XII Brazilian Symposium on Computer Graphics and Image Processing (Cat. No.PR00481)

17-20 Oct. 1999

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  • XII Brazilian Symposium on Computer Graphics and Image Processing (Cat. No.PR00481)

    Publication Year: 1999
    Request permission for commercial reuse | PDF file iconPDF (202 KB)
    Freely Available from IEEE
  • Anno 2010-remembering our future. Challenges and frontiers of visualization for Human-Media Technology as the kernel for Human-Centered Computing

    Publication Year: 1999
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (6 KB)

    Summary form only given. Human-Media-Technology is one of the "technology's top 10 challenges and opportunities" for the year 2010. The subject hereby is: "humans live, science finds out how technology conforms." The goal is to develop environments that allow users to cooperate in the most efficient and natural way. Human-centered systems will have to incorporate people as an explicit design compo... View full abstract»

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  • Characterization of linear and morphological operators

    Publication Year: 1999
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    Summary form only given, as follows. In image processing, the transformations of an image to another one are obtained through operators. Among the most important operators are the linear operators and the morphological ones (dilations and erosions). We recall the definition of these operators and present an algebraic characterization of them for the case of spatial invariance. The importance of th... View full abstract»

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  • Accurate building structure recovery from aerial imagery

    Publication Year: 1999
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (3 KB)

    Summary form only given, as follows. In this paper, we discuss methods for the detection and reconstruction of buildings from aerial imagery. These methods have been intended for the analysis of urban and suburban areas and have been applied to images of different resolutions (between 1 m and 10 cm per pixel). Various algorithms for image matching have been investigated, including hierarchical pro... View full abstract»

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  • Index of authors

    Publication Year: 1999, Page(s): 357
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    Freely Available from IEEE
  • Piecewise trilinear deformation of tomographic models

    Publication Year: 1999, Page(s):113 - 122
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    Introduces an iterative method that deforms brain models built from tomographic images. The deformation is used for normalization purposes: individual models are deformed to match the shape, orientation and internal morphology of a reference model. In this method, the individual and the reference models are each enclosed in a cube which is subdivided to form a rectangular grid. The vertices in the... View full abstract»

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  • Fast digital perspective shell rendering

    Publication Year: 1999, Page(s):105 - 111
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    Volume visualization methods usually require extensive storage and time-intensive computations. To make them viable in many applications, researchers have proposed various types of hardware-based and software-based solutions. In most of these solutions, the rendering is based on orthographic parallel projection. However, in applications such as virtual endoscopy, perspective projection is necessar... View full abstract»

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  • Quasi 4-8 subdivision surfaces

    Publication Year: 1999, Page(s):17 - 26
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (752 KB)

    This paper presents a new scheme for subdivision surfaces that is based on four-directional meshes. It combines geometry-sensitive refinement with convolution smoothing. The scheme has a simple, efficient implementation and generates well-shaped meshes which converge to smooth surfaces View full abstract»

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  • Real-time shadow generation using BSP trees and stencil buffers

    Publication Year: 1999, Page(s):93 - 102
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (884 KB)

    This paper describes a real-time shadow generation algorithm for static polygonal environments illuminated by movable point light sources. The algorithm combines a technique of volumetric shadow rendering using stencil buffers with a binary space partitioning (BSP) tree, and includes new easy-to-implement approaches to improvement techniques used in shadow volume algorithms, such as silhouette det... View full abstract»

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  • Design of statistically optimal stack filters

    Publication Year: 1999, Page(s):265 - 274
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    Any gray-scale image can be represented as a “stack” of a decreasing sequence of binary images, obtained by thresholding the gray-scale image at each level. Stack filters are a special class of gray-scale image operators whose filtered images can be represented as the stack of binary images resulting from applying an increasing binary operator for each image of the stack. A classical e... View full abstract»

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  • An optimal algorithm to construct all Voronoi diagrams for k nearest neighbor search in T2

    Publication Year: 1999, Page(s):7 - 15
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    We generalize to the oriented projective plane T2 an algorithm for constructing all order k Voronoi diagrams in the Euclidean plane. We also show that, for fixed k and for a finite set of sites, an order k Voronoi diagram in T2 has an exact number of regions. Furthermore, we show that the order k Voronoi diagram of a set of n sites in T2 is antipodal to its order n... View full abstract»

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  • An image processing and belief network approach to face detection

    Publication Year: 1999, Page(s):177 - 186
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (204 KB)

    This paper describes an approach to face detection, which is the first stage of any fully automated human face recognition system. We propose several enhancements to a feature-based approach described by K.C. Yow and R. Cipolla (1997) in an attempt to obtain more accurate results: namely, the attentive feature selection and grouping phases are modified in order to deal with incomplete feature dete... View full abstract»

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  • Multiple display viewing architecture for virtual environments over heterogeneous networks

    Publication Year: 1999, Page(s):83 - 92
    Cited by:  Papers (4)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (88 KB)

    Visualization systems that support multiple-display viewing can greatly enhance user perception. The common approach to provide multiple synchronized views uses a powerful centralized processing unit to support the rendering process on all screens. As an alternative approach, we propose a distributed architecture that supports a flexible and reliable visualization system that, while giving the use... View full abstract»

