bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Design of an Inexpensive Very High Resolution Scan Camera System
Authors: Wang Shuzhen , Heidrich Wolfgang 
Published: August 2004

Abstract We describe a system for transforming an off‐the‐shelf flatbed scanner into a $200 scan backend for large format cameras. While we describe both software and hardware aspects, the focus of the paper is on software issues such as color calibration and removal of scanner artifacts. With current scanner technology, the resulting camera system is capable of taking black&white, color, or near‐infrared photographs with up to 490 million pixels. Our analysis shows that we achieve actual optical resolutions close to the theoretical maximum, and that color reproduction is comparable to commercial camera systems. We believe that the camera system described here has many potential applications in image‐based modeling and rendering, cultural heritage projects, and professional digital photography.
Quadric Transfer for Immersive Curved Screen Displays
Authors: Raskar Ramesh , van Baar Jeroen , Willwacher Thomas , Rao Srinivas 
Published: August 2004

Abstract Curved screens are increasingly being used for high‐resolution immersive visualization environments. We describe a new technique to display seamless images using overlapping projectors on curved quadric surfaces such as spherical or cylindrical shape. We exploit a quadric image transfer function and show how it can be used to achieve sub‐pixel registration while interactively displaying two or three‐dimensional datasets for a head‐tracked user. Current techniques for automatically registered seamless displays have focused mainly on planar displays. On the other hand, techniques for curved screens currently involve cumbersome manual alignment to make the installation conform to the intended design. We show a seamless real‐time display system and discuss our methods for smooth intensity blending and efficient rendering. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism‐ Virtual reality
Topological Construction and Visualization of Higher Order 3D Vector Fields
Authors: Weinkauf Tino , Theisel Holger , Hege Hans‐Christian , Seidel Hans‐Peter 
Published: August 2004

Abstract We present the first algorithm for constructing 3D vector fields based on their topological skeleton. The skeleton itself is modeled by interactively moving a number of control polygons. Then a piecewise linear vector field is automatically constructed which has the same topological skeleton as modeled before. This approach is based on a complete segmentation of the areas around critical points into sectors of different flow behavior. Based on this, we present the first approach to visualizing higher order critical points of 3D vector fields. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Line and Curve Generation I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism
Dye Advection Without the Blur: A Level‐Set Approach for Texture‐Based Visualization of Unsteady Flow
Authors: Weiskopf D. 
Published: August 2004

Abstract Dye advection is an intuitive and versatile technique to visualize both steady and unsteady flow. Dye can be easily combined with noise‐based dense vector field representations and is an important element in user‐centric visual exploration processes. However, fast texture‐based implementations of dye advection rely on linear interpolation operations that lead to severe diffusion artifacts. In this paper, a novel approach for dye advection is proposed to avoid this blurring and to achieve long and clearly defined streaklines or extended streak‐like patterns. The interface between dye and background is modeled as a level‐set within a signed distance field. The level‐set evolution is governed by the underlying flow field and is computed by a semi‐Lagrangian method. A reinitialization technique is used to counteract the distortions introduced by the level‐set evolution and to maintain a level‐set function that represents a local distance field. This approach works for 2D and 3D flow fields alike. It is demonstrated how the texture‐based level‐set representation lends itself to an efficient GPU implementation and therefore facilitates interactive visualization. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Picture/Image Generation I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism
Instant Volumetric Understanding with Order‐Independent Volume Rendering
Authors: Mora Benjamin , Evert David S. 
Published: August 2004

Abstract Rapid, visual understanding of volumetric datasets is a crucial outcome of a good volume rendering application, but few current volume rendering systems deliver this result. Our goal is to reduce the volumetric surfing that is required to understand volumetric features by conveying more information in fewer images. In order to achieve this goal, and in contrast with most current methods which still use optical models and alpha blending, our approach reintroduces the order‐independent contribution of every sample along the ray in order to have an equiprobable visualization of all the volume samples. Therefore, we demonstrate how order independent sampling can be suitable for fast volume understanding, show useful extensions to MIP and X‐ray like renderings, and, finally, point out the special advantage of using stereo visualization in these models to circumvent the lack of depth cues. Categories and Subject Descriptors: I.3.3 [Computer Graphics]: Picture/Image, Generation, I.3.7 [Computer Graphics]: Three‐Dimensional graphics and realism.
Way‐Finder: guided tours through complex walkthrough models
Authors: Andújar C. , Vázquez P. , Fairén M. 
Published: August 2004

