Proceedings XIV Brazilian Symposium on Computer Graphics and Image Processing

Oct 2001

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Displaying Results 1 - 25 of 87
  • Hybrid human-machine non-linear filter design using envelopes

    Publication Year: 2001, Page(s):106 - 111
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (581 KB) | HTML iconHTML

    Machine design of a signal or image operator involves estimating the optimal filter from sample data. In principle, relative to the error measure used, the optimal filter is best; however, owing to design error, the designed filter might not perform well. In general it is suboptimal. The envelope constraint involves using two humanly designed filters that form a lower and upper bound for the desig... View full abstract»

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  • Microarray gridding by mathematical morphology

    Publication Year: 2001, Page(s):112 - 119
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1088 KB) | HTML iconHTML

    DNA chips (i.e., microarrays) biotechnology is a hybridization (i.e., DNA matching) based process that makes it possible to quantify the relative abundance of mRNA from two distinct samples by analysing their fluorescence signals. This technique requires robotic placement (i.e., spotting) of thousands of cDNAs (i.e., complementary DNA) in an array format on glass microscope slides which provide ge... View full abstract»

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  • Proceedings XIV Brazilian Symposium on Computer Graphics and Image Processing

    Publication Year: 2001
    Request permission for commercial reuse | PDF file iconPDF (326 KB)
    Freely Available from IEEE
  • Segmentation of TEM images using oscillatory neural networks

    Publication Year: 2001, Page(s):289 - 296
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1058 KB) | HTML iconHTML

    Oscillatory neural networks are a relatively recent approach for the problem of image segmentation. Inside of this context, the oscillator neuron of Terman-Wang is presented, which is used as base element of an oscillatory network called LEGION (Locally Excitatory Globally Inhibitory Oscillator Network). The continuous version of the LEGION network, based on a set of differential equations, presen... View full abstract»

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  • Author index

    Publication Year: 2001, Page(s):410 - 411
    Request permission for commercial reuse | PDF file iconPDF (134 KB)
    Freely Available from IEEE
  • Realistic skeletal muscle deformation using finite element analysis

    Publication Year: 2001, Page(s):192 - 199
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB) | HTML iconHTML

    We present a computational model to simulate the skeletal muscle deformation during muscle contraction. This model includes a detailed description of the skeletal muscle architecture, non-linear properties of muscle tissue, novel features in the active muscle constitutive equations, and geometric constraints that can be enforced through Lagrange multipliers. The proposed muscle model predicts fibr... View full abstract»

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  • Interactive digital mirror

    Publication Year: 2001, Page(s):232 - 236
    Cited by:  Papers (1)  |  Patents (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB) | HTML iconHTML

    This paper describes some preliminary results of our ongoing project on digital mirror interfaces. Regular mirrors reflect ambient light from the scene towards the observer. Digital mirrors capture the ambient light with a camera, extract information about the scene, and display appropriate information to the user, combining real-time computer vision systems with realistic computer graphics. We de... View full abstract»

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  • Programming behaviors with local perception and smart objects: an approach to solve autonomous agents tasks

    Publication Year: 2001, Page(s):184 - 191
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1035 KB) | HTML iconHTML

    We propose an integrated framework in which local perception and close manipulation skills are used in conjunction with a high-level behavioral interface based on a "smart object" paradigm as support for a virtual agent to perform autonomous tasks. In our model, virtual "smart objects" encapsulate information about possible interactions between the agent and its environment, including sub-tasks de... View full abstract»

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  • A fast vision-based road following strategy applied to the control of aerial robots

    Publication Year: 2001, Page(s):226 - 231
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (598 KB) | HTML iconHTML

    The utilization of the vision as a feedback sensor in closed-loop control schemes is of great interest, mainly due to the high density of information revealed by images. In this work, we present a method to perform road following tracking by aerial unmanned vehicles (AUV) based on visual input. Difficulties arise from the nonholonomic constraints of the AUV moving in 3D. The problems are overcome ... View full abstract»

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  • Video watermark technique in motion vector

    Publication Year: 2001, Page(s):179 - 182
    Cited by:  Papers (43)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (379 KB) | HTML iconHTML

    In this paper, we propose a video watermarking technique to hide copyright information in MPEG motion vector. In this method, watermark is embedded in larger value motion vectors, and specially in the less phase angle changed component. Then, the motion vector is modified into a new bitstream from which the watermark information can be easily retrieved. From the experimental results, it indicates ... View full abstract»

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  • Enhancing the volumetric approach to stereo matching

    Publication Year: 2001, Page(s):218 - 225
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1428 KB) | HTML iconHTML

    We propose techniques to enhance the volumetric approach to stereo matching, with which to obtain dense disparity and detect occluded zones. The volumetric approach works on the row × column × disparity space initializing the voxels with a measure of the similarity between the stereo pair that they represent (similarity phase). In this phase, we propose a function L0 that pr... View full abstract»

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  • Multi-resolution classification trees in OCR design

    Publication Year: 2001, Page(s):59 - 66
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (659 KB) | HTML iconHTML

    The paper recalls the idea of classification trees in OCR (optical character recognition) systems and proposes a technique for the automatic design of these classification trees. The design of both the classification trees and of the classification operators are based on training from sample pairs of observed-ideal images, allowing the development of customized OCRs View full abstract»

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  • An architecture based on constraints for augmented shared workspaces

    Publication Year: 2001, Page(s):328 - 335
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1169 KB) | HTML iconHTML

