84 results on '"Elmar Eisemann"'
Search Results
2. SalientGaze: Saliency-based gaze correction in virtual reality
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Elmar Eisemann, Peiteng Shi, and Markus Billeter
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Computer science ,business.industry ,Headset ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,General Engineering ,020207 software engineering ,Ranging ,02 engineering and technology ,Virtual reality ,computer.software_genre ,Computer Graphics and Computer-Aided Design ,Gaze ,Rendering (computer graphics) ,Human-Computer Interaction ,Salient ,Virtual machine ,0202 electrical engineering, electronic engineering, information engineering ,Eye tracking ,020201 artificial intelligence & image processing ,Computer vision ,Artificial intelligence ,business ,computer - Abstract
Eye-tracking with gaze estimation is a key element in many applications, ranging from foveated rendering and user interaction to behavioural analysis and usage metrics. For virtual reality, eye-tracking typically relies on near-eye cameras that are mounted in the VR headset. Such methods usually involve an initial calibration to create a mapping from eye features to a gaze position. However, the accuracy based on the initial calibration degrades when the position of the headset relative to the users’ head changes; this is especially noticeable when users readjust the headset for comfort or even completely remove it for a short while. We show that a correction of such shifts can be achieved via 2D drift vectors in eye space. Our method estimates these drifts by extracting salient cues from the shown virtual environment to determine potential gaze directions. Our solution can compensate for HMD shifts, even those arising from taking off the headset, which enables us to eliminate reinitialization steps. more...
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- 2020
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3. Interactively Modifying Compressed Sparse Voxel Representations
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Elmar Eisemann, Markus Billeter, and Victor Careil
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Computer science ,Voxel ,business.industry ,Computer vision ,Artificial intelligence ,computer.software_genre ,business ,Computer Graphics and Computer-Aided Design ,computer ,Computing Methodologies - Published
- 2020
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4. Front Matter
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Elmar Eisemann, Karan Singh, and Fang-Lue Zhang
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Engineering ,business.industry ,Computer graphics (images) ,Graphics ,business ,Computer Graphics and Computer-Aided Design - Published
- 2021
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5. ShutterApp: Spatio‐temporal Exposure Control for Videos
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Nestor Z. Salamon, Markus Billeter, and Elmar Eisemann
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Computational photography (artistic) ,Computer science ,business.industry ,Computer vision ,Exposure control ,Artificial intelligence ,business ,Computer Graphics and Computer-Aided Design ,Computing Methodologies - Published
- 2019
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6. Stochastic-Depth Ambient Occlusion
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Jop Vermeer, Elmar Eisemann, and Leonardo Scandolo
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Spatial stability ,Pixel ,business.industry ,Computer science ,020207 software engineering ,02 engineering and technology ,Computer Graphics and Computer-Aided Design ,Computer Science Applications ,Rendering (computer graphics) ,Ambient occlusion ,Screen-space techniques ,Robustness (computer science) ,Depth map ,Real-time rendering ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Artificial intelligence ,Depth perception ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Ambient occlusion (AO) is a popular rendering technique that enhances depth perception and realism by darkening locations that are less exposed to ambient light (e.g., corners and creases). In real-time applications, screen-space variants, relying on the depth buffer, are used due to their high performance and good visual quality. However, these only take visible surfaces into account, resulting in inconsistencies, especially during motion. Stochastic-Depth Ambient Occlusion is a novel AO algorithm that accounts for occluded geometry by relying on a stochastic depth map, capturing multiple scene layers per pixel at random. Hereby, we efficiently gather missing information in order to improve upon the accuracy and spatial stability of conventional screen-space approximations, while maintaining real-time performance. Our approach integrates well into existing rendering pipelines and improves the robustness of many different AO techniques, including multi-view solutions. more...
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- 2021
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7. Front Matter
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Fang-Lue Zhang, Elmar Eisemann, and Alec Jacobson
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Engineering ,business.industry ,Computer graphics (images) ,Graphics ,business ,Computer Graphics and Computer-Aided Design - Published
- 2020
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8. Multi-scale optical coherence tomography imaging and visualization of Vermeer's Girl with a Pearl Earring
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Jeroen Kalkman, Guusje Harteveld, Abbie Vandivere, Tom Callewaert, Elmar Eisemann, Joris Dik, and Jerry Guo
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Craquelure ,Computer science ,Varnish ,02 engineering and technology ,01 natural sciences ,010309 optics ,Image stitching ,Optics ,Optical coherence tomography ,Computer graphics (images) ,0103 physical sciences ,medicine ,Zoom ,Interactive visualization ,Painting ,medicine.diagnostic_test ,business.industry ,Glaze ,Digital photography ,021001 nanoscience & nanotechnology ,Viewing angle ,Layer thickness ,Atomic and Molecular Physics, and Optics ,Visualization ,OA-Fund TU Delft ,visual_art ,visual_art.visual_art_medium ,0210 nano-technology ,business - Abstract
We demonstrate multi-scale multi-parameter optical coherence tomography (OCT) imaging and visualization of Johannes Vermeer’s painting Girl with a Pearl Earring. Through automated acquisition, OCT image segmentation, and 3D volume stitching we realize OCT imaging at the scale of an entire painting. This makes it possible to image, with micrometer axial and lateral resolution, an entire painting over more than 5 orders of length scale. From the multi-scale OCT data we quantify multiple parameters in a fully automated way: the surface height, the scattering strength, and the combined glaze and varnish layer thickness. The multi-parameter OCT data of Girl with a Pearl Earring shows various features: Vermeer’s brushstrokes, surface craquelure, paint losses, and restorations. Through an interactive visualization of the Girl, based on the OCT data and the optical properties of historical reconstructions of Vermeer’s paint, we can virtually study the effect of the lighting condition, viewing angle, zoom level and presence/absence of glaze layer. The interactive visualization shows various new painting features. It demonstrates that the glaze layer structure and its optical properties were essential to Vermeer to create an extremely strong light to dark contrast between the figure and the background that gives the painting such an iconic aesthetic appeal. more...
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- 2020
9. Next Event Estimation++
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Elmar Eisemann, Martin Eisemann, and Jerry Jinfeng Guo
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shadowray ,Computer science ,• Computing methodologies → Ray tracing ,02 engineering and technology ,computer.software_genre ,Metropolis light transport ,Rendering (computer graphics) ,Voxel ,0202 electrical engineering, electronic engineering, information engineering ,Computer vision ,Visibility ,path tracing ,ComputingMethodologies_COMPUTERGRAPHICS ,CCS Concepts ,business.industry ,Visibility (geometry) ,Sampling (statistics) ,020207 software engineering ,Computer Graphics and Computer-Aided Design ,Path (graph theory) ,Path tracing ,020201 artificial intelligence & image processing ,rendering ,Artificial intelligence ,business ,computer ,bi-directional path tracing ,Importance sampling - Abstract
Monte-Carlo rendering requires determining the visibility between scene points as the most common and compute intense operation to establish paths between camera and light source. Unfortunately, many tests reveal occlusions and the corresponding paths do not contribute to the final image. In this work, we present next event estimation++ (NEE++): a visibility mapping technique to perform visibility tests in a more informed way by caching voxel to voxel visibility probabilities. We show two scenarios: Russian roulette style rejection of visibility tests and direct importance sampling of the visibility. We show applications to next event estimation and light sampling in a uni-directional path tracer, and light-subpath sampling in Bi-Directional Path Tracing. The technique is simple to implement, easy to add to existing rendering systems, and comes at almost no cost, as the required information can be directly extracted from the rendering process itself. It discards up to 80% of visibility tests on average, while reducing variance by 20% compared to other state-of-the-art light sampling techniques with the same number of samples. It gracefully handles complex scenes with efficiency similar to Metropolis light transport techniques but with a more uniform convergence. more...