Abstract The exploration of complex walkthrough models is often a difficult task due to the presence of densely occluded regions which pose a serious challenge to online navigation. In this paper we address the problem of algorithmic generation of exploration paths for complex walkthrough models. We present a characterization of suitable properties for camera paths and we discuss an efficient algorithm for computing them with little or no user intervention. Our approach is based on identifying the free‐space structure of the scene (represented by a cell and portal graph) and an entropy‐based measure of the relevance of a view‐point. This metric is key for deciding which cells have to be visited and for computing critical way‐points inside each cell. Several results on different model categories are presented and discussed.
Crowd of Virtual Humans: a New Approach for Real Time Navigation in Complex and Structured Environments
Authors: Lamarche Fabrice , Donikian Stéphane 
Published: August 2004

Abstract The navigation activity is an every day practice for any human being capable of locomotion. Our objective in this work is to reproduce this crucial human activity inside virtual environments. Putting together the high complexity of a realistic environment such as a city, a big amount of virtual humans and the real‐time constraint requires to optimize each aspect of the animation process. In this paper, we present a suitable topological structuring of the geometric environment to allow fast path finding as well as an efficient reactive navigation algorithm for virtual humans evolving inside a crowd.
Scalable behaviors for crowd simulation
Authors: Sung Mankyu , Gleicher Michael , Chenney Stephen 
Published: August 2004

Abstract Crowd simulation for virtual environments offers many challenges centered on the trade‐offs between rich behavior, control and computational cost. In this paper we present a new approach to controlling the behavior of agents in a crowd. Our method is scalable in the sense that increasingly complex crowd behaviors can be created without a corresponding increase in the complexity of the agents. Our approach is also more authorable; users can dynamically specify which crowd behaviors happen in various parts of an environment. Finally, the character motion produced by our system is visually convincing. We achieve our aims with a situation‐based control structure. Basic agents have very limited behaviors. As they enter new situations, additional, situation‐specific behaviors are composed on the fly to enable agents to respond appropriately. The composition is done using a probabilistic mechanism. We demonstrate our system with three environments including a city street and a theater.Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Animation
Real‐time Rigid Body Simulation for Haptic Interactions Based on Contact Volume of Polygonal Objects
Authors: Hasegawa S. , Sato M. 
Published: August 2004

Abstract This paper proposes a new method for real‐time rigid body simulations for haptic interactions based on a penalty method regarding contact volume. Analytical methods for calculation of contact forces require too much time to maintain fast update rates for haptic controls. In addition, they prohibit direct connection of haptic interfaces. Penalty methods, which employ spring‐damper models for calculation of contact forces, offer a very rapid rate of iterations. In addition, they permit direct connection of haptic interfaces. Penalty methods are good for haptic interactions. However, previous penalty methods do not regard distribution of contact forces over the contact area. For that reason, they can't calculate normal and friction forces on face‐face contacts correctly. We propose a distributed spring‐damper model on a contact area to solve these problems. We analyze three‐dimensional geometries of the intersecting portion on the polyhedral objects. Then, we integrate forces and torques of distributed spring‐damper models. We implement a proposed simulator and compare it with a point‐based penalty method and constraint method. The comparison shows that the proposed simulator improves accuracy of the simulation of face‐face contact and friction forces and the simulation speed. In addition, we attach a six degree‐of‐freedom (6‐DOF) haptic interface to the simulator. Users can feel 6‐DOF force feedback and input 6‐DOF motions. Categories and Subject Descriptors (according to ACM CCS): I.6.5 [Model Development]: Modeling methodologies, H.5.2 [User Interfaces]: Haptic I/O, I.3.6 [Methodology and Techniques]: Interaction techniques
Synthesizing Sound from Turbulent Field using Sound Textures for Interactive Fluid Simulation
Authors: Dobashi Yoshinori , Yamamoto Tsuyoshi , Nishita Tomoyuki 
Published: August 2004

Abstract Sound is an indispensable element for the simulation of a realistic virtual environment. Therefore, there has been much recent research focused on the simulation of realistic sound effects. This paper proposes a method for creating sound for turbulent phenomena such as fire. In a turbulent field, the complex motion of vortices leads to the generation of sound. This type of sound is called a vortex sound. The proposed method simulates a vortex sound by computing vorticity distributions using computational fluid dynamics. Sound textures for the vortex sound are first created in a pre‐process step. The sound is then created at interactive rates by using these sound textures. The usefulness of the proposed method is demonstrated by applying it to the simulation of the sound of fire and other turbulent phenomena. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism ‐ Animation; I.6.8 [Simulation and Modeling]: Types of Simulation ‐ Animation; I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism; I.6.3 [Simulation and Modeling]: Applications; H.5.5 [Information Interfaces and Presentation]: Sound and Music Computing ‐ Methodologies and techniques, Modeling.
DiFi: Fast 3D Distance Field Computation Using Graphics Hardware
Authors: Sud Avneesh , Otaduy Miguel A. , Manocha Dinesh 
Published: August 2004