    Augmented shared workspaces are an instance of augmented reality which move the collaborative work from the desktop to the real workplace, enabling higher interaction level with coworkers and allowing implementation of advanced techniques of human-machine interfaces. In this paper, we advocate the employment of a constraint system as the document model (or program) for the implementation of augmen... View full abstract»

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  • High-level verification of handwritten numeral strings

    Publication Year: 2001, Page(s):36 - 43
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (556 KB) | HTML iconHTML

    In this paper we discuss the use of high-level verification on handwritten numeral strings. First of all, we introduce the concept of levels of verification and present the baseline system used to carry out the experiments. Two different strategies were developed: absolute and one-to-one verifiers. A thorough error analysis is also presented in order to identify under which conditions high-level v... View full abstract»

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  • Lossless image compression of computerized tomography projections

    Publication Year: 2001
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (85 KB) | HTML iconHTML

    In this paper we apply reversible integer wavelet transform to lossless compression of computerized tomography projections (sinograms). Lossy image compression methods can achieve high compression ratios, but sinograms should not loose information during compression process to not affect the image reconstruction View full abstract»

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  • Adaptive image denoising in scale-space using the wavelet transform

    Publication Year: 2001, Page(s):172 - 178
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1038 KB) | HTML iconHTML

    This paper proposes a new method for image denoising with edge preservation, based on image multiresolution decomposition by a redundant wavelet transform. In our approach, edges are implicitly located and preserved in the wavelet domain, while noise is filtered out. At each resolution, the coefficients associated to noise and coefficients associated to edges are modeled by Gaussians, and a shrink... View full abstract»

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  • Using the Hough transform to detect circular forms in satellite imagery

    Publication Year: 2001
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (65 KB) | HTML iconHTML

    The objective of this work is to identify geological circular forms, impact and volcano craters using satellite images. The recognition of objects (circular forms) is the last step in a processing chain which can be described in four phases: image processing, pattern detection, pattern recognition, and identification of the targets (models). The work presents the detection of circular forms in ima... View full abstract»

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  • Tracing along an intersection closed loop, when should one stop?

    Publication Year: 2001, Page(s):2 - 9
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (897 KB) | HTML iconHTML

    In this paper we present an algorithm for estimating the rotation index of a closed loop from the number of singular points on it. On the basis of this index we also devise a procedure that guarantees to have an arbitrary loop being traced only once. Combining this procedure with a higher-order stepping algorithm, a robust intersection technique is resulted View full abstract»

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  • Wavelet compression of vector field visualizations

    Publication Year: 2001, Page(s):306 - 311
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (441 KB) | HTML iconHTML

    Flow visualization has been an active research field for several years and streamlines have proved to be an effective representation of two-dimensional steady vector fields. Online simulation of complex dynamic systems, computed on powerful computers, become more and more common. Efficient steering of the computational process requires the analysis of simulation results in real time. Visualization... View full abstract»

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  • ARENA and WOXBOT: first steps towards virtual world simulations

    Publication Year: 2001, Page(s):208 - 215
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (717 KB) | HTML iconHTML

    This paper reports new results of a project to build virtual worlds aimed at the graphic simulation of an arena where small mobile robots can perform requested tasks while behaving according to their own motivation and reasoning. Each robot is an intelligent agent that perceives the virtual environment via a simulated vision system and reacts to translating or rotating its body by driving its own ... View full abstract»

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  • On determining a signature for skeletal maturity

    Publication Year: 2001, Page(s):246 - 251
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (602 KB) | HTML iconHTML

    We present a computational framework for semi-automated assessment of skeletal age based on a multi-scale image analysis approach. Through 2D digital X-ray images of the left hand, maturity indicators are searched by means of a two-step process: the user interactively indicates a point inside the middle finger, and the computational method analyzes the image intensity profile along this line, sear... View full abstract»

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  • Automated mammogram classification using a multiresolution pattern recognition approach

    Publication Year: 2001, Page(s):76 - 83
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1261 KB) | HTML iconHTML

    In order to fully achieve automated mammogram analysis one has to tackle two problems: classification of radial, circumscribed microcalcifications, and normal samples; and classification of benign, malignant, and normal samples. How to extract and select the best features from the images for classification is a very difficult task, since all of those classes are basically irregular textures with a... View full abstract»

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  • Improving the original Dual-T-Snakes model

    Publication Year: 2001, Page(s):346 - 353
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (944 KB) | HTML iconHTML

    The dual-t-snakes model plus dynamic programming (DP) techniques is an efficient methodology for boundary extraction and segmentation of 2D images. However, the original proposal of the dual-t-snakes suffers from difficulties for parameters choice and instabilities due to the normal force definition. Also, the proposed method to push a snake way from a local minimum is not efficient for noise imag... View full abstract»

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  • Ongoing learning for supervised pattern recognition

    Publication Year: 2001, Page(s):51 - 58
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (566 KB) | HTML iconHTML

    The paper presents a procedure to implement an automatic system for supervised pattern recognition with an ongoing learning capability. The purpose is to continuously increase the knowledge of the system and, accordingly, to enhance its performance in classification tasks. The nearest neighbor rule is employed as the central classifier and several techniques are added to cope with the increase in ... View full abstract»

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  • Refinement of T-snakes using adaptive parameters

    Publication Year: 2001
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (85 KB) | HTML iconHTML

    T-snake is an active contour able to adapt the initial curve to the object topology. It allows the simultaneous detection of multiple objects with holes and objects fitting one inside another. However, its results depend on an appropriate choice of internal parameters. When the initial T-snake splits, the new snakes use the same initial parameters for smoothed shapes and for small and large high c... View full abstract»

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