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

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 unified geometric model for 3D confocal image analysis in cytology

    Publication Year: 1998, Page(s):69 - 76
    Cited by:  Papers (9)
    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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  • 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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  • Morphological algorithms for color images based on a generic-programming approach

    Publication Year: 1998, Page(s):435 - 442
    Cited by:  Papers (3)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1492 KB)

    The main purpose of image processing and analysis is, often, to segment the image into objects in order to analyze the geometrical properties and the structure of the objects and recognize them. The analysis of the geometric objects must be quantitative, because only such an analysis and description of the geometric objects can provide a coherent mathematical framework for describing the spatial o... View full abstract»

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  • A technique for improvement of linear attenuation coefficient maps obtained by means of X-ray tomography in multiple energies

    Publication Year: 1998, Page(s):62 - 68
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (92 KB)

    This study presents a technique for quantitative enhancement of both linear attenuation coefficients and visual features of maps obtained from multiple energies using tomographic systems. The quality of images obtained by computerized X-ray tomography in multiple energies is limited due to the number of noise pixels in the images. The method developed uses enhancement techniques with adaptative fi... 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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  • Two frontiers in morphological image analysis: differential evolution models and hybrid morphological/linear neural networks

    Publication Year: 1998, Page(s):10 - 17
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1292 KB)

    We briefly describe advancements in two broad areas of morphological image analysis. Part I deals with differential morphology and curve evolution. The partial differential equations (PDEs) that model basic morphological operations are first presented. The resulting dilation PDE, numerically implemented by curve evolution algorithms, improves the accuracy of morphological multiscale analysis by Eu... View full abstract»

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  • Reconstructing a 3D model from range images using radial flow model

    Publication Year: 1998, Page(s):54 - 61
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (500 KB)

    The reconstruction of a 3D model from range images can be conveniently split into two stages. The first stage consists basically in the extraction of geometrical information, e.g. the depth and the orientation of image points, and the second stage concentrates on the transformation of these data to a 3D model. We focus on the second stage. Our approach is based on a deformable model, which offers ... View full abstract»

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  • Image-based modeling using a two-step camera calibration method

    Publication Year: 1998, Page(s):388 - 395
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (444 KB)

    We present a two-step camera calibration process based on linear least squares formulations. We show how to apply this process to build an integrated modeling environment, in which a scene is modeled by having the user specify, on a given image, a set of reference points (used for camera calibration) and object points (used for positioning the objects in the scene). Once this has been done, synthe... 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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  • Sonification to support visualization tasks

    Publication Year: 1998, Page(s):150 - 157
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    Computational visualization systems and techniques have improved information gathering activities and changed the ways in which science is studied. However, the complexity of the data handled by such systems has suggested the need for alternative representation and display techniques. Auditory display has been considered to be a real possibility in this area, in a field known as sonification. The ... View full abstract»

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  • Cache management for real time visualization of 2D data sets

    Publication Year: 1998, Page(s):111 - 118
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    We present a general cache management algorithm with data pre-loading that optimizes access to data in real-time applications. We show that our algorithm provides the optimum results when the visualization sequence is known. We also present an oracle that estimates the visualization sequence for 2D data sets, and show the results of the algorithm in a virtual panorama viewer View full abstract»

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  • Pipeline stereo matching in binary images

    Publication Year: 1998, Page(s):426 - 433
    Cited by:  Papers (2)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    In this paper, we present a short review of shape from stereo reconstruction techniques and propose a stereo matching algorithm based on a pipeline approach. At each stage, current positions of match are estimated from previous computed disparities. Determining the best matching only requires the calculus of correlation values of pixels in a small window centered at candidate positions. The algori... View full abstract»

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  • Visual processing throughout the visual field

    Publication Year: 1998, Page(s):2 - 9
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (64 KB)

    This paper summarizes work done in our laboratory with a special emphasis on functional aspects of the visual field. The quality of the perceived image within a visual display depends on the information available within the display itself but also on the capacity of the human visual system to process visual information. Specifically, the paper discusses work on human visual processing which deals ... View full abstract»

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  • Accuracy assessment of a photogrammetric close-range reconstruction system

    Publication Year: 1998, Page(s):46 - 53
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (124 KB)

    Geometric accuracy of a close-range photogrammetric system is assessed in this paper considering surface reconstruction with structured light as its main purpose. The system is based on an off-the-shelf digital camera and a pattern projector. The mathematical model for reconstruction is based on the parametric equation of the projected straight line combined with collinearity equations. A sequenti... View full abstract»

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  • Adaptive speckle MAP filtering for SAR images using statistical clustering

    Publication Year: 1998, Page(s):303 - 310
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1424 KB)

    This paper presents a nonlinear adaptive filter based on the the maximum a posteriori (MAP) approach to reduce speckle in one-look, linear detected SAR images. The k-means clustering algorithm is combined with the MAP filter in order to cluster pixels with similar statistics (Changle Li's variance ratio). Assigned to each cluster there is a window size which is used to estimate the filter paramete... View full abstract»

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  • Estimating vanishing point from the angular correlation of spectral texture distribution

    Publication Year: 1998, Page(s):339 - 345
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    This paper describes a novel method for recovering the perspective geometry of textured surfaces from local spectral analysis. We recover 3-D orientation of planar surfaces based on angular properties of the local spectral description of the surface markings. We also show a geometrical relationship between local spectral components and the vanishing point of the texture plane. Our method is a two-... View full abstract»

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  • Towards optimal ranking metrics

    Publication Year: 1998, Page(s):379 - 386
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    Euclidean metric is frequently used in computer vision, mostly ad-hoc without any justification. However we have found that other metrics like double exponential metric or Cauchy one provide better results, in accordance with the maximum likelihood approach. In this paper we experiment with different modeling functions for similarity noise and compute the accuracy of different methods using these ... 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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  • An algorithm for intersecting and trimming parametric meshes

    Publication Year: 1998, Page(s):86 - 93
    Cited by:  Patents (18)
    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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  • 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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  • Evaluation of three-dimensional reconstructions from arbitrary images

    Publication Year: 1998, Page(s):402 - 409
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (716 KB)

    This paper investigates computer vision techniques for three-dimensional reconstruction having as source of information non-professional images captured from cameras of arbitrary position and orientation. The main purpose is to compose a methodology for 3D reconstruction, aiming specially at its use in the documentation of historic buildings and monuments through their three-dimensional modeling. ... 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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