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- 2020
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10. CNNs on Surfaces using Rotation-Equivariant Features
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Klaus Hildebrandt, Elmar Eisemann, and Ruben Wiersma
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Surface (mathematics) ,Computational Geometry (cs.CG) ,FOS: Computer and information sciences ,Computer Science - Machine Learning ,Computer science ,Computer Vision and Pattern Recognition (cs.CV) ,Coordinate system ,Computer Science - Computer Vision and Pattern Recognition ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,02 engineering and technology ,Curvature ,Topology ,Convolutional neural network ,Convolution ,surface networks ,Machine Learning (cs.LG) ,0202 electrical engineering, electronic engineering, information engineering ,Tangent space ,shape correspondence ,circular Harmonic Filters ,I.2.10 ,I.3.5 ,ComputingMethodologies_COMPUTERGRAPHICS ,business.industry ,Deep learning ,020207 software engineering ,rotation-equivariance ,Filter (signal processing) ,shape classification ,Computer Graphics and Computer-Aided Design ,shape segmentation ,Harmonic function ,geometric deep learning ,Computer Science - Computational Geometry ,Equivariant map ,Artificial intelligence ,CNNs on surfaces ,business - Abstract
This paper is concerned with a fundamental problem in geometric deep learning that arises in the construction of convolutional neural networks on surfaces. Due to curvature, the transport of filter kernels on surfaces results in a rotational ambiguity, which prevents a uniform alignment of these kernels on the surface. We propose a network architecture for surfaces that consists of vector-valued, rotation-equivariant features. The equivariance property makes it possible to locally align features, which were computed in arbitrary coordinate systems, when aggregating features in a convolution layer. The resulting network is agnostic to the choices of coordinate systems for the tangent spaces on the surface. We implement our approach for triangle meshes. Based on circular harmonic functions, we introduce convolution filters for meshes that are rotation-equivariant at the discrete level. We evaluate the resulting networks on shape correspondence and shape classifications tasks and compare their performance to other approaches., Comment: 12 pages, 14 figures, 5 tables, to be published in ACM ToG (SIGGRAPH 2020) more...
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- 2020
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11. GPGPU Linear Complexity t-SNE Optimization
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Boudewijn P. F. Lelieveldt, Julian Thijssen, Elmar Eisemann, Thomas Höllt, Anna Vilanova, Alexander Mordvintsev, Nicola Pezzotti, Baldur van Lew, Algorithms, Geometry and Applications, Visualization, and EAISI Health more...
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FOS: Computer and information sciences ,Computer Science - Machine Learning ,Linear programming ,Computational complexity theory ,Computer Science - Artificial Intelligence ,Computer science ,Computation ,Graphics hardware ,Machine Learning (stat.ML) ,Progressive Visual Analytics ,High Dimensional Data ,Machine Learning (cs.LG) ,Kernel (linear algebra) ,Data visualization ,Statistics - Machine Learning ,Dimensionality Reduction ,business.industry ,GPGPU ,Approximation algorithm ,Computer Graphics and Computer-Aided Design ,Artificial Intelligence (cs.AI) ,Data point ,Approximate Computation ,Signal Processing ,Computer Vision and Pattern Recognition ,General-purpose computing on graphics processing units ,business ,Algorithm ,Software - Abstract
In recent years the t-distributed Stochastic Neighbor Embedding (t-SNE) algorithm has become one of the most used and insightful techniques for exploratory data analysis of high-dimensional data. It reveals clusters of high-dimensional data points at different scales while only requiring minimal tuning of its parameters. However, the computational complexity of the algorithm limits its application to relatively small datasets. To address this problem, several evolutions of t-SNE have been developed in recent years, mainly focusing on the scalability of the similarity computations between data points. However, these contributions are insufficient to achieve interactive rates when visualizing the evolution of the t-SNE embedding for large datasets. In this work, we present a novel approach to the minimization of the t-SNE objective function that heavily relies on graphics hardware and has linear computational complexity. Our technique decreases the computational cost of running t-SNE on datasets by orders of magnitude and retains or improves on the accuracy of past approximated techniques. We propose to approximate the repulsive forces between data points by splatting kernel textures for each data point. This approximation allows us to reformulate the t-SNE minimization problem as a series of tensor operations that can be efficiently executed on the graphics card. An efficient implementation of our technique is integrated and available for use in the widely used Google TensorFlow.js, and an open-source C++ library. more...
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- 2020
12. LightGuider: Guiding interactive lighting design using suggestions, provenance, and quality visualization
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Andreas Walch, Elmar Eisemann, Christian Luksch, Michael Schwärzler, and Theresia Gschwandtner
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FOS: Computer and information sciences ,Computer science ,business.industry ,lighting design ,020207 software engineering ,02 engineering and technology ,Solid modeling ,3D modeling ,Interactive lighting ,Computer Graphics and Computer-Aided Design ,Graphics (cs.GR) ,Visualization ,Computer Science - Graphics ,Data visualization ,Workflow ,global illumination ,Provenance ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,Guidance ,Computer Vision and Pattern Recognition ,business ,Software engineering ,Software - Abstract
LightGuider is a novel guidance-based approach to interactive lighting design, which typically consists of interleaved 3D modeling operations and light transport simulations. Rather than having designers use a trial-And-error approach to match their illumination constraints and aesthetic goals, LightGuider supports the process by simulating potential next modeling steps that can deliver the most significant improvements. LightGuider takes predefined quality criteria and the current focus of the designer into account to visualize suggestions for lighting-design improvements via a specialized provenance tree. This provenance tree integrates snapshot visualizations of how well a design meets the given quality criteria weighted by the designer's preferences. This integration facilitates the analysis of quality improvements over the course of a modeling workflow as well as the comparison of alternative design solutions. We evaluate our approach with three lighting designers to illustrate its usefulness. more...
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- 2020
13. Gradient‐Guided Local Disparity Editing
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Elmar Eisemann, Pablo Bauszat, and Leonardo Scandolo
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shadowing and texture ,business.industry ,Computer science ,image/video editing ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,modelling interfaces ,020207 software engineering ,Stereoscopy ,02 engineering and technology ,Computer Graphics and Computer-Aided Design ,law.invention ,modelling ,image-based modelling ,law ,image and video processing ,0202 electrical engineering, electronic engineering, information engineering ,I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism–Colour ,020201 artificial intelligence & image processing ,Computer vision ,Shading ,Artificial intelligence ,Depth perception ,business ,shading ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Stereoscopic 3D technology gives visual content creators a new dimension of design when creating images and movies. While useful for conveying emotion, laying emphasis on certain parts of the scene, or guiding the viewer's attention, editing stereo content is a challenging task. Not respecting comfort zones or adding incorrect depth cues, for example depth inversion, leads to a poor viewing experience. In this paper, we present a solution for editing stereoscopic content that allows an artist to impose disparity constraints and removes resulting depth conflicts using an optimization scheme. Using our approach, an artist only needs to focus on important high-level indications that are automatically made consistent with the entire scene while avoiding contradictory depth cues and respecting viewer comfort. more...
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- 2018
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14. Quad-Based Fourier Transform for Efficient Diffraction Synthesis
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Leonardo Scandolo, Sungkil Lee, and Elmar Eisemann
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Diffraction ,symbols.namesake ,Fourier transform ,Materials science ,Optics ,business.industry ,0202 electrical engineering, electronic engineering, information engineering ,symbols ,020206 networking & telecommunications ,020207 software engineering ,02 engineering and technology ,business ,Computer Graphics and Computer-Aided Design - Published
- 2018
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15. Effects of inter-reflections in box spaces on perceived object color harmony and shape
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Maarten W. A. Wijntjes, Jan Jaap R. van Assen, Sylvia C. Pont, Elmar Eisemann, and Cehao Yu
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Ophthalmology ,Harmony (color) ,Object color ,Computer science ,business.industry ,Computer vision ,Artificial intelligence ,business ,Sensory Systems - Published
- 2021
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16. Perception-driven Accelerated Rendering
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Karol Myszkowski, Thorsten Roth, Michael Stengel, Martin Weier, André Hinkenjann, Piotr Didyk, Elmar Eisemann, Philipp Slusallek, Marcus Magnor, Ernst Kruijff, Martin Eisemann, and Steve Grogorick
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Pixel ,Global illumination ,Computer science ,business.industry ,Motion blur ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,020207 software engineering ,02 engineering and technology ,Computer Graphics and Computer-Aided Design ,Rendering (computer graphics) ,Refresh rate ,Computer graphics ,Digital image ,Gamut ,Computer graphics (images) ,Color depth ,Human visual system model ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Depth of field ,Artificial intelligence ,business ,High dynamic range ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Advances in computer graphics enable us to create digital images of astonishing complexity and realism. However, processing resources are still a limiting factor. Hence, many costly but desirable aspects of realism are often not accounted for, including global illumination, accurate depth of field and motion blur, spectral effects, etc. especially in real-time rendering. At the same time, there is a strong trend towards more pixels per display due to larger displays, higher pixel densities or larger fields of view. Further observable trends in current display technology include more bits per pixel high dynamic range, wider color gamut/fidelity, increasing refresh rates better motion depiction, and an increasing number of displayed views per pixel stereo, multi-view, all the way to holographic or lightfield displays. These developments cause significant unsolved technical challenges due to aspects such as limited compute power and bandwidth. Fortunately, the human visual system has certain limitations, which mean that providing the highest possible visual quality is not always necessary. In this report, we present the key research and models that exploit the limitations of perception to tackle visual quality and workload alike. Moreover, we present the open problems and promising future research targeting the question of how we can minimize the effort to compute and display only the necessary pixels while still offering a user full visual experience. more...
