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2006 19th Brazilian Symposium on Computer Graphics and Image Processing最新文献

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Free head motion eye gaze tracking using a single camera and multiple light sources 使用单个摄像头和多个光源的自由头部运动眼睛注视跟踪
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.21
F. Coutinho, C. Morimoto
{"title":"Free head motion eye gaze tracking using a single camera and multiple light sources","authors":"F. Coutinho, C. Morimoto","doi":"10.1109/SIBGRAPI.2006.21","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.21","url":null,"abstract":"One of the main limitations of current remote eye gaze tracking (REGT) techniques is that the user's head must remain within a very limited area in front of the monitor screen. In this paper, we present a free head motion REGT technique. By projecting a known rectangular pattern of lights, the technique estimates the gaze position relative to this rectangle using an invariant property of projective geometry. We carry extensive analysis of similar methods using an eye model to compare their accuracy. Based on these results, we propose a new estimation procedure that compensates the angular difference between the eye visual axis and optical axis. We have developed a real time (30 fps) prototype using a single camera and 5 light sources to generate the light pattern. Experimental results shows that the accuracy of the system is about 1deg of visual angle","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"32 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114013957","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: 71
Tree-Pruning: A New Algorithm and Its Comparative Analysis with the Watershed Transform for Automatic Image Segmentation 树剪枝:一种新的图像自动分割算法及其与分水岭变换的对比分析
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.44
P. A. Miranda, F. Bergo, Leonardo M. Rocha, A. Falcão
{"title":"Tree-Pruning: A New Algorithm and Its Comparative Analysis with the Watershed Transform for Automatic Image Segmentation","authors":"P. A. Miranda, F. Bergo, Leonardo M. Rocha, A. Falcão","doi":"10.1109/SIBGRAPI.2006.44","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.44","url":null,"abstract":"Image segmentation using tree pruning (TP) and watershed (WS) has been presented in the framework of the image forest transform (IFT) - a method to reduce image processing problems related to connectivity into an optimum-path forest problem in a graph. Given that both algorithms use the IFT with similar parameters, they usually produce similar segmentation results. However, they rely on different properties of the IFT which make TP more robust than WS for automatic segmentation tasks. We propose and demonstrate an important improvement in the TP algorithm, clarify the differences between TP and WS, and provide their comparative analysis from the theoretical and practical points of view. The experiments involve automatic segmentation of license plates in a database with 990 images","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123660030","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: 8
Curvature-driven modeling and rendering of point-based surfaces 基于点的曲面的曲率驱动建模和渲染
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.9
J. P. Gois, Eduardo Tejada, Tiago Etiene, L. G. Nonato, A. C. Filho, T. Ertl
{"title":"Curvature-driven modeling and rendering of point-based surfaces","authors":"J. P. Gois, Eduardo Tejada, Tiago Etiene, L. G. Nonato, A. C. Filho, T. Ertl","doi":"10.1109/SIBGRAPI.2006.9","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.9","url":null,"abstract":"In this work we address the problem of computing point-based surface approximations from point clouds. Our approach is based on recently presented methods that define the approximated surface as the set of stationary points for an operator that projects points in the space onto the surface. We present a novel projection operator that differs from the defined in previous work in that it uses principal curvatures and directions approximation and an anisotropic diffusion equation to ensure an accurate approximation to the surface. We show how to estimate the principal curvatures and directions for point clouds and discuss the usefulness of the curvature information in the context of point-based surface modeling and rendering","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116567471","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: 10
Single Triangle Strip and Loop on Manifolds with Boundaries 带边界流形上的单三角带和环
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.41
Pablo Diaz-Gutierrez, D. Eppstein, M. Gopi
{"title":"Single Triangle Strip and Loop on Manifolds with Boundaries","authors":"Pablo Diaz-Gutierrez, D. Eppstein, M. Gopi","doi":"10.1109/SIBGRAPI.2006.41","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.41","url":null,"abstract":"The single triangle-strip loop generation algorithm on a triangulated two-manifold presented by Gopi and Eppstein (2004) is based on the guaranteed existence of a perfect matching in its dual graph. However, such a perfect matching is not guaranteed in the dual graph of triangulated manifolds with boundaries. In this paper, we present algorithms that suitably modify the results of the dual graph matching to generate a single strip loop on manifolds with boundaries. Further, the algorithm presented by Gopi and Eppstein (2004) can produce only strip loops, but not linear strips. We present an algorithm that does topological surgery to construct linear strips, with user-specified start and end triangles, on manifolds with or without boundaries. The main contributions of this paper include graph algorithms to handle unmatched triangles, reduction of the number of Steiner vertices introduced to create strip loops, and finally a novel method to generate single linear strips with arbitrary start and end positions","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115580676","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: 4
Accuracy of Statistical Classification Strategies in Remote Sensing Imagery 遥感影像统计分类策略的准确性
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.4
A. Frery, S. Ferrero, O. Bustos
{"title":"Accuracy of Statistical Classification Strategies in Remote Sensing Imagery","authors":"A. Frery, S. Ferrero, O. Bustos","doi":"10.1109/SIBGRAPI.2006.4","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.4","url":null,"abstract":"We present the assessment of two classification procedures using a Monte Carlo experience and Landsat data. Classification performance is hard to assess with generality due to the huge number of variables involved. In this case, we consider the problem of classifying multispectral optical imagery with pointwise Gaussian maximum likelihood and contextual ICM (iterated conditional modes), with and without errors in the training stage. Using simulation the ground truth is known and, therefore, precise comparisons are possible. The contextual approach proved being superior than the pointwise one, at the expense of requiring more computational resources, with both real and simulated data. Quantitative and qualitative results are discussed","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"106 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120871198","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