Abstract We present an algorithm for fast computation of discretized 3D distance fields using graphics hardware. Given a set of primitives and a distance metric, our algorithm computes the distance field for each slice of a uniform spatial grid baly rasterizing the distance functions of the primitives. We compute bounds on the spatial extent of the Voronoi region of each primitive. These bounds are used to cull and clamp the distance functions rendered for each slice. Our algorithm is applicable to all geometric models and does not make any assumptions about connectivity or a manifold representation. We have used our algorithm to compute distance fields of large models composed of tens of thousands of primitives on high resolution grids. Moreover, we demonstrate its application to medial axis evaluation and proximity computations. As compared to earlier approaches, we are able to achieve an order of magnitude improvement in the running time. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Distance fields, Voronoi regions, graphics hardware, proximity computations
Point Cloud Collision Detection
Authors: Klein Jan , Zachmann Gabriel 
Published: August 2004

AbstractIn the past few years, many efficient rendering and surface reconstruction algorithms for point clouds have been developed. However, collision detection of point clouds has not been considered until now, although this is a prerequisite to use them for interactive or animated 3D graphics.We present a novel approach for time‐critical collision detection of point clouds. Based solely on the point representation, it can detect intersections of the underlying implicit surfaces. The surfaces do not need to be closed.We construct a point hierarchy where each node stores a sufficient sample of the points plus a sphere covering of a part of the surface. These are used to derive criteria that guide our hierarchy traversal so as to increase convergence. One of them can be used to prune pairs of nodes, the other one is used to prioritize still to be visited pairs of nodes. At the leaves we efficiently determine an intersection by estimating the smallest distance.We have tested our implementation for several large point cloud models. The results show that a very fast and precise answer to collision detection queries can always be given.Categories and Subject Descriptors (according to ACM CCS): G.1.2 [Numerical Analysis]: Approximation of surfaces and contours I.3.5 [Computer Graphics]: Computational Geometry and Object‐Modeling[Geometric algorithms, languages and systems; object hierarchy; physically‐based modeling] I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism[Animation; virtual reality]
A Progressive Rendering Algorithm Using an Adaptive Perceptually Based Image Metric
Authors: Farrugia Jean‐Philippe , Péroche Bernard 
Published: August 2004

Abstract In this paper, we propose to solve the global illumination problem through a progressive rendering method relying on an adaptive sampling of the image space. The refinement of this sample scheme is driven by an image metric based on a powerful vision model. A Delaunay triangulation of the sampled points is followed by a classification of these triangles into three classes. By interpolating each triangle according to the class it belongs to, we can obtain a high quality image by computing only a fraction of all the pixels and thus saving computation time. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Perceptual Rendering, Global illumination
Coherent Hierarchical Culling: Hardware Occlusion Queries Made Useful
Authors: Bittner Jiří , Wimmer Michael , Piringer Harald , Purgathofer Werner 
Published: August 2004

Abstract We present a simple but powerful algorithm for optimizing the usage of hardware occlusion queries in arbitrary complex scenes. Our method minimizes the number of issued queries and reduces the delays due to the latency of query results. We reuse the results of occlusion queries from the last frame in order to initiate and schedule the queries in the next frame. This is done by processing nodes of a spatial hierarchy in a front‐to‐back order and interleaving occlusion queries with rendering of certain previously visible nodes. The proposed scheduling of the queries makes use of spatial and temporal coherence of visibility. Despite its simplicity, the algorithm achieves good culling efficiency for scenes of various types. The implementation of the algorithm is straightforward and it can be easily integrated in existing real‐time rendering packages based on common hierarchical data structures. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism
Hardware‐Accelerated Rendering of Photo Hulls
Authors: Li Ming , Magnor Marcus , Seidel Hans‐Peter 
Published: August 2004

Abstract This paper presents an efficient hardware‐accelerated method for novel view synthesis from a set of images or videos. Our method is based on the photo hull representation, which is the maximal photo‐consistent shape. We avoid the explicit reconstruction of photo hulls by adopting a view‐dependent plane‐sweeping strategy. From the target viewpoint slicing planes are rendered with reference views projected onto them. Graphics hardware is exploited to verify the photo‐consistency of each rasterized fragment. Visibilities with respect to reference views are properly modeled, and only photo‐consistent fragments are kept and colored in the target view. We present experiments with real images and animation sequences. Thanks to the more accurate shape of the photo hull representation, our method generates more realistic rendering results than methods based on visual hulls. Currently, we achieve rendering frame rates of 2–3 fps. Compared to a pure software implementation, the performance of our hardware‐accelerated method is approximately 7 times faster.Categories and Subject Descriptors (according to ACM CCS): CR Categories: I.3.3 [Computer Graphics]: Picture/Image Generation; I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism.
Optimized Sub‐Sampling of Point Sets for Surface Splatting
Authors: Wu Jainhua , Kobbelt Leif 
Published: August 2004

