Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945352
Jaume Rigau, M. Feixas, M. Sbert, P. Bekaert
In this paper, we present view-dependent information theory quality measures for pixel sampling and scene discretization in flatland. The measures are based on a definition for the mutual information of a line, and have a purely geometrical basis. Several algorithms exploiting them are presented and compare well with an existing one based on depth differences.
{"title":"View-dependent information theory quality measures for pixel sampling and scene discretization in flatland","authors":"Jaume Rigau, M. Feixas, M. Sbert, P. Bekaert","doi":"10.1109/SCCG.2001.945352","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945352","url":null,"abstract":"In this paper, we present view-dependent information theory quality measures for pixel sampling and scene discretization in flatland. The measures are based on a definition for the mutual information of a line, and have a purely geometrical basis. Several algorithms exploiting them are presented and compare well with an existing one based on depth differences.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114733106","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}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945344
S. Battiato, G. Gallo, G. Impoco, F. Stanco
The efficiency of lossless compression algorithms for fixed palette images (also called indexed images) changes if a different indexing scheme is adopted. Indeed, these algorithms adopt a differential-predictive approach of some sort: if the spatial distribution of the indexes over the image is smooth, greater compression ratios may be obtained. It hence becomes relevant to find an indexing scheme that realizes such a smooth distribution. This seems to be a hard problem, and only approximate answers can be provided if a realistic run-time has to be achieved. In this paper, we propose a new indexing scheme, based on an approximate algorithm that maximizes the cost of a Hamiltonian path in a weighted graph. The proposed technique compares favourably with the algorithm proposed by W. Zeng et al. (2000). The computational complexity of the two algorithms is compared and experimental tests that show that relative compression rates are reported.
{"title":"A colour reindexing algorithm for lossless compression of digital images","authors":"S. Battiato, G. Gallo, G. Impoco, F. Stanco","doi":"10.1109/SCCG.2001.945344","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945344","url":null,"abstract":"The efficiency of lossless compression algorithms for fixed palette images (also called indexed images) changes if a different indexing scheme is adopted. Indeed, these algorithms adopt a differential-predictive approach of some sort: if the spatial distribution of the indexes over the image is smooth, greater compression ratios may be obtained. It hence becomes relevant to find an indexing scheme that realizes such a smooth distribution. This seems to be a hard problem, and only approximate answers can be provided if a realistic run-time has to be achieved. In this paper, we propose a new indexing scheme, based on an approximate algorithm that maximizes the cost of a Hamiltonian path in a weighted graph. The proposed technique compares favourably with the algorithm proposed by W. Zeng et al. (2000). The computational complexity of the two algorithms is compared and experimental tests that show that relative compression rates are reported.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114779257","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}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945336
R. Joan-Arinyo, Antoni Soto-Riera, S. Vila-Marta, Josep Vilaplana-Pasto
We study the domain of two constructive geometric constraint solving techniques. Both deal with constraints represented by a geometric constraint graph. The first technique analyses the graph bottom-up, from the edges to the whole graph. The second technique analyses the graph top-down, from the whole graph to the individual edges. We describe these techniques using abstract reduction systems which simplifies the study of their properties. We present an abstract description of the domain of each technique. Finally, we show that both techniques have the same domain, that is, they solve the same kind of problems defined by geometric constraints.
{"title":"On the domain of constructive geometric constraint solving techniques","authors":"R. Joan-Arinyo, Antoni Soto-Riera, S. Vila-Marta, Josep Vilaplana-Pasto","doi":"10.1109/SCCG.2001.945336","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945336","url":null,"abstract":"We study the domain of two constructive geometric constraint solving techniques. Both deal with constraints represented by a geometric constraint graph. The first technique analyses the graph bottom-up, from the edges to the whole graph. The second technique analyses the graph top-down, from the whole graph to the individual edges. We describe these techniques using abstract reduction systems which simplifies the study of their properties. We present an abstract description of the domain of each technique. Finally, we show that both techniques have the same domain, that is, they solve the same kind of problems defined by geometric constraints.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134194881","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}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945343
C. Zunino, B. Montrucchio, A. Sanna, C. Demartini
In computational fluid dynamics (CFD), visualization is a powerful instrument for research, training and development. It has been used for data evaluation and for qualitative comparison to flow visualization originating from experiments. The design and implementation of distributed visualization systems involve a set of issues mainly concerning performance, reliability and ease of developing and upgrading the system. In this paper, we consider a new technology called Jini used for designing distributed computing environments; we point out advantages and drawbacks related to the employment of Jini in the distributed visualization of vector fields based on particle tracing.
{"title":"A distributed visualization environment for scientific visualization based on Jini technology","authors":"C. Zunino, B. Montrucchio, A. Sanna, C. Demartini","doi":"10.1109/SCCG.2001.945343","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945343","url":null,"abstract":"In computational fluid dynamics (CFD), visualization is a powerful instrument for research, training and development. It has been used for data evaluation and for qualitative comparison to flow visualization originating from experiments. The design and implementation of distributed visualization systems involve a set of issues mainly concerning performance, reliability and ease of developing and upgrading the system. In this paper, we consider a new technology called Jini used for designing distributed computing environments; we point out advantages and drawbacks related to the employment of Jini in the distributed visualization of vector fields based on particle tracing.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131563690","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}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945339
M. Neamtu
A construction of bivariate splines is described, based on a new concept of higher degree Delaunay configurations. The crux of this construction is that knot-sets for simplex B-splines are selected by considering groups of "nearby" knots. The new approach gives rise to a natural generalization of univariate splines in that the linear span of this collection of B-splines forms a space which is analogous to the classical univariate splines. This new spline space depends uniquely and in a local way on the prescribed knot locations, and there is no need to use auxiliary or perturbed knots as in some earlier constructions.
