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Computer Graphics, Image Processing, and Vision, 1998. Proceedings. SIBGRAPI '98. International Symposium on

Date 20-23 Oct. 1998

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  • Proceedings SIBGRAPI'98. International Symposium on Computer Graphics, Image Processing, and Vision (Cat. No.98EX237)

    Publication Year: 1998
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    Freely Available from IEEE
  • Stroking discrete polynomial Bezier curves via point containment paradigm

    Publication Year: 1998, Page(s):94 - 101
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (235 KB)

    The point containment predicate which specifies if a point is part of a mathematically defined shape or not is a crucial problem in computer graphics. This paper presents a stroking technique that counteracts the main disadvantage of point containment algorithms: their quadratic time complexity with increasing resolution. It is also presented an efficient algorithm to perform simultaneously the fi... View full abstract»

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  • Index of authors

    Publication Year: 1998, Page(s):485 - 486
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    Freely Available from IEEE
  • A constraint-based algorithm for engineering design

    Publication Year: 1998, Page(s):102 - 109
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (460 KB)

    The main focus of this work is on the development of incremental graph-based techniques for satisfying a coupled set of engineering and geometric constraints. The objective is to speed up a constraint-based design. A prototype constraint-based system has been developed to demonstrate the feasibility of these incremental algorithms. The proposed techniques were applied to the internal-combustion en... View full abstract»

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  • Bi-variate pattern spectrum

    Publication Year: 1998, Page(s):476 - 483
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    Bivariate pattern spectrum is the generalization of the concept of usual pattern spectrum. The usual pattern spectrum is the mapping from multidimensional set to 1D vector, whereas bivariate pattern spectrum is the mapping of multidimensional set to 2D vector. The introduction of bivariate pattern spectrum, based upon the geometrical concepts, has the notion to develop a shape-size descriptor, in ... View full abstract»

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  • A system's architecture for warping and morphing of graphical objects

    Publication Year: 1998, Page(s):192 - 199
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    This paper describes a system architecture that enables the use of different techniques of warping and morphing applied to various classes of graphical objects (images, surfaces, plane curves, volumetric data, implicit surfaces etc.) Combinations of warping and morphing techniques can lead to more powerful and expressive results. The possibility of experimenting with alternative techniques for dis... View full abstract»

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  • Directional interpolation pyramids for still image compression

    Publication Year: 1998, Page(s):185 - 190
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (156 KB)

    Reduced pyramids, i.e. pyramids without analysis filters are known to produce excellent results when used for lossless signal and image compression. The paper introduces a novel method for the construction of reduced pyramids with synthesis filters adapted to the orientation of local image features. It is shown that this construction produces more accurate interpolation than conventional reduced p... View full abstract»

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  • An algorithm for intersecting and trimming parametric meshes

    Publication Year: 1998, Page(s):86 - 93
    Cited by:  Patents (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    We present an algorithm for intersecting finite-element meshes defined on parametric surface patches. The intersection curves are modeled precisely and both meshes are adjusted to the newly formed borders. The algorithm is part of an interactive shell modeling program, which has been used in the design of large offshore oil structures. We avoid unacceptable interaction delays by using a variant of... View full abstract»

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  • Morphological image segmentation applied to video quality assessment

    Publication Year: 1998, Page(s):468 - 475
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    This paper presents a methodology to morphological video segmentation used as part of a method to estimate the subjective video quality assessment. The segmentation goal is to partition the sequence frames in three different regions: homogeneous, border and texture. Previous work has shown the importance of computing video impairment measurements to each of these regions separately, in contrast to... View full abstract»

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  • Image compression based on a multipoint Taylor series representation

    Publication Year: 1998, Page(s):174 - 184
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    An image compression/decompression method is proposed, based on a new interpolation formula of Hermite-Birkhoff type. It is based on a function representation that uses a truncated multipoint Taylor (MT) series. Given a regularly tabulated image, first spatial derivatives (up to a chosen order) are computed by a FFT algorithm. Secondly a knot placing strategy selects sample point positions. The im... View full abstract»

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  • Error measures in greedy insertion simplification methods

    Publication Year: 1998, Page(s):78 - 85
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (664 KB)

    In this work we study algorithms for obtaining simplified representations of terrain models. Terrain data is difficult to deal with, due to its complexity and size. Simplification methods are some of the techniques used to reduce its natural complexity. Among these methods, greedy insertion with vertical local error measure is considered to be the one that yields best results. In spite of its qual... View full abstract»

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  • Comparing the influence of color spaces and metrics in content-based image retrieval

    Publication Year: 1998, Page(s):371 - 378
    Cited by:  Papers (4)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (380 KB)

    Visual information retrieval systems have been developed from the necessity of searching and recovering data in libraries with million of daily produced digital images. In image retrieval based on their color content, the distance between color histograms defines usually the matching degree. Results of an image querying depend, at least, on the following features: the underlying color space, the n... View full abstract»

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  • Straight-line removal in boron carbide microscopic images

    Publication Year: 1998, Page(s):462 - 467
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    Boron carbide microscopic images may present grains crossed by twins (or macles) viewed as straight lines in the inner part of each grain. The twins preclude the segmentation because they are very similar to the grain borders. To eliminate the twins a preprocessing step, which relies on mathematical morphology tools, is applied to the image. The main operation used is a directional opening, using ... View full abstract»

