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Proceedings X Brazilian Symposium on Computer Graphics and Image Processing最新文献

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Complementary filter banks for image compression 图像压缩的互补滤波器组
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625176
M. G. Almeida, L. Chaparro
{"title":"Complementary filter banks for image compression","authors":"M. G. Almeida, L. Chaparro","doi":"10.1109/SIGRA.1997.625176","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625176","url":null,"abstract":"In this paper we present a nonseparable complementary filter (CF) bank for image compression. We base our design of the filter bank on the two-dimensional (2D) multirate processing and on properties of complementary filters. Perfect reconstruction is guaranteed when the CF bank is implemented with quincunx sampling and filtering, but not otherwise. In all cases, however the analysis and synthesis are performed without aliasing. The CF bank can be related to wavelet theory, permitting us to derive scale and wavelet functions for different sampling and filters. Examples illustrating the performance of the CF banks in image data compression are given.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"348 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131107964","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
Analyzing a deformable model using differential geometry 用微分几何分析可变形模型
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625149
Paulo F De Santa, Clara Ramos, Shin-Ting Wu, Sueli I. R. Costa
{"title":"Analyzing a deformable model using differential geometry","authors":"Paulo F De Santa, Clara Ramos, Shin-Ting Wu, Sueli I. R. Costa","doi":"10.1109/SIGRA.1997.625149","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625149","url":null,"abstract":"The paper explores the use of elements of differential geometry to control the manipulation of the deformable model proposed by D. Terzopoulos et al. (1987) for animating deformable objects. Particularly, we are interested in the animation of deformable panels without stretching (area invariant), such as clothes and papers. Based on our analysis we could generate with a little effort several simulations compatible with our expectation.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115694193","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
Wavelet and entropy analysis combination to evaluate diffusion and correlation behaviours 结合小波和熵分析来评价扩散和相关行为
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625157
R. Chiou, M. Ferreira, C.T. Silva, A.E. Kaufman
{"title":"Wavelet and entropy analysis combination to evaluate diffusion and correlation behaviours","authors":"R. Chiou, M. Ferreira, C.T. Silva, A.E. Kaufman","doi":"10.1109/SIGRA.1997.625157","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625157","url":null,"abstract":"Diffusion and correlation effects are two principal phenomena which have been studied for years and several visualization techniques have been proposed to help scientists to understand them. The analysis of these phenomena will help to extract important information from data sets. To understand these problems we combine wavelet and entropy analysis to evaluate the evolution of these behaviours through scale and time. We present image case studies to show several different kinds of behaviours of these effects. Some of them are fallible cases and not reliable, as the images do not show the desired information. We calculate entropy of smooth and detail coefficient sets, generated by wavelet transform of these sample images in each scale, to obtain measures that allow us to evaluate these behaviours according to the organization complexity. These measures can provide an indication about the quality of the rendered images.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122270921","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
Similarity-based versus template matching-based methodologies for image alignment of polyhedral-like objects under noisy conditions 基于相似度与模板匹配的噪声条件下多面体图像对齐方法
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625165
L.deS. Coelho, M. Campos
{"title":"Similarity-based versus template matching-based methodologies for image alignment of polyhedral-like objects under noisy conditions","authors":"L.deS. Coelho, M. Campos","doi":"10.1109/SIGRA.1997.625165","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625165","url":null,"abstract":"The image alignment problem has as input a set of different images from a single object or several identical objects. One instance of the object in each image is misaligned relatively to the other in a given image, that is, the objects lie in different positions and orientations. Thus, the problem consists in finding the homogeneous planar transforms for each of those instances. The process is not simple in the case of noisy images. Nevertheless, it is possible to tackle some cases of the image alignment problem using template matching. This work describes two methodologies that were developed to align noisy images of protein quaternary structures obtained by Transmission Electron Microscopy (TEM). These structures can be geometrically described by regular prisms and polyhedra. One of the methods uses the traditional approach for this problem-exploring image similarities. The second one explores the geometric simplicity of the objects being imaged by using template matching in order to solve the problem. The results show that there are cases where the template matching method achieves higher precision and computational efficiency to align that kind of image when compared to traditional ones.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133525731","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
Tridimensional image reconstruction method based on the modified algebraic reconstruction technique and B-spline interpolation 基于改进代数重建技术和b样条插值的三维图像重建方法
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625156
G. C. Ribeiro, P. E. Cruvinel