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- 2017
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17. Computational Light Painting Using a Virtual Exposure
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Nestor Z. Salamon, Marcel Lancelle, and Elmar Eisemann
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Computer science ,business.industry ,Shot (filmmaking) ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,020207 software engineering ,02 engineering and technology ,Animation ,Computer Graphics and Computer-Aided Design ,Computer graphics (images) ,0202 electrical engineering, electronic engineering, information engineering ,Light painting ,020201 artificial intelligence & image processing ,Computer vision ,Artificial intelligence ,business ,3D computer graphics ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Light painting is an artform where a light source is moved during a long-exposure shot, creating trails resembling a stroke on a canvas. It is very difficult to perform because the light source needs to be moved at the intended speed and along a precise trajectory. Additionally, images can be corrupted by the person moving the light. We propose computational light painting, which avoids such artifacts and is easy to use. Taking a video of the moving light as input, a virtual exposure allows us to draw the intended light positions in a post-process. We support animation, as well as 3D light sculpting, with high-quality results. more...
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- 2017
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18. Indoor Scene Reconstruction Using Near-Light Photometric Stereo
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Jingtang Liao, Pablo Bauszat, Elmar Eisemann, Bert Buchholz, and Jean-Marc Thiery
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business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,020207 software engineering ,02 engineering and technology ,Iterative reconstruction ,Computer Graphics and Computer-Aided Design ,Hough transform ,law.invention ,Photometric stereo ,Light source ,Robustness (computer science) ,law ,Outlier ,0202 electrical engineering, electronic engineering, information engineering ,Image noise ,020201 artificial intelligence & image processing ,Computer vision ,Specular reflection ,Artificial intelligence ,business ,Software ,ComputingMethodologies_COMPUTERGRAPHICS ,Mathematics - Abstract
We propose a novel framework for photometric stereo (PS) under low-light conditions using uncalibrated near-light illumination. It operates on free-form video sequences captured with a minimalistic and affordable setup. We address issues such as albedo variations, shadowing, perspective projections, and camera noise. Our method uses specular spheres detected with a perspective-correcting Hough transform to robustly triangulate light positions in the presence of outliers via a least-squares approach. Furthermore, we propose an iterative reweighting scheme in combination with an $\ell _{p}$ -norm minimizer to robustly solve the calibrated near-light PS problem. In contrast to other approaches, our framework reconstructs depth, albedo (relative to light source intensity), and normals simultaneously and is demonstrated on synthetic and real-world scenes. more...
- Published
- 2017
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19. Compressed Multiresolution Hierarchies for High-Quality Precomputed Shadows
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Leonardo Scandolo, Pablo Bauszat, and Elmar Eisemann
- Subjects
Lossless compression ,Texture compression ,Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,020207 software engineering ,02 engineering and technology ,Computer Graphics and Computer-Aided Design ,Real-time computer graphics ,Computer graphics ,Tree (data structure) ,Depth map ,S3 Texture Compression ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Shading ,Artificial intelligence ,Shadow mapping ,Quantization (image processing) ,business ,3D computer graphics ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
The quality of shadow mapping is traditionally limited by texture resolution. We present a novel lossless compression scheme for high-resolution shadow maps based on precomputed multiresolution hierarchies. Traditional multiresolution trees can compactly represent homogeneous regions of shadow maps at coarser levels, but require many nodes for fine details. By conservatively adapting the depth map, we can significantly reduce the tree complexity. Our proposed method offers high compression rates, avoids quantization errors, exploits coherency along all data dimensions, and is well-suited for GPU architectures. Our approach can be applied for coherent shadow maps as well, enabling several applications, including high-quality soft shadows and dynamic lights moving on fixed-trajectories. more...
- Published
- 2016
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20. Geometry and Attribute Compression for Voxel Scenes
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Jean-Marc Thiery, Elmar Eisemann, Pablo Bauszat, Timothy R. Kol, and Bas Dado
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business.industry ,Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Palette (computing) ,020207 software engineering ,Geometry ,02 engineering and technology ,computer.software_genre ,Computer Graphics and Computer-Aided Design ,Real-time computer graphics ,Reduction (complexity) ,Voxel ,Compression (functional analysis) ,Ray casting ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Ray tracing (graphics) ,Computer vision ,Artificial intelligence ,business ,computer ,3D computer graphics ,ComputingMethodologies_COMPUTERGRAPHICS ,Volume (compression) - Abstract
Voxel-based approaches are today's standard to encode volume data. Recently, directed acyclic graphs (DAGs) were successfully used for compressing sparse voxel scenes as well, but they are restricted to a single bit of (geometry) information per voxel. We present a method to compress arbitrary data, such as colors, normals, or reflectance information. By decoupling geometry and voxel data via a novel mapping scheme, we are able to apply the DAG principle to encode the topology, while using a palette-based compression for the voxel attributes, leading to a drastic memory reduction. Our method outperforms existing state-of-the-art techniques and is well-suited for GPU architectures. We achieve real-time performance on commodity hardware for colored scenes with up to 17 hierarchical levels (a 128K3 voxel resolution), which are stored fully in core. more...
- Published
- 2016
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21. Orientation-Enhanced Parallel Coordinate Plots
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Renata Georgia Raidou, Anna Vilanova, Marcel Breeuwer, Martin Eisemann, Elmar Eisemann, Medical Image Analysis, and Visualization
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business.industry ,Computer science ,020207 software engineering ,02 engineering and technology ,computer.software_genre ,Data structure ,Computer Graphics and Computer-Aided Design ,Visualization ,Data visualization ,Kernel (image processing) ,Histogram ,Signal Processing ,Outlier ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer Vision and Pattern Recognition ,Data mining ,business ,computer ,Software ,Parallel coordinates - Abstract
Parallel Coordinate Plots (PCPs) is one of the most powerful techniques for the visualization of multivariate data. However, for large datasets, the representation suffers from clutter due to overplotting. In this case, discerning the underlying data information and selecting specific interesting patterns can become difficult. We propose a new and simple technique to improve the display of PCPs by emphasizing the underlying data structure. Our Orientation-enhanced Parallel Coordinate Plots (OPCPs) improve pattern and outlier discernibility by visually enhancing parts of each PCP polyline with respect to its slope. This enhancement also allows us to introduce a novel and efficient selection method, the Orientation-enhanced Brushing (O-Brushing). Our solution is particularly useful when multiple patterns are present or when the view on certain patterns is obstructed by noise. We present the results of our approach with several synthetic and real-world datasets. Finally, we conducted a user evaluation, which verifies the advantages of the OPCPs in terms of discernibility of information in complex data. It also confirms that O-Brushing eases the selection of data patterns in PCPs and reduces the amount of necessary user interactions compared to state-of-the-art brushing techniques. more...
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- 2016
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22. Controllable Motion-Blur Effects in Still Images
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Nestor Z. Salamon, Xuejiao Luo, and Elmar Eisemann
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Computer science ,media_common.quotation_subject ,Illusion ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Image processing ,02 engineering and technology ,Object motion ,0202 electrical engineering, electronic engineering, information engineering ,Computer vision ,long exposure ,media_common ,ComputingMethodologies_COMPUTERGRAPHICS ,business.industry ,Motion blur ,020207 software engineering ,Image segmentation ,Computer Graphics and Computer-Aided Design ,Post-production ,image processing ,Kernel (image processing) ,Signal Processing ,post-production ,Computer Vision and Pattern Recognition ,Artificial intelligence ,business ,Software - Abstract
Motion blur in a photo is the consequence of object motion during the image acquisition. It results in a visible trail along the motion of a recorded object and can be used by photographers to convey a sense of motion. Nevertheless, it is very challenging to acquire this effect as intended and requires much experience from the photographer. To achieve actual control over the motion blur, one could be added in a post process but current solutions require complex manual intervention and can lead to artifacts that mix moving and static objects incorrectly. In this paper, we propose a novel method to add motion blur to a single image that generates the illusion of a photographed motion. Relying on a minimal user input, a filtering process is employed to produce a virtual motion effect. It carefully handles object boundaries to avoid artifacts produced by standard filtering methods. We illustrate the effectiveness of our solution with various complex examples, including multi-directional blur, reflections, multiple objects, and illustrate how several motion-related artistic effects can be achieved. Our post-processing solution is an alternative to capturing the intended real-world motion blur directly and enables fine-grained control of the motion-blur effect. more...