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  • Towards perception driven visualization

    Publication Year: 1998, Page(s):127 - 134
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB)

    The use of computer graphics techniques in visualization is hampered by the complexity of data, display limitations and the difficult process of establishing adequate mappings. One way to compensate for the difficulties in handling data and image complexity is to turn to users' capabilities and human factors, and to revisit visualization and interaction techniques under such premises. This paper d... View full abstract»

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  • Image coding using irregular subsampling and Delaunay triangulation

    Publication Year: 1998, Page(s):167 - 173
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    The author proposes an image coding algorithm that effectively combines irregular subsampling and Delaunay triangulation. A set of sampling points in the image is selected in an incremental manner and used to construct a Delaunay triangulation. Each triangular region is then approximated using linear interpolation. The coding scheme is based on run-length coding (RLC). The incremental selection of... View full abstract»

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  • Three-dimensional reconstruction from a set of video cameras of environments for virtual collaboration

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (8 KB)

    In the advent of the ubiquity of distributed computing with multimedia capabilities, it is very natural to contemplate collaborations that were not previously possible. In the past scientists, doctors, educators, engineers always had need to share, exchange, debate their work, designs, methodology, knowledge and experience. This was commonly done by attending meetings, publishing in common journal... View full abstract»

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  • Optimized block based disparity estimation in stereo systems using a maximum-flow approach

    Publication Year: 1998, Page(s):410 - 417
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    A novel disparity estimation method is presented that increases the robustness of the estimator by replacing the classical approach of dynamic programming with finding the maximum flow in a graph. Once solved, the minimum cut associated to the maximum flow yields a disparity surface for the whole image at once. The results show improved depth estimations as well as better handling of depth discont... View full abstract»

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  • A unified geometric model for 3D confocal image analysis in cytology

    Publication Year: 1998, Page(s):69 - 76
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1968 KB)

    In this paper, we use partial differential equation based analysis as a methodology for computer-aided cytology. We wish to accurately extract and classify the shapes of nuclei from noisy confocal microscopy images. This is a prerequisite to an accurate quantitative intranuclear (genotypic and phenotypic) and internuclear (tissue structure) analysis of cancerous and pre-cancerous specimens. We stu... View full abstract»

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  • Automatic feature selection for biological shape classification in Σynergos

    Publication Year: 1998, Page(s):363 - 370
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (80 KB)

    This paper reports the development of a versatile framework allowing the characterization and analysis of computer vision techniques as well as their applications to biological shapes, with attention focused on neural cells. The proposed framework has been implemented within the Σynergos system, a powerful imaging laboratory that includes, among other features, tools for performance assessme... View full abstract»

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  • Virtual seismic interpretation

    Publication Year: 1998, Page(s):119 - 126
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (424 KB)

    This paper presents an application of the virtual reality paradigm to scientific visualization. We describe how the seismic interpretation task performed in oil and gas companies can be facilitated by using immersion techniques inherent to virtual reality. The feeling of immersion allows an easier and better understanding and manipulation of the three-dimensional data associated with seismic inter... View full abstract»

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  • Visualization of geological prospecting data

    Publication Year: 1998, Page(s):142 - 149
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    Oil reservoirs searching is based on several exploratory methods, which produce a large quantity of data that must be interpreted and analyzed by geologists. Graphic systems can help these tasks by providing three-dimensional representations to convey information in a more natural and efficient way to the users. Therefore, they are typical scientific visualization applications. This paper presents... View full abstract»

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  • Load balancing for distributed virtual reality systems

    Publication Year: 1998, Page(s):158 - 165
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1560 KB)

    Due to the concentration of users in certain regions of the virtual world, distributed virtual reality systems-DVRS-may become unbalanced, resulting in low performance and bad utilization of system resources. The authors studied this problem and proposed a queueing model and load balancing algorithms to reduce these effects. Some experiments showed how the utilization and response time of the syst... View full abstract»

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  • Levelings and morphological segmentation

    Publication Year: 1998, Page(s):28 - 35
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (820 KB)

    We present a novel class of morphological filters, which are ideal simplification tools in order to facilitate the segmentation of objects of interest. As a subclass of connected operators, they are particularly interesting for segmentation purposes, as they suppress many details in the image while preserving perfectly the position and the sharpness of the structures which are not suppressed. Furt... View full abstract»

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  • Modeling and analysing computer animations

    Publication Year: 1998, Page(s):18 - 19
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (28 KB)

    Computer animation is a multifaceted field of computer graphics. This presentation explores one of these facets. At first computer animation is surveyed through the use of a framework to help to order and classify its main approaches related to movement modeling. Then the use of Petri nets as a modeling and simulation tool to obtain some kind of foresight of a developed animation is discussed View full abstract»

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  • An approach to physiologically meaningful distributed inverse solutions to the neuro-electromagnetic inverse problem

    Publication Year: 1998, Page(s):332 - 337
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (40 KB)

    The problem of determining the generators of brain electromagnetic activity has no unique solution. The only way to deal this problem, sometimes denominated “the problem of the non-uniqueness”, is to restrict the set of possible solutions by using either physiological or mathematical constraints or a combination of both. The main purpose of this work is to propose a method for obtainin... View full abstract»

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