10 research outputs found

    Binary image decomposition and compression using mathematical morphology for object recognition

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    Image segmentation has been studied for several years. There are several segmentation techniques which are fast and effective but all of them are lacking the property of invariency to shift, rotation and sizing. In this study a new process is introduced which overcomes the shift, size and rotation variance and the compressed data can be used for object recognition. Euclidean distance measurement is used in the compression process which is rotation invarient but is expensive in terms of time. Eucledean distance transformation is calculated using optimal double two scan algorithm with gray scale morphology, a new method developed by Dr. Shih and Mr. Wu. Mathematical morphology provides an effective tool for image analysis. Many parallel image computers support basic morphological operations. A new image segmentation technique is presented, which is more usefull in object recognition as it is invarient to shif, orientation and is proportional to sized images

    The research for shape-based visual recognition of object categories

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    摘要 视觉目标类识别旨在识别图像中特定的某类目标,基于形状的目标类识别是目前计算机视觉研究的热点之一。真实图像中物体姿态的多样性以及环境的复杂性,给目标的形状提取和识别带来巨大挑战。本文借鉴生物视觉机制的研究成果,对基于形状的目标类识别算法进行研究。主要研究内容如下: 1. 研究与形状认知相关的视觉机制,分析形状知觉整体性的生理基础及其生理模型。以形状知觉整体性为基础,建立基于形状的目标类识别系统框架。框架既重视整体性在自下而上的特征加工中的作用,也重视整体约束在自上而下的识别中的作用。 2. 受生物视觉上的整合野模型启发,本文提出了一个三阶段轮廓检测算法。阶段1利用结构自适应滤波器平滑...Categorical object detection addresses determining the number of instances of a particular object category in an image, and localizing those instances in space and scale. The shape-based visual recognition of object categories is one of hot topics in computer vision. The diversity of poses of targets and complexity of the environment in real images bring huge challenges to shape extraction and obj...学位:工学博士院系专业:信息科学与技术学院自动化系_控制理论与控制工程学号:2322006015337

    Evaluating perceptual maps of asymmetries for gait symmetry quantification and pathology detection

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    Le mouvement de la marche est un processus essentiel de l'activité humaine et aussi le résultat de nombreuses interactions collaboratives entre les systèmes neurologiques, articulaires et musculo-squelettiques fonctionnant ensemble efficacement. Ceci explique pourquoi une analyse de la marche est aujourd'hui de plus en plus utilisée pour le diagnostic (et aussi la prévention) de différents types de maladies (neurologiques, musculaires, orthopédique, etc.). Ce rapport présente une nouvelle méthode pour visualiser rapidement les différentes parties du corps humain liées à une possible asymétrie (temporellement invariante par translation) existant dans la démarche d'un patient pour une possible utilisation clinique quotidienne. L'objectif est de fournir une méthode à la fois facile et peu dispendieuse permettant la mesure et l'affichage visuel, d'une manière intuitive et perceptive, des différentes parties asymétriques d'une démarche. La méthode proposée repose sur l'utilisation d'un capteur de profondeur peu dispendieux (la Kinect) qui est très bien adaptée pour un diagnostique rapide effectué dans de petites salles médicales car ce capteur est d'une part facile à installer et ne nécessitant aucun marqueur. L'algorithme que nous allons présenter est basé sur le fait que la marche saine possède des propriétés de symétrie (relativement à une invariance temporelle) dans le plan coronal.The gait movement is an essential process of the human activity and also the result of coordinated effort between the neurological, articular and musculoskeletal systems. This motivates why gait analysis is important and also increasingly used nowadays for the (possible early) diagnosis of many different types (neurological, muscular, orthopedic, etc.) of diseases. This paper introduces a novel method to quickly visualize the different parts of the body related to an asymmetric movement in the human gait of a patient for daily clinical. The goal is to provide a cheap and easy-to-use method to measure the gait asymmetry and display results in a perceptually relevant manner. This method relies on an affordable consumer depth sensor, the Kinect. The Kinect was chosen because this device is amenable for use in small, confined area, like a living room. Also, since it is marker-less, it provides a fast non-invasive diagnostic. The algorithm we are going to introduce relies on the fact that a healthy walk has (temporally shift-invariant) symmetry properties in the coronal plane