{"title":"Bivariate simplex B-splines: a new paradigm","authors":"M. Neamtu","doi":"10.1109/SCCG.2001.945339","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945339","url":null,"abstract":"A construction of bivariate splines is described, based on a new concept of higher degree Delaunay configurations. The crux of this construction is that knot-sets for simplex B-splines are selected by considering groups of \"nearby\" knots. The new approach gives rise to a natural generalization of univariate splines in that the linear span of this collection of B-splines forms a space which is analogous to the classical univariate splines. This new spline space depends uniquely and in a local way on the prescribed knot locations, and there is no need to use auxiliary or perturbed knots as in some earlier constructions.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128157765","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}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945351
P. Gonzalez, Isidro Verdú
Presents an algorithm which aims at reducing the execution time and memory requirements of the synthesis of plants which are generated by a D0L system (deterministic context-free Lindenmayer system) and rendered by ray tracing. We propose a new method that carries out an intersection test directly with the production obtained by a D0L system, and thus attain considerable size reduction in the database. To reduce the computation time, the method works with a bounding volume hierarchy and adapts to the available memory by storing the hierarchy as far as a certain depth. Both the graphical primitives and those bounding volumes that have not been stored in memory are calculated at tracing time when they are required. We have compared our intersection test with a classical intersection test and with the commercial ray tracer PovRay, obtaining important reductions in computation time and memory in both cases.
{"title":"An efficient technique for ray tracing of a D0L-system","authors":"P. Gonzalez, Isidro Verdú","doi":"10.1109/SCCG.2001.945351","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945351","url":null,"abstract":"Presents an algorithm which aims at reducing the execution time and memory requirements of the synthesis of plants which are generated by a D0L system (deterministic context-free Lindenmayer system) and rendered by ray tracing. We propose a new method that carries out an intersection test directly with the production obtained by a D0L system, and thus attain considerable size reduction in the database. To reduce the computation time, the method works with a bounding volume hierarchy and adapts to the available memory by storing the hierarchy as far as a certain depth. Both the graphical primitives and those bounding volumes that have not been stored in memory are calculated at tracing time when they are required. We have compared our intersection test with a classical intersection test and with the commercial ray tracer PovRay, obtaining important reductions in computation time and memory in both cases.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"436 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132558959","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}
Pub Date : 2001-04-25DOI: 10.1109/SCCG.2001.945341
Bedrich Benes, Rafael Forsbach
New data structure for visual simulation of 3D terrains is introduced. The representation is inspired by real geological measurements and presents good trade-off between commonly used inexpensive, but inaccurate, height fields and memory demanding voxel representation. The representation is based on horizontal stratified layers consisting of one material. The layers are captured in certain positions of the landscape. This representation is then discretized into a 2D array. We demonstrate that the classical algorithm simulating thermal erosion (F.K. Musgrave, 1989), can run on this representation and we can even simulate some new properties. The simulation has been done on artificial data as well as on real data from Mars.
{"title":"Layered data representation for visual simulation of terrain erosion","authors":"Bedrich Benes, Rafael Forsbach","doi":"10.1109/SCCG.2001.945341","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945341","url":null,"abstract":"New data structure for visual simulation of 3D terrains is introduced. The representation is inspired by real geological measurements and presents good trade-off between commonly used inexpensive, but inaccurate, height fields and memory demanding voxel representation. The representation is based on horizontal stratified layers consisting of one material. The layers are captured in certain positions of the landscape. This representation is then discretized into a 2D array. We demonstrate that the classical algorithm simulating thermal erosion (F.K. Musgrave, 1989), can run on this representation and we can even simulate some new properties. The simulation has been done on artificial data as well as on real data from Mars.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130617916","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}
Pub Date : 1900-01-01DOI: 10.1109/SCCG.2001.945335
K. Buhler
A critical discussion of existing applications of reliable methods in computer graphics and the fact that one of the key applications of reliable arithmetics in computer graphics is its use for range analysis provokes a reconsideration of existing ideas of bounding volumes. A novel kind of parametrized bounding volume for parametric surfaces is proposed that informs about the location of each surface point and the corresponding parameters, as well as the location of the surface . Taylor models and the intrinsic structure of affine arithmetic are used to realize the discussed concepts in the form of linear interval estimations (LIEs). The sophisticated use of reliable methods and the characteristics of LIEs allow an effective intersection test for LIEs that also gives information about those parts of the parameter domains possibly affected by an intersection of the enclosed surface patches. A novel subdivision algorithm for the intersection of two parametric surfaces with remarkable experimental results is presented as a possible application for LIEs.
{"title":"Taylor models and affine arithmetics-towards a more sophisticated use of reliable methods in computer graphics","authors":"K. Buhler","doi":"10.1109/SCCG.2001.945335","DOIUrl":"https://doi.org/10.1109/SCCG.2001.945335","url":null,"abstract":"A critical discussion of existing applications of reliable methods in computer graphics and the fact that one of the key applications of reliable arithmetics in computer graphics is its use for range analysis provokes a reconsideration of existing ideas of bounding volumes. A novel kind of parametrized bounding volume for parametric surfaces is proposed that informs about the location of each surface point and the corresponding parameters, as well as the location of the surface . Taylor models and the intrinsic structure of affine arithmetic are used to realize the discussed concepts in the form of linear interval estimations (LIEs). The sophisticated use of reliable methods and the characteristics of LIEs allow an effective intersection test for LIEs that also gives information about those parts of the parameter domains possibly affected by an intersection of the enclosed surface patches. A novel subdivision algorithm for the intersection of two parametric surfaces with remarkable experimental results is presented as a possible application for LIEs.","PeriodicalId":331436,"journal":{"name":"Proceedings Spring Conference on Computer Graphics","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123033818","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}
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