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Computer Graphics and Applications, IEEE

Issue 2 • Date March-April 2002

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Displaying Results 1 - 11 of 11
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  • Image-based lighting

    Page(s): 26 - 34
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    This tutorial shows how image-based lighting can illuminate synthetic objects with measurement of real light, making objects appear as if they're actually in a real world scene. View full abstract»

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  • Quartic discriminants and tensor invariants

    Page(s): 86 - 91
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1012 KB)  

    Discusses the calculation of discriminants of polynomials. The discriminant is a function of the coefficients that indicates if the polynomial has any double roots. The discriminant Δ4 of a homogeneous quartic f(x,w) = Ax4+4Bx3w+6Cx2 w2+4Dxw3+Ew4 = 0 is Δ4 = 27(I3)2-(I2)3, where I2 = AE-4BD+3C2 and I3 = ACE-AD 2-B2E+2BCD-C3 (this is the Hilbert representation). The author shows how to write the discriminant as a tensor diagram. The discriminant of a polynomial is an example of an invariant quantity. Tensor diagrams are particularly useful to express invariant quantities. Adding a dimension moves us from the world of (1D) homogeneous polynomials to 2D homogeneous (2DH) geometry (curves in the projective plane). It is shown that a relationship exists between the possible root structures of a 4th-order polynomial and the possible degeneracies of a 3rd-order curve View full abstract»

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  • Perception and painting: a search for effective, engaging visualizations

    Page(s): 10 - 15
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    Scientific visualization represents information as images that let us explore, discover, analyze and validate large collections of data. Much research in this area is dedicated to designing effective visualizations that support specific analysis needs. Recently, though, we've considered visualizations from another angle. We've started asking, "Are visualizations beautiful? Can we consider visualizations works of art?" You might expect answers to these questions to vary widely depending on an individual's interpretation what it means to be artistic. We believe that the issues of effectiveness and aesthetics may not be as independent as they seem initially. We can learn much from studying two related disciplines - human psychophysics and art theory and history. Human psychophysics teaches us how we see the world around us. Art history shows us how artistic masters capture our attention by designing works that evoke an emotional response. The common interest in visual attention provides an important bridge between these domains. We're using this bridge to produce effective and engaging visualizations, and in this article, we share some of the lessons we've learned along the way View full abstract»

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  • Interactive pop-up card design. 2

    Page(s): 74 - 85
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4183 KB)  

    Pop-up cards are fun to create and receive. They're also a great output medium for computer graphics, offering an economic and compact way to show 3D scenes without the need for special glasses, shutters or any other electronic hardware. Two basic pop-up mechanisms - the single-slit and the V-fold - are the heart of my interactive pop-up design assistant, which I use to design cards on the computer that I then print out and assemble. Happily, these two mechanisms are also among the most general of all techniques used in pop-ups, since many of the other constructions are combinations of these mechanisms or variations on their geometry. Of course, a variety of pop-up mechanisms exist that aren't captured by those ideas. Happily, most of those are straightforward to design and create with special-purpose code and don't present the sort of design challenges that the slit and V-fold designs do View full abstract»

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  • Image-based crowd rendering

    Page(s): 36 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4694 KB)  

    Populated virtual urban environments are important in many applications, from urban planning to entertainment. At the current stage of technology, users can interactively navigate through complex, polygon-based scenes rendered with sophisticated lighting effects and high-quality antialiasing techniques. As a result, animated characters (or agents) that users can interact with are also becoming increasingly common. However, rendering crowded scenes with thousands of different animated virtual people in real time is still challenging. To address this, we developed an image-based rendering approach for displaying multiple avatars. We take advantage of the properties of the urban environment and the way a viewer and the avatars move within it to produce fast rendering, based on positional and directional discretization. To display many different individual people at interactive frame rates, we combined texture compression with multipass rendering View full abstract»

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  • Real-time video-based modeling and rendering of 3D scenes

    Page(s): 66 - 73
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    Our work targets 3D scenes in motion. In this article, we propose a method for view-dependent layered representation of 3D dynamic scenes. Using densely arranged cameras, we've developed a system that can perform processing in real time from image pickup to interactive display, using video sequences instead of static images, at 10 frames per second. In our system, images on layers are view dependent, and we update both the shape and image of each layer in real time. This lets us use the dynamic layers as the coarse structure of the dynamic 3D scenes, which improves the quality of the synthesized images. In this sense, our prototype system may be one of the first full real-time image -based modelling and rendering systems. Our experimental results show that this method is useful for interactive 3D rendering of real scenes View full abstract»

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  • Automated mosaics via topology inference

    Page(s): 44 - 54
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    The authors present a complete approach for the automated construction of mosaics from images and video using topology inference, local and global alignment, and compositing View full abstract»

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  • Example-based super-resolution

    Page(s): 56 - 65
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    We call methods for achieving high-resolution enlargements of pixel-based images super-resolution algorithms. Many applications in graphics or image processing could benefit from such resolution independence, including image-based rendering (IBR), texture mapping, enlarging consumer photographs, and converting NTSC video content to high-definition television. We built on another training-based super-resolution algorithm and developed a faster and simpler algorithm for one-pass super-resolution. Our algorithm requires only a nearest-neighbor search in the training set for a vector derived from each patch of local image data. This one-pass super-resolution algorithm is a step toward achieving resolution independence in image-based representations. We don't expect perfect resolution independence-even the polygon representation doesn't have that-but increasing the resolution independence of pixel-based representations is an important task for IBR View full abstract»

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  • Computer graphics: helping to cope with terrorism

    Page(s): 16 - 23
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    The fist-to-the-gut impact that graphics and images have was driven home to millions of people around the world on 11 September 2001. As graphics professionals, we can take some pride in how we used computer graphics technology in many aspects of the ensuing response. In an emergency, we don't have time to develop new technology. Finding new ways to use what you have and leveraging available technology is what happens. This article describes how computer graphics imaging technology helped us comprehend the incomprehensible and saved lives, is helping and assisting to memorialize the victims, and will assist in the rebuilding that's being planned View full abstract»

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  • Augmenting elementary school education with VR

    Page(s): 6 - 9
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    At the University of Illinois at Chicago's Electronic Visualization Laboratory, we use virtual reality technology to complement real-world experiences rather than replace them. For more than two years, we've been deploying ImmersaDesk applications in a Chicago-area elementary school. We want to know whether these virtual environments (VEs) help children make sense of mathematics and scientific phenomena. If so, can educators adapt them to the realities of elementary school learning and teaching? Our experience indicates that VR can successfully augment scientific education as well as help to equalize the learning environment by engaging students of all levels View full abstract»

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IEEE Computer Graphics and Applications bridges the theory and practice of computer graphics.

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Meet Our Editors

Editor-in-Chief
L. Miguel Encarnação
University of Iowa