are time-varying or consist of multiple modalities. Within this paper, we provide the necessary background about the FE data, describe our decoupling method, and introduce our interactive rendering algorithm. Furthermore, we provide visual results and analyze the error introduced by the presented approach.
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| 7. |
- Bock, Alexander, 1985-, et al.
(författare)
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OpenSpace : A System for Astrographics
- 2020
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; 26:1, s. 633-642
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Tidskriftsartikel (refereegranskat)abstract
- Human knowledge about the cosmos is rapidly increasing as instruments and simulations are generating new data supporting the formation of theory and understanding of the vastness and complexity of the universe. OpenSpace is a software system that takes on the mission of providing an integrated view of all these sources of data and supports interactive exploration of the known universe from the millimeter scale showing instruments on spacecrafts to billions of light years when visualizing the early universe. The ambition is to support research in astronomy and space exploration, science communication at museums and in planetariums as well as bringing exploratory astrographics to the class room. There is a multitude of challenges that need to be met in reaching this goal such as the data variety, multiple spatio-temporal scales, collaboration capabilities, etc. Furthermore, the system has to be flexible and modular to enable rapid prototyping and inclusion of new research results or space mission data and thereby shorten the time from discovery to dissemination. To support the different use cases the system has to be hardware agnostic and support a range of platforms and interaction paradigms. In this paper we describe how OpenSpace meets these challenges in an open source effort that is paving the path for the next generation of interactive astrographics.
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| 8. |
- Bock, Alexander, 1985-, et al.
(författare)
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TopoAngler: Interactive Topology-Based Extraction of Fishes
- 2018
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : IEEE. - 1077-2626 .- 1941-0506. ; 24:1, s. 812-821
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Tidskriftsartikel (refereegranskat)abstract
- We present TopoAngler, a visualization framework that enables an interactive user-guided segmentation of fishes contained in a micro-CT scan. The inherent noise in the CT scan coupled with the often disconnected (and sometimes broken) skeletal structure of fishes makes an automatic segmentation of the volume impractical. To overcome this, our framework combines techniques from computational topology with an interactive visual interface, enabling the human-in-the-Ioop to effectively extract fishes from the volume. In the first step, the join tree of the input is used to create a hierarchical segmentation of the volume. Through the use of linked views, the visual interface then allows users to interactively explore this hierarchy, and gather parts of individual fishes into a coherent sub-volume, thus reconstructing entire fishes. Our framework was primarily developed for its application to CT scans of fishes, generated as part of the ScanAllFish project, through close collaboration with their lead scientist. However, we expect it to also be applicable in other biological applications where a single dataset contains multiple specimen; a common routine that is now widely followed in laboratories to increase throughput of expensive CT scanners.
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| 9. |
- Bodin, Kenneth, et al.
(författare)
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Constraint Fluids
- 2012
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - Los Alamitos, USA : IEEE Computer Society. - 1077-2626 .- 1941-0506. ; 18:3, s. 516-526
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Tidskriftsartikel (refereegranskat)abstract
- We present a fluid simulation method whereincompressibility is enforced through a holonomic constrainton the mass density. The method starts in aLagrangian particle formulation where the mass densityand other field quantities are represented by SmoothedParticle Hydrodynamics (SPH) kernel approximations.The density constraint is formulated as a regularizedmanybody constraint and is equivalent to very highsound speed. The system is integrated using a variationaldiscrete-time scheme, SPOOK, that includesconstraint regularization and stabilization. This constraintformulation of SPH enables systematic multiphysicsintegration, between rigid multibody physicsand fluids, where buoyancy falls out naturally. The fluidmodel results in a linear system of equations, whilemore general multiphysics systems result in a mixedlinear complementarity problem (MLCP) and we solvethese using iterative methods. The results demonstratenear perfect incompressibility, vastly improved stability,allowing for large time steps, and two orders of magnitudeimproved computational performance. Proof ofconcept is given for computer graphics applications andinteractive simulations.
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| 10. |
- Brodersen, Anders, et al.
(författare)
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Geometric Texturing Using Level Sets
- 2008
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Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1077-2626 .- 1941-0506. ; 14:2, s. 277-288
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Tidskriftsartikel (refereegranskat)abstract
- We present techniques for warping and blending (or subtracting) geometric textures onto surfaces represented by high resolution level sets. The geometric texture itself can be represented either explicitly as a polygonal mesh or implicitly as a level set. Unlike previous approaches, we can produce topologically connected surfaces with smooth blending and low distortion. Specifically, we offer two different solutions to the problem of adding fine-scale geometric detail to surfaces. Both solutions assume a level set representation of the base surface which is easily achieved by means of a mesh-to-level-set scan conversion. To facilitate our mapping, we parameterize the embedding space of the base level set surface using fast particle advection. We can then warp explicit texture meshes onto this surface at nearly interactive speeds or blend level set representations of the texture to produce high-quality surfaces with smooth transitions.
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