2008 XXI Brazilian Symposium on Computer Graphics and Image Processing最新文献

A Backmapping Approach for Graph-Based Object Tracking 一种基于图的目标跟踪反映射方法

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.32

T. M. Paixão, Ana Beatriz Vicentim Graciano, R. M. C. Junior, R. Hirata

{"title":"A Backmapping Approach for Graph-Based Object Tracking","authors":"T. M. Paixão, Ana Beatriz Vicentim Graciano, R. M. C. Junior, R. Hirata","doi":"10.1109/SIBGRAPI.2008.32","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2008.32","url":null,"abstract":"Model-based methods play a central role to solve different problems in computer vision. A particular important class of such methods rely on graph models where an object is decomposed into a number of parts, each one being represented by a graph vertex. A graph model-based tracking algorithm has been recently introduced in which a model is generated for a given frame (reference frame) and used to track a target object in the subsequent ones. Because the view of an object changes along the video sequence, the solution updated the model using affine transformations. This paper proposes a different approach and improves the previous one in several ways. Firstly, instead of updating the model, each analyzed frame is backmapped to the model space, thus providing more robustness to the method because model parameters do not have to be modified. A different method for model generation based on user traces has also been implemented and used. This model generation approach is much simpler and user-friendly. Finally, a graph-matching algorithm that has been recently proposed is used for object tracking. This new algorithm is more efficient and leads to better matching results. Experimental results using synthetic and real sequences from the CAVIAR project are shown and discussed.","PeriodicalId":330622,"journal":{"name":"2008 XXI Brazilian Symposium on Computer Graphics and Image Processing","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121977690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Occlusion Handling for Object Tracking Using a Fast Level Set Method 使用快速水平集方法进行对象跟踪的遮挡处理

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.36

J. Gambini, Damian Rozichner, M. Buemi, M. Mejail, J. Jacobo-Berlles

{"title":"Occlusion Handling for Object Tracking Using a Fast Level Set Method","authors":"J. Gambini, Damian Rozichner, M. Buemi, M. Mejail, J. Jacobo-Berlles","doi":"10.1109/SIBGRAPI.2008.36","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2008.36","url":null,"abstract":"Tracking objects in image sequences is a difficult problem because of the frequent occlusions encountered among the objects and people. In this paper, a method for tracking objects through occlusions based on a level set technique, is presented. Two ca.ses are considered: 1-the object is obstructed by another one of a different color. 2-the object is obstructed by another one of the same color.In the first case, the classical algorithms based on active contours fail to track the object's contour because the curve disappears from the scene. In this proposal, occlusion is detected and the solution is based on keeping the curve in the same place until the object of interest appears in the scene again.In the second case, the classic algorithms based on active contours do not distinguish between two image objects of the same color, so due to the possible changes in the topology, the curve fits the edge of both objects and it is divided. We solve this problem by means of localizing the centroid of the curve.The experimental results show that these methods significantly improve the tracking with occlusions.","PeriodicalId":330622,"journal":{"name":"2008 XXI Brazilian Symposium on Computer Graphics and Image Processing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128239645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Tradeoffs in Approximate Range Searching Made Simpler 近似范围搜索的权衡变得更简单

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.24

S. Arya, G. D. D. Fonseca, D. Mount

引用次数: 6

Matching Photometric Observation Vectors with Shadows and Variable Albedo 具有阴影和可变反照率的光度观测向量匹配

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.39

H. C. G. Leitão, R. Saracchini, J. Stolfi

引用次数: 6

Color Descriptors for Web Image Retrieval: A Comparative Study 用于网络图像检索的颜色描述符:比较研究

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.20

O. A. B. Penatti, R. Torres

引用次数: 32

An Automatic Crude Registration of Two Partially Overlapping Range Images 两幅部分重叠距离图像的自动粗配准