    VLSI Routing for Advanced Technology

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    Routing is a major step in VLSI design, the design process of complex integrated circuits (commonly known as chips). The basic task in routing is to connect predetermined locations on a chip (pins) with wires which serve as electrical connections. One main challenge in routing for advanced chip technology is the increasing complexity of design rules which reflect manufacturing requirements. In this thesis we investigate various aspects of this challenge. First, we consider polygon decomposition problems in the context of VLSI design rules. We introduce different width notions for polygons which are important for width-dependent design rules in VLSI routing, and we present efficient algorithms for computing width-preserving decompositions of rectilinear polygons into rectangles. Such decompositions are used in routing to allow for fast design rule checking. A main contribution of this thesis is an O(n) time algorithm for computing a decomposition of a simple rectilinear polygon with n vertices into O(n) rectangles, preseverving two-dimensional width. Here the two-dimensional width at a point of the polygon is defined as the edge length of a largest square that contains the point and is contained in the polygon. In order to obtain these results we establish a connection between such decompositions and Voronoi diagrams. Furthermore, we consider implications of multiple patterning and other advanced design rules for VLSI routing. The main contribution in this context is the detailed description of a routing approach which is able to manage such advanced design rules. As a main algorithmic concept we use multi-label shortest paths where certain path properties (which model design rules) can be enforced by defining labels assigned to path vertices and allowing only certain label transitions. The described approach has been implemented in BonnRoute, a VLSI routing tool developed at the Research Institute for Discrete Mathematics, University of Bonn, in cooperation with IBM. We present experimental results confirming that a flow combining BonnRoute and an external cleanup step produces far superior results compared to an industry standard router. In particular, our proposed flow runs more than twice as fast, reduces the via count by more than 20%, the wiring length by more than 10%, and the number of remaining design rule errors by more than 60%. These results obtained by applying our multiple patterning approach to real-world chip instances provided by IBM are another main contribution of this thesis. We note that IBM uses our proposed combined BonnRoute flow as the default tool for signal routing

    Geometric Modeling and Recognition of Elongated Regions in Images.

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    The goal of this research is the recovery of elongated shapes from patterns of local features extracted from images. A generic geometric model-based approach is developed based on general concepts of 2-d form and structure. This is an intermediate-level analysis that is computed from groupings and decompositions of related low-level features. Axial representations are used to describe the shapes of image objects having the property of elongatedness. Curve-fitting is shown to compute axial sequences of the points in an elongated cluster. Script-clustering is performed about a parametric smooth curve to extract elongated partitions of the data incorporating constraints of point connectivity, curve alignment, and strip boundedness. A thresholded version of the Gabriel Graph (GG) is shown to offer most of the information needed from the Minimum Spanning Tree (MST) and Delauney Triangulation (DT), while being easily computable from finite neighborhood operations. An iterative curve-fitting method, that is placed in the general framework of Random Sample Consensus (RANSAC) model-fitting, is used to extract maximal partitions. The method is developed for general parametric curve-fitting over discrete point patterns. A complete structural analysis is presented for the recovery of elongated regions from multispectral classification. A region analysis is shown to be superior to an edge-based analysis in the early stages of recognition. First, the curve-fitting method is used to recover the linear components of complex object regions. The rough locations to start and end a region delineation are then detected by decomposing extracted linear shape clusters with a circular operator. Experimental results are shown for a variety of images, with the main result being an analysis of a high-resolution aerial image of a suburban road network. Analyses of printed circuit board patterns and a LANDSAT river image are also given. The generality of the curve-fitting approach is shown by these results and by its possible applications to other described image analysis problems

