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XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)最新文献

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Improvement in SAR Image Classification using Adaptive Stack Filters 自适应叠加滤波器在SAR图像分类中的改进
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.40
M. Buemi, M. Mejail, J. Jacobo-Berlles, J. Gambini
{"title":"Improvement in SAR Image Classification using Adaptive Stack Filters","authors":"M. Buemi, M. Mejail, J. Jacobo-Berlles, J. Gambini","doi":"10.1109/SIBGRAPI.2007.40","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.40","url":null,"abstract":"Stack filters are a special case of non-linear filters. They have a good performance for filtering images with different types of noise while preserving edges and details. A stack filter decomposes an input image into several binary images according to a set of thresholds. Each binary image is filtered by a Boolean function. The Boolean function that characterizes an adaptive stack filter is optimal and is computed from a pair of images consisting of an ideal noiseless image and its noisy version. In this work the behavior of adaptive stack filters is evaluated for the classification of synthetic aperture radar (SAR) images, which are affected by speckle noise. With this aim it was carried out experiment in which simulated and real images are generated and then filtered with a stack filter trained with one of them. The results of their maximum likelihood classification are evaluated and then are compared with the results of classifying the images without previous filtering.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"423 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115856454","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: 5
Local Scale for Boundary Shape Description: Application in Locating Landmarks Automatically 边界形状描述局部比例尺在地标自动定位中的应用
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.11
S. Rueda, J. Udupa, L. Bai
{"title":"Local Scale for Boundary Shape Description: Application in Locating Landmarks Automatically","authors":"S. Rueda, J. Udupa, L. Bai","doi":"10.1109/SIBGRAPI.2007.11","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.11","url":null,"abstract":"A good shape descriptor is necessary for automatically identifying landmarks on boundaries. Our method of boundary shape description is based on the notion of c- scale, which is a new local scale concept, defined at each boundary element. From this representation we can extract special points of interest such as convex and concave corners, straight lines, circular segments, and inflection points. The results show that this method gives a complete description of shape and allows the automatic positioning of mathematical landmarks, which agree with our intuitive ideas of where landmarks may be defined. This method is applicable to spaces of any dimensionality, although we have focused in this paper on 2D shapes.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124534985","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: 6
A Restoration and Extrapolation Iterative Method for Band-limited Fluorescence Microscopy Image 一种带限荧光显微图像的恢复和外推迭代方法
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.25
M. Ponti, N. Mascarenhas, C. Suazo
{"title":"A Restoration and Extrapolation Iterative Method for Band-limited Fluorescence Microscopy Image","authors":"M. Ponti, N. Mascarenhas, C. Suazo","doi":"10.1109/SIBGRAPI.2007.25","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.25","url":null,"abstract":"Optical microscopic images, especially with a nonconfocal microscope, are fundamentally limited because the optical transfer function (the Fourier transform of the point-spread function) is zero over a region of the spatial-frequency domain. Iterative algorithms were developed for the restoration and extrapolation of diffraction-limited imagery. In this paper we present the effectiveness of an iterative method based on the Richardson-Lucy algorithm for image restoration and a simultaneous modified version of Gerchberg-Papoulis method to extrapolate the spectrum and control the noise amplification. Good convergence stabilization results were achieved and also good numerical results were observed.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"389 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116151924","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
Memory-Aware and Efficient Ray-Casting Algorithm 内存感知和高效的光线投射算法
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.28
Saulo Ribeiro, André Maximo, C. Bentes, Antonio A. F. Oliveira, R. Farias
{"title":"Memory-Aware and Efficient Ray-Casting Algorithm","authors":"Saulo Ribeiro, André Maximo, C. Bentes, Antonio A. F. Oliveira, R. Farias","doi":"10.1109/SIBGRAPI.2007.28","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.28","url":null,"abstract":"Ray-casting implementations require that the connectivity between the cells of the dataset to be explicitly computed and kept in memory. This constitutes a huge obstacle for obtaining real-time rendering for very large models. In this paper, we address this problem by introducing a new implementation of the ray-casting algorithm for irregular datasets. Our implementation optimizes the memory usage of past implementations by exploring ray coherence. The idea is to keep in main memory the information of the faces traversed by the ray cast through every pixel under the projection of a visible face. Our results show that exploring pixel coherence reduces considerably the memory usage, while keeping the performance of our algorithm competitive with the fastest previous ones.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121223932","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: 12
White blood cell segmentation using morphological operators and scale-space analysis 基于形态学算子和尺度空间分析的白细胞分割
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.33
L. Dorini, R. Minetto, N. J. Leite
{"title":"White blood cell segmentation using morphological operators and scale-space analysis","authors":"L. Dorini, R. Minetto, N. J. Leite","doi":"10.1109/SIBGRAPI.2007.33","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.33","url":null,"abstract":"Cell segmentation is a challenging problem due to both the complex nature of the cells and the uncertainty present in video microscopy. Manual methods for this purpose are onerous, imprecise and highly subjective, thus requiring automated methods that perform this task in an objective and efficient way. In this paper, we propose a novel method to segment nucleus and cytoplasm of white blood cells (WBC). WBC composition of the blood provides important information to doctors and plays an important role in the diagnosis of different diseases. We use simple morphological operators and explore the scale-space properties of a toggle operator to improve the segmentation accuracy. The proposed scheme has been successfully applied to a large number of images, showing promising results for varying cell appearance and image quality, encouraging future works.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"50 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127997868","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: 149