- Published
- 2018
23. Smooth Probabilistic Ambient Occlusion for Volume Rendering
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Elmar Eisemann, Thomas Kroes, and Dirk Schut
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business.industry ,Computer science ,Probabilistic logic ,Ambient occlusion ,Computer vision ,Volume rendering ,Artificial intelligence ,business - Published
- 2018
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24. DeepEyes: Progressive Visual Analytics for Designing Deep Neural Networks
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Anna Vilanova, Thomas Höllt, Nicola Pezzotti, Elmar Eisemann, Jan C. van Gemert, and Boudewijn P. F. Lelieveldt
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Visual analytics ,Computer science ,02 engineering and technology ,Machine learning ,computer.software_genre ,Progressive visual analytics ,0202 electrical engineering, electronic engineering, information engineering ,Network architecture ,Artificial neural network ,Time delay neural network ,business.industry ,Deep learning ,020207 software engineering ,Computer Graphics and Computer-Aided Design ,machine learning ,Kernel (image processing) ,deep neural networks ,Independent set ,Signal Processing ,020201 artificial intelligence & image processing ,Computer Vision and Pattern Recognition ,Data mining ,Artificial intelligence ,business ,computer ,Software ,Nervous system network models - Abstract
Deep neural networks are now rivaling human accuracy in several pattern recognition problems. Compared to traditional classifiers, where features are handcrafted, neural networks learn increasingly complex features directly from the data. Instead of handcrafting the features, it is now the network architecture that is manually engineered. The network architecture parameters such as the number of layers or the number of filters per layer and their interconnections are essential for good performance. Even though basic design guidelines exist, designing a neural network is an iterative trial-and-error process that takes days or even weeks to perform due to the large datasets used for training. In this paper, we present DeepEyes, a Progressive Visual Analytics system that supports the design of neural networks during training. We present novel visualizations, supporting the identification of layers that learned a stable set of patterns and, therefore, are of interest for a detailed analysis. The system facilitates the identification of problems, such as superfluous filters or layers, and information that is not being captured by the network. We demonstrate the effectiveness of our system through multiple use cases, showing how a trained network can be compressed, reshaped and adapted to different problems. more...
- Published
- 2018
25. Depth Annotations
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Elmar Eisemann, Shuheng Shen, and Jingtang Liao
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Diffusion (acoustics) ,Computer science ,business.industry ,General Engineering ,Palette (computing) ,020207 software engineering ,Context (language use) ,02 engineering and technology ,Computer Graphics and Computer-Aided Design ,Pipeline (software) ,Human-Computer Interaction ,Depth map ,A single image ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Depth of field ,Artificial intelligence ,Depth-based effects ,Wiggle stereoscopy ,business ,Depth map design ,Unsharp masking - Abstract
We present a novel pipeline to generate a depth map from a single image that can be used as input for a variety of artistic depth-based effects. In such a context, the depth maps do not have to be perfect but are rather designed with respect to a desired result. Consequently, our solution centers around user interaction and relies on a scribble-based depth editing. The annotations can be sparse, as the depth map is generated by a diffusion process, which is guided by image features. We support a variety of controls, such as a non-linear depth mapping, a steering mechanism for the diffusion (e.g., directionality, emphasis, or reduction of the influence of image cues), and besides absolute, we also support relative depth indications. In case that a depth estimate is available from an automatic solution, we illustrate how this information can be integrated in form of a depth palette, that allows the user to transfer depth values via a painting metaphor. We demonstrate a variety of artistic 3D results, including wiggle stereoscopy, artistic abstractions, haze, unsharp masking, and depth of field. more...
- Published
- 2018
26. Applying Visual Analytics to Physically Based Rendering
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Tobias Rapp, Victor Petitjean, Hendrik P. A. Lensch, Sebastian Herholz, Carsten Dachsbacher, Gerard Simons, Elmar Eisemann, Marco Ament, and Martin Eisemann
- Subjects
Visual analytics ,Global illumination ,Computer science ,business.industry ,020207 software engineering ,02 engineering and technology ,visual analytics ,Computer Graphics and Computer-Aided Design ,Visualization ,Rendering (computer graphics) ,Information visualization ,Interactivity ,global illumination ,Histogram ,Computer graphics (images) ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,rendering ,Physically based rendering ,business ,visualization - Abstract
Physically based rendering is a well-understood technique to produce realistic-looking images. However, different algorithms exist for efficiency reasons, which work well in certain cases but fail or produce rendering artefacts in others. Few tools allow a user to gain insight into the algorithmic processes. In this work, we present such a tool, which combines techniques from information visualization and visual analytics with physically based rendering. It consists of an interactive parallel coordinates plot, with a built-in sampling-based data reduction technique to visualize the attributes associated with each light sample. Twodimensional (2D) and three-dimensional (3D) heat maps depict any desired property of the rendering process. An interactively rendered 3D view of the scene displays animated light paths based on the user’s selection to gain further insight into the rendering process. The provided interactivity enables the user to guide the rendering process for more efficiency. To show its usefulness, we present several applications based on our tool. This includes differential light transport visualization to optimize light setup in a scene, finding the causes of and resolving rendering artefacts, such as fireflies, as well as a path length contribution histogram to evaluate the efficiency of different Monte Carlo estimators. more...
- Published
- 2018
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27. Modeling Luminance Perception at Absolute Threshold
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Tobias Ritschel, Petr Kellnhofer, Elmar Eisemann, Karol Myszkowski, and Hans-Peter Seidel
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business.industry ,Computer science ,media_common.quotation_subject ,Quantum noise ,Absolute threshold ,Computer Graphics and Computer-Aided Design ,Luminance ,Retinal rods ,medicine.anatomical_structure ,Perception ,medicine ,Human eye ,Computer vision ,Artificial intelligence ,Scotopic vision ,business ,Noise (radio) ,Hue ,media_common ,Photopic vision - Abstract
When human luminance perception operates close to its absolute threshold, i. e., the lowest perceivable absolute values, appearance changes substantially compared to common photopic or scotopic vision. In particular, most observers report perceiving temporally-varying noise. Two reasons are physiologically plausible; quantum noise (due to the low absolute number of photons) and spontaneous photochemical reactions. Previously, static noise with a normal distribution and no account for absolute values was combined with blue hue shift and blur to simulate scotopic appearance on a photopic display for movies and interactive applications (e.g., games). We present a computational model to reproduce the specific distribution and dynamics of "scotopic noise" for specific absolute values. It automatically introduces a perceptually-calibrated amount of noise for a specific luminance level and supports animated imagery. Our simulation runs in milliseconds at HD resolution using graphics hardware and favorably compares to simpler alternatives in a perceptual experiment. more...
- Published
- 2015
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28. Temporal Video Filtering and Exposure Control for Perceptual Motion Blur
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Marcus Magnor, Martin Eisemann, Pablo Bauszat, Michael Stengel, and Elmar Eisemann
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Retina ,Computer science ,business.industry ,media_common.quotation_subject ,Motion blur ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Video camera ,Computer Graphics and Computer-Aided Design ,Motion (physics) ,law.invention ,medicine.anatomical_structure ,law ,Shutter ,Perception ,Signal Processing ,medicine ,Eye tracking ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Motion interpolation ,business ,Software ,ComputingMethodologies_COMPUTERGRAPHICS ,media_common - Abstract
We propose the computation of a perceptual motion blur in videos. Our technique takes the predicted eye motion into account when watching the video. Compared to traditional motion blur recorded by a video camera our approach results in a perceptual blur that is closer to reality. This postprocess can also be used to simulate different shutter effects or for other artistic purposes. It handles real and artificial video input, is easy to compute and has a low additional cost for rendered content. We illustrate its advantages in a user study using eye tracking. more...
