Pub Date : 2001-10-16DOI: 10.1109/PCCGA.2001.962863
B. Oh, Chang-Hun Kim
The paper presents a progressive algorithm for reconstructing a 3D structure from a given 2D sketch drawing (edge-vertex graph without hidden line removal) according to the user's sketch order. While previous methods reconstruct a 3D structure at once, the proposed method progressively calculate a 3D structure by optimizing the coordinates of vertices of an object according to the sketch order. The progressive method reconstructs the most plausible 3D object quickly by applying 3D constraints that are derived from the relationship between the object and the sketch drawing in the optimization process. Furthermore, it allows the user to change viewpoint during sketching, and also minimize distortion of an object by refining inaccurate sketch drawings. The progressive reconstruction algorithm is discussed, and examples from a working implementation are given.
{"title":"Progressive 3D reconstruction from a sketch drawing","authors":"B. Oh, Chang-Hun Kim","doi":"10.1109/PCCGA.2001.962863","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962863","url":null,"abstract":"The paper presents a progressive algorithm for reconstructing a 3D structure from a given 2D sketch drawing (edge-vertex graph without hidden line removal) according to the user's sketch order. While previous methods reconstruct a 3D structure at once, the proposed method progressively calculate a 3D structure by optimizing the coordinates of vertices of an object according to the sketch order. The progressive method reconstructs the most plausible 3D object quickly by applying 3D constraints that are derived from the relationship between the object and the sketch drawing in the optimization process. Furthermore, it allows the user to change viewpoint during sketching, and also minimize distortion of an object by refining inaccurate sketch drawings. The progressive reconstruction algorithm is discussed, and examples from a working implementation are given.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121211119","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962886
Yasuhiro Suzuki, K. Miura, Ichiro Tanaka, H. Masuda
Streamline modeling is a design methodology of fair free form surfaces where the tangent vectors are specified/manipulated to generate/deform them instead of the control points of the traditional surface representations (K.T. Miura et al., 1998). Creations and deformations of complex 3D free form shapes generally require a large amount of labour and cost. Therefore, the authors propose a novel modeling technique based on of fluid flow dynamics in order to create and deform high-quality surfaces more intuitively with a smaller number of parameters based on the streamline modeling. We construct a flow field based on the potential flow, then calculate tangent vectors in the flow field that are required for the streamline modeling. Streamlines are generated by numerically integrating the tangent vectors, then the surface is represented as a set of streamlines. The deformation of the surface is performed by changing of the flow field. We have developed a prototype design system using the new modeling technique.
{"title":"Streamline modeling based on potential flow","authors":"Yasuhiro Suzuki, K. Miura, Ichiro Tanaka, H. Masuda","doi":"10.1109/PCCGA.2001.962886","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962886","url":null,"abstract":"Streamline modeling is a design methodology of fair free form surfaces where the tangent vectors are specified/manipulated to generate/deform them instead of the control points of the traditional surface representations (K.T. Miura et al., 1998). Creations and deformations of complex 3D free form shapes generally require a large amount of labour and cost. Therefore, the authors propose a novel modeling technique based on of fluid flow dynamics in order to create and deform high-quality surfaces more intuitively with a smaller number of parameters based on the streamline modeling. We construct a flow field based on the potential flow, then calculate tangent vectors in the flow field that are required for the streamline modeling. Streamlines are generated by numerically integrating the tangent vectors, then the surface is represented as a set of streamlines. The deformation of the surface is performed by changing of the flow field. We have developed a prototype design system using the new modeling technique.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125192261","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962862
J. Barhak, A. Fischer
Reverse engineering is an important process in CAD systems today. Yet several open problems lead to a bottleneck in the reverse engineering process. First, because the topology of the object to be reconstructed is unknown, point connectivity relations are undefined. Second, the fitted surface must satisfy global and local shape preservation criteria that are undefined explicitly. In reverse engineering, object reconstruction is based both on parameterization and on fitting. Nevertheless, the above problems are influenced mainly by parameterization. In order to overcome the above problems, the paper proposes a neural network, Self Organizing Map (SOM) method, for creating a 3D parametric grid. The main advantage of the proposed SOM method is that it detects both the orientation of the grid and the position of the sub-boundaries. The neural network grid converges to the sampled shape through an adaptive learning process. The SOM method is applied directly on 3D sampled data and avoids the projection anomalies common to other methods. The paper also presents boundary correction and growing grid extensions to the SOM method. In the surface fitting stage, an RSEC (Random Surface Error Correction) fitting method based on the SOM method was developed and implemented.