Graph-based Object Tracking Using Structural Pattern Recognition 使用结构模式识别的基于图的目标跟踪
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.43
Ana Beatriz Vicentim Graciano, R. M. C. Junior, I. Bloch
{"title":"Graph-based Object Tracking Using Structural Pattern Recognition","authors":"Ana Beatriz Vicentim Graciano, R. M. C. Junior, I. Bloch","doi":"10.1109/SIBGRAPI.2007.43","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.43","url":null,"abstract":"This paper proposes a model-based methodology for recognizing and tracking objects in digital image sequences. Objects are represented by attributed relational graphs (or ARGs), which carry both local and relational information about them. The recognition is performed by inexact graph matching, which consists in finding an approximate homomorphism between ARGs derived from an input video and a model image. Searching for a suitable homomorphism is achieved through a tree-search optimization algorithm and the minimization of a pre-defined cost function. Motion smoothness between successive frames is exploited to achieve the recognition over the whole sequence, with improved spatio-temporal coherence.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134179663","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: 45
Two-stage Binary Image Operator Design: an Approach Based on Interaction Information 基于交互信息的两阶段二值图像算子设计
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.24
C. S. Santos, N. Hirata, R. Hirata
{"title":"Two-stage Binary Image Operator Design: an Approach Based on Interaction Information","authors":"C. S. Santos, N. Hirata, R. Hirata","doi":"10.1109/SIBGRAPI.2007.24","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.24","url":null,"abstract":"We address the problem of binary image operator design over large windows by breaking it into two phases. Firstly, we design several operators over small sub-windows of the main window. The outputs of these first level operators are then combined into a global operator. We devise a heuristic, motivated by Information Theory, for breaking the main window into sub-windows. Preliminary results show that the proposed scheme improves operator performance over single-level operators.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133490706","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: 2
Improved Real-Time Shadow Mapping for CAD Models 改进的CAD模型实时阴影映射
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.36
V. Barroso, Waldemar Celes Filho
{"title":"Improved Real-Time Shadow Mapping for CAD Models","authors":"V. Barroso, Waldemar Celes Filho","doi":"10.1109/SIBGRAPI.2007.36","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.36","url":null,"abstract":"Shadow mapping is a widely used rendering technique for real-time shadow generation. However, it may produce jagged shadow borders and incorrect self-shadowing artifacts. When applied to CAD (computer-aided design) models, it presents additional challenges due to the existence of thin and complex-silhouette objects, high depth range, and high depth complexity. In this work, we present a short survey of shadow mapping algorithms and investigate their suitability to CAD model rendering. We also present two improvements to existing techniques: a generalized parameter for LiSPSMs (light-space perspective shadow maps) and an adaptive z-partitioning scheme.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"178 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115696848","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: 5
Automated Segmentation of the Corpus Callosum Midsagittal Surface Area 胼胝体正中矢状面区域的自动分割
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.29
F. Seixas, A. S. Souza, A. A. S. D. Santos, D. Muchaluat-Saade
{"title":"Automated Segmentation of the Corpus Callosum Midsagittal Surface Area","authors":"F. Seixas, A. S. Souza, A. A. S. D. Santos, D. Muchaluat-Saade","doi":"10.1109/SIBGRAPI.2007.29","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.29","url":null,"abstract":"The non-invasive in vivo nature of magnetic resonance imaging (MRI) makes it the modality of choice of many neuroanatomical imaging studies. This paper discusses automatic brain structure segmentation based on previous knowledge on statistical models. The method is validated by an experiment involving magnetic resonance images acquired from 20 healthy adult individuals (10 men and 10 women). The results provide normative data of the midsagittal surface area of the corpus callosum from a 46-55 years old range group, splitting results by gender. Our results were also compared with data obtained from other authors, validating the correlation between brain volume and the area of this structure. The final goal of this work is computer-aided diagnosis for brain diseases.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124851403","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: 7
Geodesic Bezier Curves: a Tool for Modeling on Triangulations 测地线贝塞尔曲线:一个在三角剖分上建模的工具
XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007) Pub Date : 2007-10-07 DOI: 10.1109/SIBGRAPI.2007.38
D. M. Morera, P. Carvalho, L. Velho
{"title":"Geodesic Bezier Curves: a Tool for Modeling on Triangulations","authors":"D. M. Morera, P. Carvalho, L. Velho","doi":"10.1109/SIBGRAPI.2007.38","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2007.38","url":null,"abstract":"We define a new class of curves, called geodesic Bezier curves, that are suitable for modeling on manifold triangulations. As a natural generalization of Bezier curves, the new curves are as smooth as possible. We discuss the construction of C0 and C1 piecewise Bezier splines. We also describe how to perform editing operations, such as trimming, using these curves. Special care is taken to achieve interactive rates for modeling tasks.","PeriodicalId":434632,"journal":{"name":"XX Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI 2007)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121934784","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: 9
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