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  • Visualizing the unseen body. Architectural potentials of data modeling

    Publication Year: 1999, Page(s):61 - 63
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    The project is a digital architectural visualization of an individual's physiological data in real time. It is both a probing and representational system that brings together science and art through architectural design. Architecture provides the conceptual and visual tools for expressing the complexities of an individual's physiological state. Visualizing the intricate nature of organic life awak... View full abstract»

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  • Automatic design of morphological operators for motion segmentation

    Publication Year: 1999, Page(s):283 - 292
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    A problem of interest in digital video editing is the elimination of moving objects from one video and the introduction of pieces of other videos in their places. A fundamental problem to build computational tools for this purpose is the segmentation of moving objects. The paper approaches this problem with a novel technique based on Beucher-Meyer's paradigm (F. Meyer and S. Beucher, 1990), with m... View full abstract»

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  • The granulometric size density in filter optimization

    Publication Year: 1999, Page(s):257 - 264
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (76 KB)

    Binary granulometric filters are constructed from parameterized unions and intersections of morphological openings. They are especially useful in filtering out clutter when an observed image is composed of a signal unioned with the clutter; however, their general theory does not depend on this model. More generally, the granulometric spectral theory provides a set decomposition in which bands with... View full abstract»

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  • Developing morphological building blocks: from design to implementation

    Publication Year: 1999, Page(s):303 - 311
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    Mathematical morphology has become a widely-used technique for image processing and computer vision. Initially designed as a set theory, it was generalized to the set of gray-scale images and to the complete lattice framework. Despite this accredited theoretical evolution, contemporary practice in morphological algorithm development still lacks a standardized, mathematically rigorous algebraic str... View full abstract»

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  • Keeping an eye for HCI

    Publication Year: 1999, Page(s):171 - 176
    Cited by:  Papers (22)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (112 KB)

    Advanced human-computer interaction (HCI) techniques are required to enhance current computer interfaces. In this paper, we present an eye gaze tracking system based on a robust low-cost real-time pupil detector, and we describe some eye-aware applications that are being developed to enhance HCI. Images of pupils are segmented using an active lighting scheme that exploits very particular propertie... View full abstract»

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  • Efficient visualization of graphical objects

    Publication Year: 1999, Page(s):73 - 81
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (752 KB)

    The use of appropriate data structures for storing sets of graphical objects can lead to great performance improvements in the visualization of large figures, such as maps and CAD drawings. We present a study on the performance of persistent data structures composed of an R-tree and V-trees, for storing and efficiently retrieving 2D graphical objects. Results are shown to demonstrate the efficienc... View full abstract»

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  • Visual tracking of objects using multiresolution

    Publication Year: 1999, Page(s):153 - 160
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    Presents a methodology for multiple object tracking in image sequences at a high video rate using a multi-resolution technique based on the Haar basis of the wavelet transform. The main objective of visual tracking is to closely follow objects in each frame of a video stream such that the object position and other geometric information are always known. The idea is to locate and accompany an objec... View full abstract»

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  • Motion cyclification by time×frequency warping

    Publication Year: 1999, Page(s):49 - 58
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    This paper presents a new algorithm for the cyclification of 1D signals, based on a time×frequency warping. The main goal is to preserve the basic characteristics of the signal, such as low and high frequency regions. The application outlined in this work is the cyclification of motion captured joint curves (near-periodic signals). Also, a method for cyclification of articulated figure motio... View full abstract»

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  • Image data fusion using projection over the set of solutions of an underdetermined least squares problem

    Publication Year: 1999, Page(s):355 - 356
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (60 KB)

    This paper presents a new image data fusion method that aims to combine images with different spatial and spectral resolutions. It is based on a projection onto the subspace of the set of solutions of an underdetermined least squares problem. The data fusion problem may also involve an interpolation process, when images with different spatial resolutions are used. In our case, this interpolation w... View full abstract»

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  • Pitfalls in public key watermarking

    Publication Year: 1999, Page(s):241 - 242
    Cited by:  Papers (2)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    The cryptographic concept of digital signatures is well suited to image watermarking for authentication and integrity verification. However, the peculiar nature of watermarks demands special care in the application of digital signatures for this purpose. We cryptanalyze a recently proposed watermarking scheme and show how it can be strengthened to thwart our attacks, exploring the use of hashing f... View full abstract»

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  • Control point assessment for image registration

    Publication Year: 1999, Page(s):125 - 132
    Cited by:  Papers (2)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    Presents several extensions of the basic control point assessment (CPA) algorithm. First, we compare CPA to standard corner detection algorithms and then turn to the question of selecting control points with adequate dispersion, since this is crucial for accurate registration. Two selection methods are proposed. The first consists of clustering the control points via the Lloyd algorithm (S.P. Lloy... View full abstract»

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  • Mesh collapse compression

    Publication Year: 1999, Page(s):27 - 28
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (72 KB)

    We present a novel algorithm for encoding the topology of triangular meshes. A sequence of edge contract and divide operations collapses the entire mesh into a single vertex. This implicitly creates a tree with weighted edges. The weights are vertex degrees and capture the topology of the unlabeled mesh. The nodes are vertices and capture the labeling of the mesh. This weighted-edge tree has a ver... View full abstract»

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