Abstract Using surface splats as a rendering primitive has gained increasing attention recently due to its potential for high‐performance and high‐quality rendering of complex geometric models. However, as with any other rendering primitive, the processing costs are still proportional to the number of primitives that we use to represent a given object. This is why complexity reduction for point‐sampled geometry is as important as it is, e.g., for triangle meshes. In this paper we present a new sub‐sampling technique for dense point clouds which is specifically adjusted to the particular geometric properties of circular or elliptical surface splats. A global optimization scheme computes an approximately minimal set of splats that covers the entire surface while staying below a globally prescribed maximum error toleranceε. Since our algorithm converts pure point sample data into surface splats with normal vectors and spatial extent, it can also be considered as a surface reconstruction technique which generates a hole‐free piecewise linearC−1continuous approximation of the input data. Here we can exploit the higher flexibility of surface splats compared to triangle meshes. Compared to previous work in this area we are able to obtain significantly lower splat numbers for a given error tolerance.
Deferred Splatting
Authors: Guennebaud Gaël , Barthe Loïc , Paulin Mathias 
Published: August 2004

Abstract In recent years it has been shown that, above a certain complexity, points become the most efficient rendering primitives. Although the programmability of the lastest graphics hardware allows efficient implementation of high quality surface splatting algorithms, their performance remains below those obtained with simpler point based rendering algorithms when they are used for scenes of high complexity. In this paper, our goal is to apply high quality point based rendering algorithms on complex scenes. For this purpose, we show how to take advantage of temporal coherency in a very accurate hardware accelerated point selection algorithm allowing the expensive computations to be peformed only on visible points. Our algorithm is based on a multi‐pass hardware accelerated EWA splatting. It is also suitable for any rendering application since no pre‐process is needed and no assumption is made on the data structure. In addition, we briefly discuss the association of our method with other existing culling techniques and optimization for particular applications. Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Viewing algorithms
Exchanging Faces in Images
Authors: Blanz Volker , Scherbaum Kristina , Vetter Thomas , Seidel Hans‐Peter 
Published: August 2004

Abstract Pasting somebody's face into an existing image with traditional photo retouching and digital image processing tools has only been possible if both images show the face from the same viewpoint and with the same illumination. However, this is rarely the case for given pairs of images. We present a system that exchanges faces across large differences in viewpoint and illumination. It is based on an algorithm that estimates 3D shape and texture along with all relevant scene parameters, such as pose and lighting, from single images. Manual interaction is reduced to clicking on a set of about 7 feature points, and marking the hairline in the target image. The system can be used for image processing, virtual try‐on of hairstyles, and face recognition. By separating face identity from imaging conditions, our approach provides an abstract representation of images and a novel, high‐level tool for image manipulation. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Animation
High Resolution Acquisition, Learning and Transfer of Dynamic 3‐D Facial Expressions
Authors: Wang Yang , Huang Xiaolei , Lee Chan‐Su , Zhang Song , Li Zhiguo , Samaras Dimitris , Metaxas Dimitris , Elgammal Ahmed , Huang Peisen 
Published: August 2004

Abstract Synthesis and re‐targeting of facial expressions is central to facial animation and often involves significant manual work in order to achieve realistic expressions, due to the difficulty of capturing high quality dynamic expression data. In this paper we address fundamental issues regarding the use of high quality dense 3‐D data samples undergoing motions at video speeds, e.g. human facial expressions. In order to utilize such data for motion analysis and re‐targeting, correspondences must be established between data in different frames of the same faces as well as between different faces. We present a data driven approach that consists of four parts: 1) High speed, high accuracy capture of moving faces without the use of markers, 2) Very precise tracking of facial motion using a multi‐resolution deformable mesh, 3) A unified low dimensional mapping of dynamic facial motion that can separate expression style, and 4) Synthesis of novel expressions as a combination of expression styles. The accuracy and resolution of our method allows us to capture and track subtle expression details. The low dimensional representation of motion data in a unified embedding for all the subjects in the database allows for learning the most discriminating characteristics of each individual's expressions as that person's “expression style”. Thus new expressions can be synthesized, either as dynamic morphing between individuals, or as expression transfer from a source face to a target face, as demonstrated in a series of experiments. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Animation; I.3.5 [Computer Graphics]: Curve, surface, solid, and object representations; I.3.3 [Computer Graphics]: Digitizing and scanning; I.2.10 [Artificial intelligence]: Motion ; I.2.10 [Artificial intelligence]: Representations, data structures, and transforms; I.2.10 [Artificial intelligence]: Shape; I.2.6 [Artificial intelligence]: Concept learning