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Visualization and Computer Graphics, IEEE Transactions on

Issue 1 • Date Mar 1995

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Displaying Results 1 - 6 of 6
  • Optimal sampling for hemicubes

    Publication Year: 1995 , Page(s): 60 - 76
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1204 KB)  

    The hemicube estimates of form factors are based on a finite set of sample directions. We obtain several optimal arrangements of sample directions, which minimize the variance of these estimates. They are based on changing the size or shape of the pixels or the shape of the hemicube, or using non-uniform pixel grids. The best reduces the variance by 43%. The variance calculation is based on the assumption that the errors in the estimate are caused by the projections of single polygon edges, and that the positions and orientations of these edges are random. This replaces the infinite dimensional space of possible environments by the two dimensional space of great circles on the unit sphere, making the numerical variance minimization possible View full abstract»

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  • Volume rendering of DCT-based compressed 3D scalar data

    Publication Year: 1995 , Page(s): 29 - 43
    Cited by:  Papers (37)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1184 KB)  

    The paper proposes a scheme to perform volume rendering from compressed scalar data. Instead of decompressing the entire data set before rendering, blocks of data are decompressed as needed. Discrete cosine transform based compression technique is used to illustrate the method. The data is partitioned into overlapping blocks to permit local rendering and allow easy parallelization. Compression by factor of 20 to 30 produces rendering virtually indistinguishable from rendering using the original uncompressed data. Speedup is obtained by making use of spatial homogeneity detected in the transform domain. Rendering time using the proposed approach is less than that of direct rendering from the entire uncompressed data. The proposed method thus offers an attractive option to reduce storage, computation, and transmission overhead of otherwise huge data sets View full abstract»

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  • Visualization of multidimensional shape and texture features in laser range data using complex-valued Gabor wavelets

    Publication Year: 1995 , Page(s): 44 - 59
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1332 KB)  

    The paper describes a new method for visualization and analysis of multivariate laser range data using complex valued non orthogonal Gabor wavelets (D. Gabor, 1946), principal component analysis and a topological mapping network. The initial data set that provides both shape and texture information is encoded in terms of both amplitude and phase of a complex valued 2D image function. A set of carefully designed oriented Gabor filters performs a decomposition of the data and allows for retrieving local shape and texture features. The feature vector obtained from this method is multidimensional and in order to evaluate similar data features, further subspace methods to transform the data onto visualizable attributes, such as R, G, B, have to be determined. For this purpose, a feature based visualization pipeline is proposed consisting of principal component analysis, normalization and a topological mapping network. This process finally renders a R,G,B subspace representation of the multidimensional feature vector. Our method is primarily applied to the visual analysis of features in human faces but is not restricted to that View full abstract»

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  • Vision-an architecture for global illumination calculations

    Publication Year: 1995 , Page(s): 77 - 96
    Cited by:  Papers (3)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1920 KB)  

    So far, the problem of global illumination calculation has almost exclusively been approached from an algorithmic point of view. We propose an architectural approach to global illumination. The proposed rendering architecture Vision is derived from a model of the physical rendering process, which is subsequently mapped onto an object-oriented hierarchy of classes. This design is powerful and flexible enough to support and exploit a large body of existing illumination algorithms for the simulation of various aspects of the underlying physical model. Additionally, the Vision architecture offers a platform for developing new algorithms and for combining them to create new rendering solutions. We discuss both abstract design as well as implementation issues. In particular, we give a detailed description of the global lighting subsystem and show how algorithms for path tracing, bidirectional estimators, irradiance caching, hierarchical radiosity, wavelet radiosity, and wavelet radiance have been implemented within Vision View full abstract»

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  • Visualizing network data

    Publication Year: 1995 , Page(s): 16 - 28
    Cited by:  Papers (95)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1248 KB)  

    Networks are critical to modern society, and a thorough understanding of how they behave is crucial to their efficient operation. Fortunately, data on networks is plentiful; by visualizing this data, it is possible to greatly improve our understanding. Our focus is on visualizing the data associated with a network and not on simply visualizing the structure of the network itself. We begin with three static network displays; two of these use geographical relationships, while the third is a matrix arrangement that gives equal emphasis to all network links. Static displays can be swamped with large amounts of data; hence we introduce direct manipulation techniques that permit the graphs to continue to reveal relationships in the context of much more data. In effect, the static displays are parameterized so that interesting views may easily be discovered interactively. The software to carry out this network visualization is called SeeNet View full abstract»

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  • Real time responsive animation with personality

    Publication Year: 1995 , Page(s): 5 - 15
    Cited by:  Papers (75)  |  Patents (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (956 KB)  

    Building on principles from prior work on procedural texture synthesis (K. Perlin, 1985), we are able to create remarkably lifelike, responsively animated characters in real time. Rhythmic and stochastic noise functions are used to define time varying parameters that drive computer generated puppets. Because we are conveying just the “texture” of motion, we are able to avoid computation of dynamics and constraint solvers. The subjective impression of dynamics and other subtle influences on motion can be conveyed with great visual realism by properly tuned expressions containing pseudo random noise functions. For example, we can make a character appear to be dynamically balancing herself, to appear nervous, or to be gesturing in a particular way. Each move has an internal rhythm, and transitions between moves are temporally constrained so that “impossible” transitions are precluded. For example, if while the character is walking we specify a dance turn, the character will always step into the turn onto the correct weight bearing foot. An operator can make a character perform a properly connected sequence of actions, while conveying particular moods and attitudes, merely by pushing buttons at a high level. Potential uses of such high level “textural” approaches to computer graphic simulation include role playing games, simulated conferences, “clip animation”, graphical front ends for MUDs, and synthetic performances View full abstract»

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Aims & Scope

Visualization techniques and methodologies; visualization systems and software; volume visualization; flow visualization; multivariate visualization; modeling and surfaces; rendering; animation; user interfaces; visual progranuning; applications.

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Meet Our Editors

Editor-in-Chief
Leila De Floriani
Department of Computer Science, Bioengineering, Robotics and Systems Engineering
University of Genova
16146 Genova (Italy)
ldf4tvcg@umiacs.umd.edu