We present an interactive navigation system for virtual colonoscopy, which is based solely on high performance volume rendering. Previous colonic navigation systems have employed either a surface rendering or a Z-buff...
ISBN:
(纸本)9780780358973
We present an interactive navigation system for virtual colonoscopy, which is based solely on high performance volume rendering. Previous colonic navigation systems have employed either a surface rendering or a Z-buffer-assisted volume rendering method that depends on the surface rendering results. Our method is a fast direct volume rendering technique that exploits distance information stored in the potential field of the camera control model, and is parallelized on a multiprocessor. Experiments have been conducted on both a simulated pipe and patients' data sets acquired with a CT scanner.
We augment schematic maps of transportation systems by superimposing them on street-level maps that are fitted using image warping techniques. While schematic maps are successful in conveying information about lines a...
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ISBN:
(纸本)9781424419661
We augment schematic maps of transportation systems by superimposing them on street-level maps that are fitted using image warping techniques. While schematic maps are successful in conveying information about lines and connections in a public transportation network, they usually contain little or no detail describing the environment of stations or their embedding in the surrounding area. The annotation of a distorted city map therefore alleviates this deficiency and improves further the usability of schematic transportation maps by merging two different navigational spaces. Our technique for fitting the street map to the schematic map is based on moving least squares in combination with an overlap control technique. We thus obtain an easily readable transportation network map on which we can show all the typical city map features such as rivers, streets, and parks without compromising on the schematization. Furthermore, for the interactive exploration we couple zooming with warping and control over the level of detail in what we call Warping Zoom.
Videographers have developed an art of conveying events in video. Through choices made in cinematography, editing, and post-processing, effective video presentations can be created from events recorded with little or ...
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ISBN:
(纸本)9781581131987
Videographers have developed an art of conveying events in video. Through choices made in cinematography, editing, and post-processing, effective video presentations can be created from events recorded with little or no intrusion. In this paper, we explore systems that bring videography to situations where cost or time issues preclude application of the art. Our goal is to develop virtual videography, that is, systems that can help automate the process of creating an effective video presentation from given footage. In this paper, we discuss how virtual videography systems can be constructed by combining image-based rendering to synthetically generate shots with image understanding to help choose what should be shown to the viewer. To this, visual effects can be added to enhance the presentation, lessening the degradation caused by the medium.
The MAMView framework is a data exploration tool that allows developers and users of Metric Access Methods (MAMs) to explore and share dynamic and interactive 3D presentations of a MAM, making the understanding of tho...
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ISBN:
(纸本)9781581139648
The MAMView framework is a data exploration tool that allows developers and users of Metric Access Methods (MAMs) to explore and share dynamic and interactive 3D presentations of a MAM, making the understanding of those structures easier. It is able to create visual representations of metric datasets, including high-dimensional and non-dimensional information. This is achieved by using an extension of the FastMap algorithm. This framework was developed as a practical tool that has been successfully applied to study existing MAMs, helping both new and experienced users to better understand them. The MAMView was also applied to a new under development MAM. With MAMView in hands, the development team of this MAM was able to drill-down its algorithms, quickly finding problems and also potential points for improvement and optimizations. Our focus on this work is on proposing an intuitive yet powerful visualization framework that can be easily employed to build intuitive visual presentations that can bypass the drawback of MAMs dealing with datasets with no spatial representation. Besides MAMView being a powerful visualization tool, its greatest strengths are the ability to interactively explore a visual presentation of a MAM at any level of detail, and the ability to seamlessly query and produce graphical representations in XML format that can be straightforward executed. This paper presents the MAMView framework and its main techniques, describes the current tool, and reports on our experiences in applying it to real applications. Copyright 2005 acm.
作者：
Valle, GiorgioFacoltà di Ingegneria
Istituto di Elettronica Viale Risorgimento 2 Bologna40136 Italy CNR
Centro di Studio per l'Interazione Operatore - Calcolatore Italy
The organization of the data structure has traditionally been a key element in the design of successful interactive systems, either aiming at specific technical applications as the ones related to computer aided desig...
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General sparse matrix-matrix multiplication (SpGEMM) is a core component of many algorithms. A number of recent works have used high throughput graphics processing units (GPUs) to accelerate SpGEMM. However, exploitin...
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The paper presents interactive flow visualization methods that highlight directional information in the flow field. An added benefit of the proposed methods is that they reduce the amount of data being displayed and h...
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ISBN:
(纸本)9780897918640
The paper presents interactive flow visualization methods that highlight directional information in the flow field. An added benefit of the proposed methods is that they reduce the amount of data being displayed and hence reduce clutter. The main idea behind these methods is the use of light sources to select and highlight regions in the flow field with similar directions. Varying the lighting conditions, by moving the light source and/or adding more lights, emphasizes different vector directions, set of directions, and vectors within a specified angle of a particular direction. The methods are straight forward, computationally inexpensive, and can be combined with other techniques that use glyph representation and other flow geometry such as streamlines for feature visualization. The authors apply these methods to an analytic data set to help explain how they work, and then to a simulation data set to highlight flow reversals.
This paper presents a new method for interactive rendering of globally illuminated static scenes. Global illumination is decomposed into view-independent (diffuse) and view-dependent (non-diffuse) components. The two ...
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This paper presents a new method for interactive rendering of globally illuminated static scenes. Global illumination is decomposed into view-independent (diffuse) and view-dependent (non-diffuse) components. The two are recombined during rendering using a hybrid geometry- and image-based approach along with multi-pass blending techniques. This approach allows the preprocessing of both components and the fast rendering of globally illuminated scenes. The view-independent component uses a traditional precomputed geometry-based radiosity solution that is rendered using standard graphics hardware. The view-dependent component is decomposed into `what is reflected' (radiance with depth) and `how it is reflected' (BRDF), and precomputed and rendered using image-based approaches. Radiance is stored as images with depth, and rendered using perspective reprojection;the BRDF is decomposed into an integration of incoming radiance and a directional modulation. The radiance integration term is approximated by convolving the reflected image with precomputed kernel textures based on material properties. The directional modulation is stored as a reflectance modulation texture based on material properties and is rendered using sphere-mapping during a blending pass.
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