- Published
- 2015
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29. Numerical optimization of alignment reproducibility for customizable surgical guides
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Elmar Eisemann, Edward R. Valstar, and Thomas Kroes
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Male ,Physical simulation ,Rotation ,Computer science ,Customizable surgical guide ,Biomedical Engineering ,Health Informatics ,Translation (geometry) ,030218 nuclear medicine & medical imaging ,Domain (software engineering) ,Set (abstract data type) ,03 medical and health sciences ,0302 clinical medicine ,Knee replacement surgery ,Humans ,Orthopedic Procedures ,Radiology, Nuclear Medicine and imaging ,Computer vision ,Femur ,Genetic optimization ,Simulation ,ComputingMethodologies_COMPUTERGRAPHICS ,Surgical navigation device ,030222 orthopedics ,Reproducibility ,Preoperative planning ,Optimization algorithm ,business.industry ,Reproducibility of Results ,General Medicine ,Computer Graphics and Computer-Aided Design ,Computer Science Applications ,Genetic algorithm optimization ,Task (computing) ,Surgery, Computer-Assisted ,Radiology Nuclear Medicine and imaging ,Female ,Original Article ,Surgery ,Computer Vision and Pattern Recognition ,Artificial intelligence ,business ,Algorithms - Abstract
Purpose Computer-assisted orthopedic surgery aims at minimizing invasiveness, postoperative pain, and morbidity with computer-assisted preoperative planning and intra-operative guidance techniques, of which camera-based navigation and patient-specific templates (PST) are the most common. PSTs are one-time templates that guide the surgeon initially in cutting slits or drilling holes. This method can be extended to reusable and customizable surgical guides (CSG), which can be adapted to the patients’ bone. Determining the right set of CSG input parameters by hand is a challenging task, given the vast amount of input parameter combinations and the complex physical interaction between the PST/CSG and the bone. Methods This paper introduces a novel algorithm to solve the problem of choosing the right set of input parameters. Our approach predicts how well a CSG instance is able to reproduce the planned alignment based on a physical simulation and uses a genetic optimization algorithm to determine optimal configurations. We validate our technique with a prototype of a pin-based CSG and nine rapid prototyped distal femora. Results The proposed optimization technique has been compared to manual optimization by experts, as well as participants with domain experience. Using the optimization technique, the alignment errors remained within practical boundaries of 1.2 mm translation and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0.9^\circ $$\end{document}0.9∘ rotation error. In all cases, the proposed method outperformed manual optimization. Conclusions Manually optimizing CSG parameters turns out to be a counterintuitive task. Even after training, subjects with and without anatomical background fail in choosing appropriate CSG configurations. Our optimization algorithm ensures that the CSG is configured correctly, and we could demonstrate that the intended alignment of the CSG is accurately reproduced on all tested bone geometries. more...
- Published
- 2015
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30. Visual analysis of mass cytometry data by hierarchical stochastic neighbour embedding reveals rare cell types
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Na Li, Boudewijn P. F. Lelieveldt, Vincent van Unen, Frits Koning, Anna Vilanova, Nicola Pezzotti, Marcel J. T. Reinders, Thomas Höllt, and Elmar Eisemann
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CD4-Positive T-Lymphocytes ,0301 basic medicine ,Databases, Factual ,Gastrointestinal Diseases ,Computer science ,Science ,Immunology ,Cytological Techniques ,General Physics and Astronomy ,Bioinformatics ,Article ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Antigens, CD ,T-Lymphocyte Subsets ,Feature (machine learning) ,Humans ,Mass cytometry ,Lymphocytes ,Limit (mathematics) ,lcsh:Science ,Image Cytometry ,Stochastic Processes ,Multidisciplinary ,Hierarchy (mathematics) ,business.industry ,Dimensionality reduction ,Pattern recognition ,General Chemistry ,Flow Cytometry ,Computational biology and bioinformatics ,030104 developmental biology ,Scalability ,Embedding ,lcsh:Q ,Artificial intelligence ,Single-Cell Analysis ,business ,Algorithms ,Biomarkers - Abstract
Mass cytometry allows high-resolution dissection of the cellular composition of the immune system. However, the high-dimensionality, large size, and non-linear structure of the data poses considerable challenges for the data analysis. In particular, dimensionality reduction-based techniques like t-SNE offer single-cell resolution but are limited in the number of cells that can be analyzed. Here we introduce Hierarchical Stochastic Neighbor Embedding (HSNE) for the analysis of mass cytometry data sets. HSNE constructs a hierarchy of non-linear similarities that can be interactively explored with a stepwise increase in detail up to the single-cell level. We apply HSNE to a study on gastrointestinal disorders and three other available mass cytometry data sets. We find that HSNE efficiently replicates previous observations and identifies rare cell populations that were previously missed due to downsampling. Thus, HSNE removes the scalability limit of conventional t-SNE analysis, a feature that makes it highly suitable for the analysis of massive high-dimensional data sets., Single cell profiling yields high dimensional data of very large numbers of cells, posing challenges of visualization and analysis. Here the authors introduce a method for analysis of mass cytometry data that can handle very large datasets and allows their intuitive and hierarchical exploration. more...
- Published
- 2017
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31. Subtle gaze guidance for immersive environments
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Marcus Magnor, Steve Grogorick, Michael Stengel, and Elmar Eisemann
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Visual search ,Computer science ,business.industry ,05 social sciences ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Optical head-mounted display ,020207 software engineering ,02 engineering and technology ,Virtual reality ,computer.software_genre ,Gaze ,Visual field ,Virtual machine ,0202 electrical engineering, electronic engineering, information engineering ,Eye tracking ,0501 psychology and cognitive sciences ,Computer vision ,Artificial intelligence ,business ,computer ,050107 human factors ,Perceptual study - Abstract
Immersive displays allow presentation of rich video content over a wide field of view. We present a method to boost visual importance for a selected - possibly invisible - scene part in a cluttered virtual environment. This desirable feature enables to unobtrusively guide the gaze direction of a user to any location within the immersive 360° surrounding. Our method is based on subtle gaze direction which did not include head rotations in previous work. For covering the full 360° environment and wide field of view, we contribute an approach for dynamic stimulus positioning and shape variation based on eccentricity to compensate for visibility differences across the visual field. Our approach is calibrated in a perceptual study for a head-mounted display with binocular eye tracking. An additional study validates the method within an immersive visual search task. more...
- Published
- 2017
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32. Approximated and user steerable tSNE for progressive visual analytics
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Elmar Eisemann, Thomas Höllt, Anna Vilanova, Laurens van der Maaten, Nicola Pezzotti, Boudewijn P. F. Lelieveldt, Medical Image Analysis, and Visualization
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0301 basic medicine ,FOS: Computer and information sciences ,Visual analytics ,Computer science ,High dimensional data ,media_common.quotation_subject ,Computer Vision and Pattern Recognition (cs.CV) ,Approximate computation ,Computer Science - Computer Vision and Pattern Recognition ,02 engineering and technology ,Machine learning ,computer.software_genre ,Machine Learning (cs.LG) ,03 medical and health sciences ,Text mining ,Data visualization ,Interactive visual analysis ,Progressive visual analytics ,0202 electrical engineering, electronic engineering, information engineering ,media_common ,Creative visualization ,business.industry ,Dimensionality reduction ,Approximation algorithm ,020207 software engineering ,Computer Graphics and Computer-Aided Design ,Visualization ,Computer Science - Learning ,030104 developmental biology ,Analytics ,Signal Processing ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Data mining ,business ,computer ,Software - Abstract
Progressive Visual Analytics aims at improving the interactivity in existing analytics techniques by means of visualization as well as interaction with intermediate results. One key method for data analysis is dimensionality reduction, for example, to produce 2D embeddings that can be visualized and analyzed efficiently. t-Distributed Stochastic Neighbor Embedding (tSNE) is a well-suited technique for the visualization of several high-dimensional data. tSNE can create meaningful intermediate results but suffers from a slow initialization that constrains its application in Progressive Visual Analytics. We introduce a controllable tSNE approximation (A-tSNE), which trades off speed and accuracy, to enable interactive data exploration. We offer real-time visualization techniques, including a density-based solution and a Magic Lens to inspect the degree of approximation. With this feedback, the user can decide on local refinements and steer the approximation level during the analysis. We demonstrate our technique with several datasets, in a real-world research scenario and for the real-time analysis of high-dimensional streams to illustrate its effectiveness for interactive data analysis. more...
