XVIII Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI'05)

9-12 Oct. 2005

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  • XVIII Brazilian Symposium on Computer Graphics and Image Processing [front matter]

    Publication Year: 2005, Page(s):c1 - c11
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  • XVIII Brazilian Symposium on Computer Graphics and Image Processing - Title Page

    Publication Year: 2005, Page(s):i - iii
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  • XVIII Brazilian Symposium on Computer Graphics and Image Processing - Copyright Page

    Publication Year: 2005, Page(s):iv - ivv
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  • XVIII Brazilian Symposium on Computer Graphics and Image Processing - Table of contents

    Publication Year: 2005, Page(s):v - vii
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  • Preface

    Publication Year: 2005, Page(s):viii - viiii
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  • Committees

    Publication Year: 2005, Page(s):ix - xi
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  • list-reviewer

    Publication Year: 2005, Page(s):xii - xv
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  • Image Formation of Multifrequency Vibro-Acoustography: Theory and Computational Simulations

    Publication Year: 2005, Page(s):5 - 12
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1216 KB)

    This paper presents an extension of vibro-acoustography imaging technique. The standard technique relies on the single-frequency dynamic radiation force (or stress) produced by a highly focused dual-frequency ultrasound beam. We propose a multifrequency vibro-acoustography method based on the radiation stress generated by a beam with multiple frequencies. The system point-spread function (PSF) is ... View full abstract»

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  • On the Effect of Relaxation in the Convergence and Quality of Statistical Image Reconstruction for Emission Tomography Using Block-Iterative Algorithms

    Publication Year: 2005, Page(s):13 - 20
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB) | HTML iconHTML

    Relaxation is widely recognized as a useful tool for providing convergence in block-iterative algorithms [1], [2], [6]. In the present article we give new results on the convergence of RAMLA (Row Action Maximum Likelihood Algorithm) [2], filling some important theoretical gaps. Furthermore, because RAMLA and OS-EM (Ordered Subsets - Expectation Maximization) [4] are the algorithms for statistical ... View full abstract»

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  • Content-Based Diagnostic Hysteroscopy Summaries for Video Browsing

    Publication Year: 2005, Page(s):21 - 28
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1176 KB) | HTML iconHTML

    In hospital practice, several diagnostic hysteroscopy videos are produced daily. These videos are continuous (non-interrupted) video sequences, usually recorded in full. However, only a few segments of the recorded videos are relevant from the diagnosis/prognosis point of view, and need to be evaluated and referenced later. This paper proposes a new technique to identify clinically relevant segmen... View full abstract»

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  • True Factor Analysis in Medical Imaging: Dealing with High-Dimensional Spaces

    Publication Year: 2005, Page(s):29 - 36
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB) | HTML iconHTML

    This article presents a new method for discovering hidden patterns in high-dimensional dataset resulting from image registration. It is based on true factor analysis, a statistical model that aims to find clusters of correlated variables. Applied to medical imaging, factor analysis can potentially identify regions that have anatomic significance and lend insight to knowledge discovery and morphome... View full abstract»

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  • Automatic Iris Segmentation Using Active Near Infra Red Lighting

    Publication Year: 2005, Page(s):37 - 43
    Cited by:  Papers (7)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (664 KB) | HTML iconHTML

    This paper introduces a fast, robust and accurate iris segmentation technique based on active lighting. The geometry of the light sources, a single camera and the eye facilitates the detection of the pupil and the automatic selection of the most appropriate image for biometric identification from the video stream, minimizing the effects of noise, distortion and occlusion during the image acquisiti... View full abstract»

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  • Curvature Motion for Union of Balls

    Publication Year: 2005, Page(s):47 - 54
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (496 KB) | HTML iconHTML

    This work proposes a scheme for multi-resolution representation of union of balls in the plane. This representation is inspired by curvature motion for smooth curves. More precisely, the proposed evolution of centres and radii of the balls are based on equations of evolution of the medial axis of a curve that performs curvature motion. The results obtained are very close to the pixel approximation... View full abstract»

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  • Tie-Zone Watershed, Bottlenecks, and Segmentation Robustness Analysis

    Publication Year: 2005, Page(s):55 - 62
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB) | HTML iconHTML

    In a recent paper [1], a new type of watershed (WS) transform was introduced: the tie-zone watershed (TZWS). This region-based watershed transform does not depend on arbitrary implementation and provides a unique (and thereby unbiased) optimal solution. Indeed, many optimal solutions are sometimes possible when segmenting an image by WS. The TZWS assigns each pixel to a catchment basin (CB) if in ... View full abstract»

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  • Binary Image Operator Design Based on Stacked Generalization

    Publication Year: 2005, Page(s):63 - 70
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (576 KB) | HTML iconHTML

    Stacked generalization refers to any learning schema that consists of multiple levels of training. Level zero classifiers are those that depend solely on input data while classifiers at other levels may use the output of lower levels as the input. Stacked generalization can be used to address the difficulties related to the design of image operators defined on large windows. This paper describes a... View full abstract»

