246 research outputs found

    Time Critical Lumigraph Rendering

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    It was illustrated in 1996 that the light leaving the convex hull of an object (or entering a convex region of empty space) can be fully characterized by a 4D function over the space of rays crossing a surface surrounding the object (or surrounding the empty space). Methods to represent this function and quickly render individual images from this representation given an arbitrary cameras were also described. This paper extends the work outlined by (Gortler et al) by demonstrating a taxonomy of methods to accelerate the rendering process by trading off quality for time. Given the specific limitation of a given hardware configuration, we discuss methods to tailor a critical time rendering strategy using these methods.Engineering and Applied Science

    Unstructured light fields

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 35-38).We present a system for interactively acquiring and rendering light fields using a hand-held commodity camera. The main challenge we address is assisting a user in achieving good coverage of the 4D domain despite the challenges of hand-held acquisition. We define coverage by bounding reprojection error between viewpoints, which accounts for all 4 dimensions of the light field. We use this criterion together with a recent Simultaneous Localization and Mapping technique to compute a coverage map on the space of viewpoints. We provide users with real-time feedback and direct them toward under-sampled parts of the light field. Our system is lightweight and has allowed us to capture hundreds of light fields. We further present a new rendering algorithm that is tailored to the unstructured yet dense data we capture. Our method can achieve piecewise-bicubic reconstruction using a triangulation of the captured viewpoints and subdivision rules applied to reconstruction weights.by Myers Abraham Davis (Abe Davis).S.M

    Polyhedral Geometry and the Two-plane Parameterization

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    Recently the light-ļ¬eld and lumigraph systems have been proposed as general methods of representing the visual information present in a scene. These methods represent this information as a 4D function of light over the domain of directed lines. These systems use the intersection points of the lines on two planes to parameterize the lines in space. This paper explores the structure of the two-plane parameterization in detail. In particular we analyze the association between the geometry of the scene and subsets of the 4D data. The answers to these questions are essential to understanding the relationship between a lumigraph, and the geometry that it attempts to represent. This knowledge is potentially important for a variety of applications such as extracting shape from lumigraph data, and lumigraph compression.Engineering and Applied Science

    Parallel lumigraph reconstruction

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    Journal ArticleThis paper presents three techniques for reconstructing Lumigraphs/ Lightfields on commercial ccNUMA parallel distributed shared memory computers. The first method is a parallel extension of the software-based method proposed in the Lightfield paper. This expands the ray/two-plane intersection test along the film plane, which effectively becomes scan conversion. The second method extends this idea by using a shear/warp factorization that accelerates rendering. The third technique runs on an SGI Reality Monster using up to eight graphics pipes and texture mapping hardware to reconstruct images. We characterize the memory access patterns exhibited using the hardware-based method and use this information to reconstruct images from a tiled UV plane. We describe a method to use quad-cubic reconstruction kernels. We analyze the memory access patterns that occur when viewing Lumigraphs. This allows us to ascertain the cost/benefit ratio of various tilings of the texture plane

    Survey of image-based representations and compression techniques

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    In this paper, we survey the techniques for image-based rendering (IBR) and for compressing image-based representations. Unlike traditional three-dimensional (3-D) computer graphics, in which 3-D geometry of the scene is known, IBR techniques render novel views directly from input images. IBR techniques can be classified into three categories according to how much geometric information is used: rendering without geometry, rendering with implicit geometry (i.e., correspondence), and rendering with explicit geometry (either with approximate or accurate geometry). We discuss the characteristics of these categories and their representative techniques. IBR techniques demonstrate a surprising diverse range in their extent of use of images and geometry in representing 3-D scenes. We explore the issues in trading off the use of images and geometry by revisiting plenoptic-sampling analysis and the notions of view dependency and geometric proxies. Finally, we highlight compression techniques specifically designed for image-based representations. Such compression techniques are important in making IBR techniques practical.published_or_final_versio

    Design of Immersive Online Hotel Walkthrough System Using Image-Based (Concentric Mosaics) Rendering

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    Conventional hotel booking websites only represents their services in 2D photos to show their facilities. 2D photos are just static photos that cannot be move and rotate. Imagebased virtual walkthrough for the hospitality industry is a potential technology to attract more customers. In this project, a research will be carried out to create an Image-based rendering (IBR) virtual walkthrough and panoramic-based walkthrough by using only Macromedia Flash Professional 8, Photovista Panorama 3.0 and Reality Studio for the interaction of the images. The web-based of the image-based are using the Macromedia Dreamweaver Professional 8. The images will be displayed in Adobe Flash Player 8 or higher. In making image-based walkthrough, a concentric mosaic technique is used while image mosaicing technique is applied in panoramic-based walkthrough. A comparison of the both walkthrough is compared. The study is also focus on the comparison between number of pictures and smoothness of the walkthrough. There are advantages of using different techniques such as image-based walkthrough is a real time walkthrough since the user can walk around right, left, forward and backward whereas the panoramic-based cannot experience real time walkthrough because the user can only view 360 degrees from a fixed spot
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