- Published
- 2017
33. Efficient Stochastic Rendering of Static and Animated Volumes Using Visibility Sweeps
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Martin Eisemann, Thomas Kroes, Philipp von Radziewsky, and Elmar Eisemann
- Subjects
Computer science ,business.industry ,020207 software engineering ,Volume rendering ,02 engineering and technology ,Volumetric lighting ,Computer Graphics and Computer-Aided Design ,Real-time rendering ,3D rendering ,Rendering equation ,Rendering (computer graphics) ,Octahedron ,Image-based lighting ,Computer graphics (images) ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,Quadtree ,020201 artificial intelligence & image processing ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Alternate frame rendering ,business ,Software ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Stochastically solving the rendering integral (particularly visibility) is the de-facto standard for physically-based light transport but it is computationally expensive, especially when displaying heterogeneous volumetric data. In this work, we present efficient techniques to speed-up the rendering process via a novel visibility-estimation method in concert with an unbiased importance sampling (involving environmental lighting and visibility inside the volume), filtering, and update techniques for both static and animated scenes. Our major contributions include a progressive estimate of partial occlusions based on a fast sweeping-plane algorithm. These occlusions are stored in an octahedral representation, which can be conveniently transformed into a quadtree-based hierarchy suited for a joint importance sampling. Further, we propose sweep-space filtering, which suppresses the occurrence of fireflies and investigate different update schemes for animated scenes. Our technique is unbiased, requires little precomputation, is highly parallelizable, and is applicable to a various volume data sets, dynamic transfer functions, animated volumes and changing environmental lighting. more...
- Published
- 2017
34. Perceptual depth compression for stereo applications
- Author
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Radosław Mantiuk, Dawid Pająk, Karol Myszkowski, Kari Pulli, Robert Herzog, Piotr Didyk, and Elmar Eisemann
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Masking (art) ,Computer science ,business.industry ,media_common.quotation_subject ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Data_CODINGANDINFORMATIONTHEORY ,Computer Graphics and Computer-Aided Design ,Luminance ,Perception ,Contrast (vision) ,Codec ,Computer vision ,Artificial intelligence ,business ,Depth perception ,media_common ,Data compression - Abstract
Conventional depth video compression uses video codecs designed for color images. Given the performance of current encoding standards, this solution seems efficient. However, such an approach suffers from many issues stemming from discrepancies between depth and light perception. To exploit the inherent limitations of human depth perception, we propose a novel depth compression method that employs a disparity perception model. In contrast to previous methods, we account for disparity masking, and model a distinct relation between depth perception and contrast in luminance. Our solution is a natural extension to the H.264 codec and can easily be integrated into existing decoders. It significantly improves both the compression efficiency without sacrificing visual quality of depth of rendered content, and the output of depth-reconstruction algorithms or depth cameras. more...
- Published
- 2014
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35. Practical Real-Time Lens-Flare Rendering
- Author
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Sungkil Lee and Elmar Eisemann
- Subjects
Computer science ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Graphics hardware ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Software rendering ,Lens flare ,Image-based modeling and rendering ,Computer Graphics and Computer-Aided Design ,Ray ,Real-time rendering ,3D rendering ,Rendering (computer graphics) ,Real-time computer graphics ,Computer graphics ,Computer graphics (images) ,Ray tracing (graphics) ,Tiled rendering ,Alternate frame rendering ,business ,2D computer graphics ,3D computer graphics ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
We present a practical real-time approach for rendering lens-flare effects. While previous work employed costly ray tracing or complex polynomial expressions, we present a coarser, but also significantly faster solution. Our method is based on a first-order approximation of the ray transfer in an optical system, which allows us to derive a matrix that maps lens flare-producing light rays directly to the sensor. The resulting approach is easy to implement and produces physically-plausible images at high framerates on standard off-the-shelf graphics hardware. more...
- Published
- 2013
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36. A luminance-contrast-aware disparity model and applications
- Author
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Hans-Peter Seidel, Wojciech Matusik, Karol Myszkowski, Piotr Didyk, Elmar Eisemann, Tobias Ritschel, Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Didyk, Piotr, and Matusik, Wojciech more...
- Subjects
Computer science ,business.industry ,media_common.quotation_subject ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Stereoscopy ,Computer Graphics and Computer-Aided Design ,Luminance ,GeneralLiterature_MISCELLANEOUS ,law.invention ,law ,Perception ,Human visual system model ,Binocular disparity ,Contrast (vision) ,Computer vision ,Artificial intelligence ,Joint (audio engineering) ,Depth perception ,business ,ComputingMethodologies_COMPUTERGRAPHICS ,media_common - Abstract
Binocular disparity is one of the most important depth cues used by the human visual system. Recently developed stereo-perception models allow us to successfully manipulate disparity in order to improve viewing comfort, depth discrimination as well as stereo content compression and display. Nonetheless, all existing models neglect the substantial influence of luminance on stereo perception. Our work is the first to account for the interplay of luminance contrast (magnitude/frequency) and disparity and our model predicts the human response to complex stereo-luminance images. Besides improving existing disparity-model applications (e.g., difference metrics or compression), our approach offers new possibilities, such as joint luminance contrast and disparity manipulation or the optimization of auto-stereoscopic content. We validate our results in a user study, which also reveals the advantage of considering luminance contrast and its significant impact on disparity manipulation techniques., National Science Foundation (U.S.) (CGV-1111415) more...
- Published
- 2012
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37. Precomputed Safety Shapes for Efficient and Accurate Height-Field Rendering
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Elmar Eisemann, Lionel Baboud, and H-P Seidel
- Subjects
Height field ,business.industry ,Computer science ,Rendering algorithms ,Computer Graphics and Computer-Aided Design ,Rendering (computer graphics) ,Image synthesis ,Computer graphics ,Image texture ,Precomputation ,Signal Processing ,Computer vision ,Ray tracing (graphics) ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Shading ,business ,Texel ,Algorithm ,Software ,3D computer graphics ,ComputingMethodologies_COMPUTERGRAPHICS ,Interpolation - Abstract
Height fields have become an important element of realistic real-time image synthesis to represent surface details. In this paper, we focus on the frequent case of static height-field data, for which we can precompute acceleration structures. While many rendering algorithms exist that impose tradeoffs between speed and accuracy, we show that even accurate rendering can be combined with high performance. A careful analysis of the surface defined by the height values, leads to an efficient and accurate precomputation method. As a result, each texel stores a safety shape inside which a ray cannot cross the surface twice. This property ensures that no intersections are missed during the efficient marching method. Our analysis is general and can even consider visibility constraints that are robustly integrated into the precomputation. Further, we propose a particular instance of safety shapes with little memory overhead, which results in a rendering algorithm that outperforms existing methods, both in terms of accuracy and performance. more...
- Published
- 2012
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38. Temporal Coherence Methods in Real-Time Rendering
- Author
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Pedro V. Sander, Oliver Mattausch, Michael Wimmer, Lei Yang, Daniel Scherzer, Elmar Eisemann, and Diego Nehab
- Subjects
Global illumination ,Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,020207 software engineering ,02 engineering and technology ,Image-based modeling and rendering ,Frame rate ,Computer Graphics and Computer-Aided Design ,Real-time rendering ,Rendering (computer graphics) ,Computer engineering ,Temporal resolution ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Computer vision ,Shading ,Artificial intelligence ,Graphics ,Motion interpolation ,Alternate frame rendering ,business ,Level of detail - Abstract
Nowadays, there is a strong trend towards rendering to higher-resolution displays and at high frame rates. This development aims at delivering more detail and better accuracy, but it also comes at a significant cost. Although graphics cards continue to evolve with an ever-increasing amount of computational power, the speed gain is easily counteracted by increasingly complex and sophisticated shading computations. For real-time applications, the direct consequence is that image resolution and temporal resolution are often the first candidates to bow to the performance constraints (e.g. although full HD is possible, PS3 and XBox often render at lower resolutions). In order to achieve high-quality rendering at a lower cost, one can exploit temporal coherence (TC). The underlying observation is that a higher resolution and frame rate do not necessarily imply a much higher workload, but a larger amount of redundancy and a higher potential for amortizing rendering over several frames. In this survey, we investigate methods that make use of this principle and provide practical and theoretical advice on how to exploit TC for performance optimization. These methods not only allow incorporating more computationally intensive shading effects into many existing applications, but also offer exciting opportunities for extending high-end graphics applications to lower-spec consumer-level hardware. To this end, we first introduce the notion and main concepts of TC, including an overview of historical methods. We then describe a general approach, image-space reprojection, with several implementation algorithms that facilitate reusing shading information across adjacent frames. We also discuss data-reuse quality and performance related to reprojection techniques. Finally, in the second half of this survey, we demonstrate various applications that exploit TC in real-time rendering. © 2012 Wiley Periodicals, Inc. more...