{"title":"Tridimensional image reconstruction method based on the modified algebraic reconstruction technique and B-spline interpolation","authors":"G. C. Ribeiro, P. E. Cruvinel","doi":"10.1109/SIGRA.1997.625156","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625156","url":null,"abstract":"The article presents an algorithm for three dimensional reconstruction of tomographic images based on reconstructed two dimensional slices, using a modification of the technique of additive algebraic reconstruction and the spline function for interpolation of the intermediary planes in volumetric reconstruction. Development of the method was first destined to image reconstruction of the minitomographer at the National Center for Research and Instrumentation Development for Agriculture (CNPDIA) of the Brazilian Agricultural Research Company (EMBRAPA), which is dedicated to soil science. Evaluation of the results of the method was based on phantom images and soil samples, with 2 mm spatial resolution, 60 samples per projection, a 3 degree angle between projections, a 59.9 KeV Americium (/sup 241/Am) energy source, and a ten second time per projection sample. The results prove the usefulness and reliability of the method, which is also applicable to other tomographic systems.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114162262","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
Exact representation and operations on spherical maps 球面地图的精确表示和操作
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625152
M. Andrade, J. Stolfi
{"title":"Exact representation and operations on spherical maps","authors":"M. Andrade, J. Stolfi","doi":"10.1109/SIGRA.1997.625152","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625152","url":null,"abstract":"We develop exact algorithms for geometric operations on general circles and circular arcs on the sphere, using integer homogeneous coordinates. The algorithms include testing a point against a circle, computing the intersection of two circles, and ordering three arcs out of the same point. These operations allow robust manipulation of maps on the sphere, providing a reliable framework for GIS, robotics, and other geometric applications.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"482 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115878047","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: 0
Real-time rendering of photo-textured terrain height fields 实时渲染照片纹理地形高度场
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625143
L. Guedes, M. Gattass, P. Carvalho
{"title":"Real-time rendering of photo-textured terrain height fields","authors":"L. Guedes, M. Gattass, P. Carvalho","doi":"10.1109/SIGRA.1997.625143","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625143","url":null,"abstract":"Interactive tridimensional visualization of terrain models can be found in geographical information systems and computer games. Both applications share the need for high performance algorithms that are tailored to produce textured images in interactive time, say at least 5 frames per second. We propose and analyze the extension of a well known ray casting algorithm to the case where the view plane is not vertical. Three efficient algorithms are presented and compared. Experimental results are shown and conclusions are made.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121538031","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
Semi-automated dendrogram generation for neural shape analysis 用于神经形态分析的半自动树突图生成
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625164
R. Cesar, L. da Fontoura Costa
{"title":"Semi-automated dendrogram generation for neural shape analysis","authors":"R. Cesar, L. da Fontoura Costa","doi":"10.1109/SIGRA.1997.625164","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625164","url":null,"abstract":"This work introduces a new framework for shape characterization of neural cells by semi-automated generation of dendrograms, which are abstract structures describing different aspects associated to the branching structure of dendrites in neurons. Particularly, the dendrograms generated by the proposed method includes the length of each dendritic segment. The new method, which is based on multiscale curvature contour segmentation and syntactic shape analysis, is robust and greatly improves the tiresome task of dendrogram extraction, traditionally performed by human operators. Results corroborating the effectiveness of the technique are also presented.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125091571","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
An efficient filling algorithm for non-simple closed curves using the point containment paradigm 基于点包容范式的非简单封闭曲线的高效填充算法
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625138
A. Fabris, L. Silva, A. R. Forrest
{"title":"An efficient filling algorithm for non-simple closed curves using the point containment paradigm","authors":"A. Fabris, L. Silva, A. R. Forrest","doi":"10.1109/SIGRA.1997.625138","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625138","url":null,"abstract":"The point containment predicate which specifies if a point is part of a mathematically defined shape or not is one of the most basic notions in raster graphics. The paper presents a technique to counteract the main disadvantage of point containment algorithms: their quadratic time complexity with increasing resolution. The implemented algorithm handles complex geometries such as self-intersecting closed curves.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126340925","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
Building interactive animations using VRML and Java 使用VRML和Java构建交互式动画
Proceedings X Brazilian Symposium on Computer Graphics and Image Processing Pub Date : 1997-10-14 DOI: 10.1109/SIGRA.1997.625146
F.S. Tamiosso, A. Raposo, L. P. Magalhães, I. Ricarte
{"title":"Building interactive animations using VRML and Java","authors":"F.S. Tamiosso, A. Raposo, L. P. Magalhães, I. Ricarte","doi":"10.1109/SIGRA.1997.625146","DOIUrl":"https://doi.org/10.1109/SIGRA.1997.625146","url":null,"abstract":"The paper exploits the combination of VRML (Virtual Reality Modeling Language) and Java for the construction of highly interactive animations, whose behaviour is defined in real time by a user's actions. The animations are modeled in VRML, which allows the definition of a Java program to process and generate events that determine the behaviour of scene elements. An application for the generation of Java graphical interfaces was developed, aiming to establish the communication between the user and the VRML environment, sending parameters to the program that controls the animation.","PeriodicalId":445648,"journal":{"name":"Proceedings X Brazilian Symposium on Computer Graphics and Image Processing","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128304818","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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