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  • A Maximum-Likelihood Approach for Multiresolution W-Operator Design

    Publication Year: 2005, Page(s):71 - 78
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB) | HTML iconHTML

    The design of W-operators from a set of input/output examples for large windows is a hard problem. From the statistical standpoint, it is hard because of the large number of examples necessary to obtain a good estimate of the joint distribution. From the computational standpoint, as the number of examples grows memory and time requirements can reach a point where it is not feasible to design the o... View full abstract»

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  • A Brief Account of the Relations between Gray-Scale Mathematical Morphologies

    Publication Year: 2005, Page(s):79 - 86
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB) | HTML iconHTML

    Mathematical morphology was originally conceived as a set theoretic approach for the processing of binary images. Approaches that extend classical binary morphology to gray-scale images are either based on umbras, thresholds, level sets, or fuzzy sets. Complete lattices form a general framework for all of these approaches. This paper discusses and compares several approaches to gray-scale mathemat... View full abstract»

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  • A Maximum Uncertainty LDA-Based Approach for Limited Sample Size Problems - With Application to Face Recognition

    Publication Year: 2005, Page(s):89 - 96
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (169 KB)

    A critical issue of applying Linear Discriminant Analysis (LDA) is both the singularity and instability of the within-class scatter matrix. In practice, particularly in image recognition applications such as face recognition, there are often a large number of pixels or pre-processed features available, but the total number of training patterns is limited and commonly less than the dimension of the... View full abstract»

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  • Object Detection by K-Connected Seed Competition

    Publication Year: 2005, Page(s):97 - 104
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB) | HTML iconHTML

    The notion of "strength of connectedness" between pixels has been successfully used in image segmentation. We present an extension to these works, which can considerably increase the efficiency of object definition tasks. A set of pixels is said a ê-connected component with respect to a seed pixel when the strength of connectedness of any pixel in that set with respect to the seed is higher t... View full abstract»

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  • Combining Methods to Stabilize and Increase Performance of Neural Network-Based Classifiers

    Publication Year: 2005, Page(s):105 - 111
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (182 KB) | HTML iconHTML

    In this paper we present a set of experiments in order to recognize materials in multispectral images, which were obtained with a tomograph scanner. These images were classified by a neural network based classifier (Multilayer Perceptron) and classifier combining techniques (Bagging, Decision Templates and Dempster-Shafer) were investigated. We also present a performance comparison between the ind... View full abstract»

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  • Ridge-Based Fingerprint Matching Using Hough Transform

    Publication Year: 2005, Page(s):112 - 119
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB) | HTML iconHTML

    Despite the efficacy of minutia-based fingerprint matching techniques for good-quality images captured by optical sensors, minutia-based techniques do not often perform so well on poor-quality images or fingerprint images captured by small solid-state sensors. Solid-state fingerprint sensors are being increasingly deployed in a wide range of applications for user authentication purposes. Therefore... View full abstract»

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  • A Linear Algorithm for Exact Pattern Matching in Planar Subdivisions

    Publication Year: 2005, Page(s):120 - 127
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB) | HTML iconHTML

    Graph sub-isomorphism is a very common approach to solving pattern search problems, but this is a NP-complete problem. This way, it is necessary to invest in research of approximate solutions, or in special cases of the problem. Planar subdivisions can be considered as a special case of graphs, because, in addition to nodes and edges, there is a more rigid topology in relation to the order of the ... View full abstract»

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  • An Improved Linear-Parabolic Model for Lane Following and Curve Detection

    Publication Year: 2005, Page(s):131 - 138
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB) | HTML iconHTML

    In this paper, we propose a new model for lane tracking and curve detection. We use a linear-parabolic model for each lane boundary, and apply constraints to link both lane boundaries based on the expected geometry of the road. The parabolic part of the model, which fits the far field, is then used to analyze the geometry of the road ahead (straight, right curve or left curve), with applications i... View full abstract»

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  • TSD: A Shape Descriptor Based on a Distribution of Tensor Scale Local Orientation

    Publication Year: 2005, Page(s):139 - 146
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (384 KB) | HTML iconHTML

    We present tensor scale descriptor (TSD) — a shape descriptor for content-based image retrieval, registration, and analysis. TSD exploits the notion of local structure thickness, orientation, and anisotropy as represented by the largest ellipse centered at each image pixel and within the same homogeneous region. The proposed method uses the normalized histogram of the local orientation (the ... View full abstract»

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  • Performance Analysis of Oriented Feature Detectors

    Publication Year: 2005, Page(s):147 - 154
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (664 KB) | HTML iconHTML

    Oriented feature detectors are fundamental tools in image understanding, as many images display relevant information in the form of oriented features. Several oriented feature detectors have been developed; some of the important families of oriented feature detectors are steerable filters and Gabor filters. In this work, a performance analysis is presented of the following oriented feature detecto... View full abstract»

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