- Published
- 2012
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39. 3D Material Style Transfer
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Karol Myszkowski, Hans-Peter Seidel, Elmar Eisemann, Tobias Ritschel, and Chuong H. Nguyen
- Subjects
Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Texture (music) ,Computer Graphics and Computer-Aided Design ,Reflectivity ,Image (mathematics) ,Style (sociolinguistics) ,Specularity ,Transfer (computing) ,Computer vision ,Artificial intelligence ,business ,Algorithm ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
This work proposes a technique to transfer the material style or mood from a guide source such as an image or video onto a target 3D scene. It formulates the problem as a combinatorial optimization of assigning discrete materials extracted from the guide source to discrete objects in the target 3D scene. The assignment is optimized to fulfill multiple goals: overall image mood based on several image statistics; spatial material organization and grouping as well as geometric similarity between objects that were assigned to similar materials. To be able to use common uncalibrated images and videos with unknown geometry and lighting as guides, a material estimation derives perceptually plausible reflectance, specularity, glossiness, and texture. Finally, results produced by our method are compared to manual material assignments in a perceptual study. © 2012 Wiley Periodicals, Inc. more...
- Published
- 2012
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40. A Computational Model of Afterimages
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Elmar Eisemann and Tobias Ritschel
- Subjects
Visual adaptation ,biology ,business.industry ,Optical illusion ,Computer science ,Graphics hardware ,OpenGL ,Retinal ,Computer Graphics and Computer-Aided Design ,Luminance ,Afterimage ,chemistry.chemical_compound ,medicine.anatomical_structure ,chemistry ,Rhodopsin ,biology.protein ,medicine ,Human eye ,Computer vision ,Artificial intelligence ,Shading ,business ,High dynamic range - Abstract
Afterimages are optical illusions, particularly well perceived when fixating an image for an extended period of time and then looking at a neutral background, where an inverted copy of the original stimulus appears. The full mechanism that produces the perceived specific colors and shapes is complex and not entirely understood, but most of the important attributes can be well explained by bleaching of retinal photoreceptors (retinal kinetics). We propose a model to compute afterimages that allows us to simulate their temporal, color and time-frequency behavior. Using this model, high dynamic range (HDR) content can be processed to add realistic afterimages to low dynamic range (LDR) media. Hereby, our approach helps in conveying the original source's luminance and contrast. It can be applied in real-time on full-HD HDR content using standard graphics hardware. Finally, our approach is validated in a perceptual study. © 2012 Wiley Periodicals, Inc. more...
- Published
- 2012
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41. Making Imperfect Shadow Maps View-Adaptive: High-Quality Global Illumination in Large Dynamic Scenes
- Author
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Hans-Peter Seidel, Elmar Eisemann, Inwoo Ha, Tobias Ritschel, and James D. K. Kim
- Subjects
Computer science ,business.industry ,Global illumination ,media_common.quotation_subject ,Visibility (geometry) ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Fidelity ,Computer Graphics and Computer-Aided Design ,Computer graphics (images) ,Point (geometry) ,Computer vision ,Imperfect ,Artificial intelligence ,Shadow mapping ,business ,Representation (mathematics) ,ComputingMethodologies_COMPUTERGRAPHICS ,media_common - Abstract
We propose an algorithm to compute interactive indirect illumination in dynamic scenes containing millions of triangles. It makes use of virtual point lights (VPL) to compute bounced illumination and a point-based scene representation to query indirect visibility, similar to Imperfect Shadow Maps (ISM). To ensure a high fidelity of indirect light and shadows, our solution is made view-adaptive by means of two orthogonal improvements: First, the VPL distribution is chosen to provide more detail, that is, more dense VPL sampling, where these contribute most to the current view. Second, the scene representation for indirect visibility is adapted to ensure geometric detail where it affects indirect shadows in the current view. more...
- Published
- 2011
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42. ManyLoDs: Parallel Many-View Level-of-Detail Selection for Real-Time Global Illumination
- Author
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Tobias Ritschel, Matthias Holländer, Elmar Eisemann, and Tamy Boubekeur
- Subjects
Pixel ,Computer science ,Global illumination ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Radiosity (computer graphics) ,Bounding volume hierarchy ,Computer Graphics and Computer-Aided Design ,Rendering (computer graphics) ,Bounding volume ,Polygon ,Computer vision ,Artificial intelligence ,business ,Level of detail ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Level-of-Detail structures are a key component for scalable rendering. Built from raw 3D data, these structures are often defined as Bounding Volume Hierarchies, providing coarse-to-fine adaptive approximations that are well-adapted for many-view rasterization. Here, the total number of pixels in each view is usually low, while the cost of choosing the appropriate LoD for each view is high. This task represents a challenge for existing GPU algorithms. We propose ManyLoDs, a new GPU algorithm to efficiently compute many LoDs from a Bounding Volume Hierarchy in parallel by balancing the workload within and among LoDs. Our approach is not specific to a particular rendering technique, can be used on lazy representations such as polygon soups, and can handle dynamic scenes. We apply our method to various many-view rasterization applications, including Instant Radiosity, Point-Based Global Illumination, and reflection / refraction mapping. For each of these, we achieve real-time performance in complex scenes at high resolutions. more...
- Published
- 2011
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43. Perceptually-motivated Real-time Temporal Upsampling of 3D Content for High-refresh-rate Displays
- Author
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Tobias Ritschel, Karol Myszkowski, Piotr Didyk, Elmar Eisemann, and Hans-Peter Seidel
- Subjects
Liquid-crystal display ,Computer science ,business.industry ,Graphics hardware ,Optical flow ,Computer Graphics and Computer-Aided Design ,law.invention ,Refresh rate ,Upsampling ,Task (computing) ,law ,Temporal resolution ,Computer vision ,Artificial intelligence ,business - Abstract
High-refresh-rate displays (e. g., 120 Hz) have recently become available on the consumer market and quickly gain on popularity. One of their aims is to reduce the perceived blur created by moving objects that are tracked by the human eye. However, an improvement is only achieved if the video stream is produced at the same high refresh rate (i. e. 120 Hz). Some devices, such as LCD TVs, solve this problem by converting low-refresh-rate content (i. e. 50 Hz PAL) into a higher temporal resolution (i. e. 200 Hz) based on two-dimensional optical flow. In our approach, we will show how rendered three-dimensional images produced by recent graphics hardware can be up-sampled more efficiently resulting in higher quality at the same time. Our algorithm relies on several perceptual findings and preserves the naturalness of the original sequence. A psychophysical study validates our approach and illustrates that temporally up-sampled video streams are preferred over the standard low-rate input by the majority of users. We show that our solution improves task performance on high-refresh-rate displays. more...
- Published
- 2010
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44. Depth-of-field rendering with multiview synthesis
- Author
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Sungkil Lee, Hans-Peter Seidel, and Elmar Eisemann
- Subjects
business.industry ,Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Image-based modeling and rendering ,Computer Graphics and Computer-Aided Design ,3D rendering ,Rendering (computer graphics) ,Computer graphics (images) ,Computer vision ,Artificial intelligence ,Shading ,Depth of field ,Cone tracing ,Tiled rendering ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
We present a GPU-based real-time rendering method that simulates high-quality depth-of-field effects, similar in quality to multiview accumulation methods. Most real-time approaches have difficulties to obtain good approximations of visibility and view-dependent shading due to the use of a single view image. Our method also avoids the multiple rendering of a scene, but can approximate different views by relying on a layered image-based scene representation. We present several performance and quality improvements, such as early culling, approximate cone tracing, and jittered sampling. Our method achieves artifact-free results for complex scenes and reasonable depth-of-field blur in real time. more...