Detection of Unusual Motion Using Computer Vision 利用计算机视觉检测异常运动
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.11
C. Jung, Julio C. S. Jacques Junior, J. Soldera, S. Musse
{"title":"Detection of Unusual Motion Using Computer Vision","authors":"C. Jung, Julio C. S. Jacques Junior, J. Soldera, S. Musse","doi":"10.1109/SIBGRAPI.2006.11","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.11","url":null,"abstract":"In this paper, we propose different criteria for detecting unusual motion in surveillance cameras. Initially, a certain environment is observed within a time interval, and captured trajectories are used as examples of usual trajectories. These trajectories are used to build a spatial occupancy map (SpOM, which is introduced in this paper) of the observed people, as well as main flow directions. In the test period, each new trajectory is classified as normal or unusual with respect to spatial occupancy and trajectory consistency. The spatial occupancy criterion considers the relation of space occupancy between the new tracked trajectory and the observed period. The trajectory consistency criterion considers the agreement of the new trajectory with the main flows extracted in the training period. Experimental results showed that these criteria can be used as an automatic pre-screening of suspect motion in surveillance applications","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115693324","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
Increasing statistical power in medical image analysis 提高医学图像分析的统计能力
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.27
A. Machado
{"title":"Increasing statistical power in medical image analysis","authors":"A. Machado","doi":"10.1109/SIBGRAPI.2006.27","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.27","url":null,"abstract":"In this paper, we present a novel method for estimating the effective number of independent variables in imaging applications that require multiple hypothesis testing. The method increases the statistical power of the results by refuting the assumption of independence among variables, while keeping the probability of false positives low. It is based on the spectral graph theory, in which the variables are seen as the vertices of a complete undirected graph and the correlation matrix as the adjacency matrix that weights its edges. By computing the eigenvalues of the correlation matrix, it is possible to obtain valuable information about the dependence levels among the variables of the problem. The method is compared to other available models and its effectiveness illustrated in a case study on the morphology of the human corpus callosum","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129820708","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
A Statistical Discriminant Model for Face Interpretation and Reconstruction 人脸判读与重建的统计判别模型
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.3
Edson C. Kitani, C. Thomaz, D. Gillies
{"title":"A Statistical Discriminant Model for Face Interpretation and Reconstruction","authors":"Edson C. Kitani, C. Thomaz, D. Gillies","doi":"10.1109/SIBGRAPI.2006.3","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.3","url":null,"abstract":"Multivariate statistical approaches have played an important role of recognising face images and characterizing their differences. In this paper, we introduce the idea of using a two-stage separating hyper-plane, here called statistical discriminant model (SDM), to interpret and reconstruct face images. Analogously to the well-known active appearance model proposed by Cootes et. al, SDM requires a previous alignment of all the images to a common template to minimise variations that are not necessarily related to differences between the faces. However, instead of using landmarks or annotations on the images, SDM is based on the idea of using PCA to reduce the dimensionality of the original images and a maximum uncertainty linear classifier (MLDA) to characterise the most discriminant changes between the groups of images. The experimental results based on frontal face images indicate that the SDM approach provides an intuitive interpretation of the differences between groups, reconstructing characteristics that are very subjective in human beings, such as beauty and happiness","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114681627","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: 16
Motion Segmentation using Mathematical Morphology 基于数学形态学的运动分割
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.29
A. C. Lara, R. Hirata
{"title":"Motion Segmentation using Mathematical Morphology","authors":"A. C. Lara, R. Hirata","doi":"10.1109/SIBGRAPI.2006.29","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.29","url":null,"abstract":"Motion segmentation is one of the first steps in image sequence applications. The problem has been extensively studied and approached in several ways but it remains a difficult task even for sequences acquired by stationary cameras. In this paper we propose a novel algorithm that is based on mathematical morphology. The algorithm is simple to be implemented, less subject to lighting changes and more robust to false positives. It has been tested in security cameras' image sequences showing promising results. Some algorithms from literature have been implemented and compared to the one described here","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131608425","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: 4
Exploratory visualization based on multidimensional transfer functions and star coordinates 基于多维传递函数和星形坐标的探索性可视化
2006 19th Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 2006-12-11 DOI: 10.1109/SIBGRAPI.2006.17
A. Bordignon, Rener Castro, H. Lopes, T. Lewiner, G. Tavares
{"title":"Exploratory visualization based on multidimensional transfer functions and star coordinates","authors":"A. Bordignon, Rener Castro, H. Lopes, T. Lewiner, G. Tavares","doi":"10.1109/SIBGRAPI.2006.17","DOIUrl":"https://doi.org/10.1109/SIBGRAPI.2006.17","url":null,"abstract":"Exploration and analysis of multivariate data play an important role in different domains. This work proposes a simple interface prototype that allows a human user to visually explore multivariate spatial objects, such as images, sequence of images or volume. It uses star coordinates as a widget to display the multivariate data on the computer 2D screen. The user then identifies a feature on this powerful coordinate system by mapping a selected feature region on that widget to a color and opacity. As a visual result, the feature is rendered on the object's space composing the use of this maps and the star coordinates projection. Some examples illustrate the potential of this interface","PeriodicalId":253871,"journal":{"name":"2006 19th Brazilian Symposium on Computer Graphics and Image Processing","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121989414","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: 13
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