    Inspection and feature extraction of marine propellers

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997.Includes bibliographical references (p. 93-96).by Michael Oliver Jastram.M.S

    Projeto de operadores de processamento e analise de imagens baseados na transformada imagem-floresta

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    Orientador : Alexandre Xavier FalcãoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoAbstract: In image processing and analysis, many problems can be thought of as an optimal image partition problem based on seed pixels, where each seed defines an influence zone compo­sed by its "closest" pixels. The image foresting transform (1FT) is a unified and efficient approach to solve these problems, by reducing them into a shortest-path forest problem in a graph. It is an extension of previous works on boundary-based image segmenta­tion methods, and it has already been used to design operators for region-based image segmentation, watershed transform and Euclidean distance transformo In this work we add new image processing operators to the 1FT framework, like image segmentation based on fuzzy connectedness, multiscale skeletons and connected operators. We make qualitative and quantitative comparisons with other operators described in the literature, and present some examples in medical imaging and digital video. We also explore some theoretical aspects, such as correctness proofs, complexity analysis and quality assurances of the results of some operatorsResumo: Diversos problemas em processamento e análise de imagens podem ser abordados como um problema de particionamento ótimo de uma imagem baseado em pixels sementes. A transformada imagem-floresta (1FT) se propõe a resolver tais problemas de maneira unificada e eficiente, a partir do cálculo de florestas de caminhos mínimos. Podendo ser considerada uma generalização de trabalhos voltados para a segmentação de imagens baseada em bordas, a 1FT já foi utilizada para segmentação baseada em regiões, cálculo de linhas divisoras de águas e cálculo de transformadas de distância, inclusive baseadas na métrica Euclideana. Neste trabalho acrescentamos novos operadores ao contexto da 1FT, como métodos de segmentação de imagens baseada em conexidade fuzzy, geração de esqueletos multi­escala e operadores conexos. Realizamos comparações qualitativas e quantitativas com outros operadores descritos na literatura, além de apresentar exemplos de aplicações em imagens médicas e em vídeo digital. Exploramos também algumas questões de cunho teórico, como provas de corretude, análises de complexidades computacionais e garantias de qualidade do resultado de alguns métodosMestradoMestre em Ciência da Computaçã

    Modal matching : a method for describing, comparing, and manipulating digital signals

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1995.Includes bibliographical references (leaves 134-144).by Stanley Edward Sclaroff.Ph.D

    Shape classification: towards a mathematical description of the face

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    Recent advances in biostereometric techniques have led to the quick and easy acquisition of 3D data for facial and other biological surfaces. This has led facial surgeons to express dissatisfaction with landmark-based methods for analysing the shape of the face which use only a small part of the data available, and to seek a method for analysing the face which maximizes the use of this extensive data set. Scientists working in the field of computer vision have developed a variety of methods for the analysis and description of 2D and 3D shape. These methods are reviewed and an approach, based on differential geometry, is selected for the description of facial shape. For each data point, the Gaussian and mean curvatures of the surface are calculated. The performance of three algorithms for computing these curvatures are evaluated for mathematically generated standard 3D objects and for 3D data obtained from an optical surface scanner. Using the signs of these curvatures, the face is classified into eight 'fundamental surface types' - each of which has an intuitive perceptual meaning. The robustness of the resulting surface type description to errors in the data is determined together with its repeatability. Three methods for comparing two surface type descriptions are presented and illustrated for average male and average female faces. Thus a quantitative description of facial change, or differences between individual's faces, is achieved. The possible application of artificial intelligence techniques to automate this comparison is discussed. The sensitivity of the description to global and local changes to the data, made by mathematical functions, is investigated. Examples are given of the application of this method for describing facial changes made by facial reconstructive surgery and implications for defining a basis for facial aesthetics using shape are discussed. It is also applied to investigate the role played by the shape of the surface in facial recognition
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