- Published
- 2009
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45. Clip Art Rendering of Smooth Isosurfaces
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Elmar Eisemann, Matei Stroila, John Hart, University of Illinois at Urbana-Champaign [Urbana], University of Illinois System, Acquisition, representation and transformations for image synthesis (ARTIS), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), University of Illinois at Urbana Champaign (UIUC), and University of Illinois System-University of Illinois System more...
- Subjects
Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Clip art ,02 engineering and technology ,non-photorealistic rendering ,050105 experimental psychology ,Pattern Recognition, Automated ,Silhouette ,Rendering (computer graphics) ,Computer graphics ,User-Computer Interface ,Vector graphics ,Imaging, Three-Dimensional ,Computer graphics (images) ,Image Interpretation, Computer-Assisted ,Shadow ,Computer Graphics ,0202 electrical engineering, electronic engineering, information engineering ,0501 psychology and cognitive sciences ,Computer vision ,particle systems ,ComputingMethodologies_COMPUTERGRAPHICS ,Particle system ,business.industry ,line art drawing ,05 social sciences ,020207 software engineering ,Image Enhancement ,Computer Graphics and Computer-Aided Design ,[INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR] ,Non-photorealistic rendering ,Signal Processing ,Polygon ,Computer Vision and Pattern Recognition ,Artificial intelligence ,business ,Algorithms ,Software - Abstract
International audience; Clip art is a simplified illustration form consisting of layered filled polygons or closed curves used to convey 3-D shape information in a 2-D vector graphics format. This paper focuses on the problem of direct conversion of smooth surfaces, ranging from the free-form shapes of art and design to the mathematical structures of geometry and topology, into a clip art form suitable for illustration use in books, papers and presentations. We show how to represent silhouette, shadow, gleam and other surface feature curves as the intersection of implicit surfaces, and derive equations for their efficient interrogation via particle chains. We further describe how to sort, orient, identify and fill the closed regions that overlay to form clip art. We demonstrate the results with numerous renderings used to illustrate the paper itself. More at http://artis.imag.fr/Publications/2008/SEH08/ more...
- Published
- 2008
- Full Text
- View/download PDF
46. An Affordable Solution for Binocular Eye Tracking and Calibration in Head-mounted Displays
- Author
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Martin Eisemann, Steve Grogorick, Michael Stengel, Elmar Eisemann, and Marcus Magnor
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Monocular ,Eye tracking system ,Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Optical head-mounted display ,Virtual reality ,medicine.disease ,Gaze ,Rendering (computer graphics) ,InformationSystems_MODELSANDPRINCIPLES ,Motion sickness ,Computer graphics (images) ,medicine ,Immersion (virtual reality) ,Eye tracking ,Computer vision ,Depth of field ,Artificial intelligence ,business - Abstract
Immersion is the ultimate goal of head-mounted displays (HMD) for Virtual Reality (VR) in order to produce a convincing user experience. Two important aspects in this context are motion sickness, often due to imprecise calibration, and the integration of a reliable eye tracking. We propose an affordable hard- and software solution for drift-free eye-tracking and user-friendly lens calibration within an HMD. The use of dichroic mirrors leads to a lean design that provides the full field-of-view (FOV) while using commodity cameras for eye tracking. Our prototype supports personalizable lens positioning to accommodate for different interocular distances. On the software side, a model-based calibration procedure adjusts the eye tracking system and gaze estimation to varying lens positions. Challenges such as partial occlusions due to the lens holders and eye lids are handled by a novel robust monocular pupil-tracking approach. We present four applications of our work: Gaze map estimation, foveated rendering for depth of field, gaze-contingent level-of-detail, and gaze control of virtual avatars. more...
- Published
- 2015
- Full Text
- View/download PDF
47. Adaptively layered statistical volumetric obscurance
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Leonardo Scandolo, Martin Eisemann, Elmar Eisemann, and Quintjin Hendrickx
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Global illumination ,business.industry ,Computer science ,Graphics hardware ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Statistical model ,Computer graphics ,Undersampling ,Tangent space ,Ambient occlusion ,Computer vision ,Noise (video) ,Artificial intelligence ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
We accelerate volumetric obscurance, a variant of ambient occlusion, and solve undersampling artifacts, such as banding, noise or blurring, that screen-space techniques traditionally suffer from. We make use of an efficient statistical model to evaluate the occlusion factor in screen-space using a single sample. Overestimations and halos are reduced by an adaptive layering of the visible geometry. Bias at tilted surfaces is avoided by projecting and evaluating the volumetric obscurance in tangent space of each surface point. We compare our approach to several traditional screen-space ambient obscurance techniques and show its competitive qualitative and quantitative performance. Our algorithm maps well to graphics hardware, does not require the traditional bilateral blur step of previous approaches, and avoids typical screen-space related artifacts such as temporal instability due to undersampling. more...
- Published
- 2015
- Full Text
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48. Non-obscuring binocular eye tracking for wide field-of-view head-mounted-displays
- Author
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Steve Grogorick, Martin Eisemann, Marcus Magnor, Elmar Eisemann, and Michael Stengel
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Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Virtual reality ,Tracking (particle physics) ,Gaze ,Pupil ,law.invention ,Real-time computer graphics ,Lens (optics) ,InformationSystems_MODELSANDPRINCIPLES ,law ,Computer graphics (images) ,Eye tracking ,Computer vision ,Artificial intelligence ,business ,3D computer graphics - Abstract
We present a complete hardware and software solution for integrating binocular eye tracking into current state-of-the-art lens-based Head-mounted Displays (HMDs) without affecting the user's wide field-of-view off the display. The system uses robust and efficient new algorithms for calibration and pupil tracking and allows realtime eye tracking and gaze estimation. Estimating the relative gaze direction of the user opens the door to a much wider spectrum of virtual reality applications and games when using HMDs. We show a 3d-printed prototype of a low-cost HMD with eye tracking that is simple to fabricate and discuss a variety of VR applications utilizing gaze estimation. more...
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- 2015
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49. ChromoStereoscopic rendering for trichromatic displays
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Leila Schemali, Elmar Eisemann, Laboratoire Traitement et Communication de l'Information (LTCI), Télécom ParisTech-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Computer Graphics and Visualization, Delft University of Technology (TU Delft), and ACM more...
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Chromostereopsis ,business.industry ,Computer science ,Trichromacy ,Stereoscopy ,[INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR] ,law.invention ,Rendering (computer graphics) ,law ,I.3.3 [Computer Graphics]: Three-Dimensional Graphics and Realism--Display Algorithms ,Chromatic aberration ,Human visual system model ,Computer vision ,display algorithms ,Artificial intelligence ,business ,Depth perception ,chromostereoscopy ,Hue ,stereoscopic rendering - Abstract
International audience; The chromostereopsis phenomenom leads to a differing depth perception of different color hues, e.g., red is perceived slightly in front of blue. In chromostereoscopic rendering 2D images are produced that encode depth in color. While the natural chromostereopsis of our human visual system is rather low, it can be enhanced via ChromaDepth®glasses, which induce chromatic aberrations in one eye by refracting light of different wavelengths differently, hereby offsetting the projected position slightly in one eye. Although, it might seem natural to map depth linearly to hue, which was also the basis of previous solutions, we demonstrate that such a mapping reduces the stereoscopic effect when using standard trichromatic displays or printing systems. We propose an algorithm, which enables an improved stereoscopic experience with reduced artifacts. more...
- Published
- 2014
- Full Text
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50. Prefiltered single scattering
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Oliver Klehm, Elmar Eisemann, and Hans-Peter Seidel
- Subjects
Scattering ,business.industry ,Computer science ,OpenGL ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Process (computing) ,Display resolution ,Light scattering ,Rectification ,Texture filtering ,Computer vision ,Artificial intelligence ,Shadow mapping ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Volumetric light scattering is a complex phenomenon that is difficult to simulate in real time as light can be scattered towards the camera from everywhere in space. By assuming a single-scattering model, we can transform the usually-employed ray-marching into an efficient ray-independent texture filtering process. Our algorithm builds upon a rectified shadow map as input and we propose an efficient rectification scheme, which could be used by other approaches as well. The resulting scattering method is very fast and almost independent of the screen resolution, but it still produces near-reference results. These properties make it a good candidate for performance-critical applications, such as games. more...
- Published
- 2014
- Full Text
- View/download PDF
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