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.27

M. Márquez, Shin-Ting Wu

引用次数: 2

Automatic Produce Classification from Images Using Color, Texture and Appearance Cues 自动产生分类从图像使用颜色，纹理和外观线索

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.9

A. Rocha, D. C. Hauagge, Jacques Wainer, S. Goldenstein

引用次数: 24

New Higher-Resolution Discrete Euclidean Medial Axis in nD with Linear Time Parallel Algorithm 基于线性时间并行算法的nD中高分辨率离散欧几里得中轴线

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.38

A. Saúde

{"title":"New Higher-Resolution Discrete Euclidean Medial Axis in nD with Linear Time Parallel Algorithm","authors":"A. Saúde","doi":"10.1109/SIBGRAPI.2008.38","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2008.38","url":null,"abstract":"The notion of skeleton plays a major role in shape analysis since the introduction of the medial axis. The continuous medial axis is a skeleton with the following characteristics: centered, thin, homotopic, and reversible (sufficient for the reconstruction of the original object). The discrete Euclidean medial axis (MA) is also reversible and centered, but no longer homotopic nor thin. To preserve topology and reversibility, the MA is usually combined with homotopic thinning algorithms. Since there is a robust and well defined framework for fast homotopic thinning defined in the domain of abstract complexes, some authors have extended the MA to a doubled resolution grid and defined the discrete Euclidean Medial Axis in Higher Resolution (HMA), which can be combined to the framework defined on abstract complexes. Other authors gave an alternative definition of medial axis, which is a reversible subset of the MA, and is called Reduced Discrete Medial Axis (RDMA). The RDMA is thinner than the MA and can be computed in optimal time. In this paper we extend the RDMA to the doubled resolution grid and we define the High-resolution RDMA (HRDMA). The HRDMA is reversible and it can be computed in optimal time. The HRDMA can be combined with the algorithms in abstract complexes, so a reversible and homotopic Euclidean skeleton can be computed in optimal time.","PeriodicalId":330622,"journal":{"name":"2008 XXI Brazilian Symposium on Computer Graphics and Image Processing","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130295063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Approximations by Smooth Transitions in Binary Space Partitions 二元空间分区中平滑过渡的近似

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.7

Marcos Lage, A. Bordignon, Fabiano Petronetto, Alvaro Veiga, G. Tavares, T. Lewiner, H. Lopes

引用次数: 4

Evaluation of Five Algorithms for Mapping Brain Cortical Surfaces 五种脑皮层表面映射算法的评价

2008 XXI Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2008-10-12 DOI: 10.1109/SIBGRAPI.2008.16

S. Eskildsen, L. Østergaard

{"title":"Evaluation of Five Algorithms for Mapping Brain Cortical Surfaces","authors":"S. Eskildsen, L. Østergaard","doi":"10.1109/SIBGRAPI.2008.16","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2008.16","url":null,"abstract":"With the increasing resolution and contrast of brain imaging devices automatic segmentation and quantification of the human cerebral cortex have grown popular for morphological analyses. The tightly folded cortex is often modeled with surfaces in 3D, and morphological features, such as the cortical thickness, can be calculated. In order to average and compare such morphological features within groups of subjects, mappings between the highly diverse cortical surfaces are needed. In this paper we evaluate five algorithms for mapping between discrete polygonal surfaces of cortices. Among the evaluated algorithms we include a new algorithm based on a functional expressing similarity between geometrical features. Four numerical mapping criteria, a landmark test, and statistical maps are used to evaluate the mapping algorithms. We show that the accuracy of manually placed landmarks are difficult to reproduce automatically, and the choice of mapping algorithm impacts the conclusions drawn from statistical maps generated by use of the algorithm. In terms of landmark accuracy, a spherical mapping approach with non-linear optimization is shown to be the best of the tested algorithms.","PeriodicalId":330622,"journal":{"name":"2008 XXI Brazilian Symposium on Computer Graphics and Image Processing","volume":"379 7-8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120890907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20