{"title":"Adaptive reconstruction of freeform objects with 3D SOM neural network grids","authors":"J. Barhak, A. Fischer","doi":"10.1109/PCCGA.2001.962862","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962862","url":null,"abstract":"Reverse engineering is an important process in CAD systems today. Yet several open problems lead to a bottleneck in the reverse engineering process. First, because the topology of the object to be reconstructed is unknown, point connectivity relations are undefined. Second, the fitted surface must satisfy global and local shape preservation criteria that are undefined explicitly. In reverse engineering, object reconstruction is based both on parameterization and on fitting. Nevertheless, the above problems are influenced mainly by parameterization. In order to overcome the above problems, the paper proposes a neural network, Self Organizing Map (SOM) method, for creating a 3D parametric grid. The main advantage of the proposed SOM method is that it detects both the orientation of the grid and the position of the sub-boundaries. The neural network grid converges to the sampled shape through an adaptive learning process. The SOM method is applied directly on 3D sampled data and avoids the projection anomalies common to other methods. The paper also presents boundary correction and growing grid extensions to the SOM method. In the surface fitting stage, an RSEC (Random Surface Error Correction) fitting method based on the SOM method was developed and implemented.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116445055","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962896
Y. Dobashi, Tsuyoshi Yamamoto, T. Nishita
A number of methods have been developed for creating realistic images of natural scenes. Their applications include flight simulators, the visual assessment of outdoor scenery, etc. Previously, many of these methods have focused on creating images under clear or slightly cloudy days. Simulations under bad weather conditions, however, are one of the important issues for realism. Lightning is one of the essential elements for these types of simulations. The paper proposes an efficient method for creating realistic images of scenes including lightning. Our method can create photo-realistic images by taking into account the scattering effects due to clouds and atmospheric particles illuminated by lightning. Moreover, graphics hardware is utilized to accelerate the image generation. The usefulness of our method is demonstrated by creating images of outdoor scenes that include lightning.
{"title":"Efficient rendering of lightning taking into account scattering effects due to clouds and atmospheric particles","authors":"Y. Dobashi, Tsuyoshi Yamamoto, T. Nishita","doi":"10.1109/PCCGA.2001.962896","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962896","url":null,"abstract":"A number of methods have been developed for creating realistic images of natural scenes. Their applications include flight simulators, the visual assessment of outdoor scenery, etc. Previously, many of these methods have focused on creating images under clear or slightly cloudy days. Simulations under bad weather conditions, however, are one of the important issues for realism. Lightning is one of the essential elements for these types of simulations. The paper proposes an efficient method for creating realistic images of scenes including lightning. Our method can create photo-realistic images by taking into account the scattering effects due to clouds and atmospheric particles illuminated by lightning. Moreover, graphics hardware is utilized to accelerate the image generation. The usefulness of our method is demonstrated by creating images of outdoor scenes that include lightning.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127902717","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962856
Vitaly Surazhsky, C. Gotsman
A "stick figure" is a connected straight-line plane graph, sometimes called a "skeleton". Compatible stick figures are those with the same topological structure. We present a method for naturally morphing between two compatible stick figures in a manner that preserves compatibility throughout the morph. In particular, this guarantees that the intermediate shapes are also stick figures (e.g. they do not self-intersect). Our method generalizes existing algorithms for morphing compatible planar polygons using Steiner vertices, and improves the complexity of those algorithms by reducing the number of Steiner vertices used.
{"title":"Morphing stick figures using optimized compatible triangulations","authors":"Vitaly Surazhsky, C. Gotsman","doi":"10.1109/PCCGA.2001.962856","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962856","url":null,"abstract":"A \"stick figure\" is a connected straight-line plane graph, sometimes called a \"skeleton\". Compatible stick figures are those with the same topological structure. We present a method for naturally morphing between two compatible stick figures in a manner that preserves compatibility throughout the morph. In particular, this guarantees that the intermediate shapes are also stick figures (e.g. they do not self-intersect). Our method generalizes existing algorithms for morphing compatible planar polygons using Steiner vertices, and improves the complexity of those algorithms by reducing the number of Steiner vertices used.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130254458","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962879
Ming-Dar Tsai, Shyan-Bin Jou, M. Hsieh
Existing volumetric representations model a non-thickness surface using voxels, and thus cannot accurately manipulate topology changes in the interactions between surfaces and solids. The study describes a volume representation in which face flags and distance-levels on each voxel represent surface topology and geometry, and an object flag identifies solids. Also presented is a set of algorithms that voxelize solids and surfaces, check the closures of the interactions among the volumetric surfaces and solids and manipulate various operations on the solids. A surgical example, in which the procedures involved in the complex interactions between cutting surfaces and anatomic structures and various geometric and topologic manipulations on the structures, are simulated to demonstrate that these novel volume representation techniques and algorithms are feasible in manipulating the interactions between surfaces and solids in a volume.
{"title":"Accurate surface voxelization for manipulating volumetric surfaces and solids with application in simulating musculoskeletal surgery","authors":"Ming-Dar Tsai, Shyan-Bin Jou, M. Hsieh","doi":"10.1109/PCCGA.2001.962879","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962879","url":null,"abstract":"Existing volumetric representations model a non-thickness surface using voxels, and thus cannot accurately manipulate topology changes in the interactions between surfaces and solids. The study describes a volume representation in which face flags and distance-levels on each voxel represent surface topology and geometry, and an object flag identifies solids. Also presented is a set of algorithms that voxelize solids and surfaces, check the closures of the interactions among the volumetric surfaces and solids and manipulate various operations on the solids. A surgical example, in which the procedures involved in the complex interactions between cutting surfaces and anatomic structures and various geometric and topologic manipulations on the structures, are simulated to demonstrate that these novel volume representation techniques and algorithms are feasible in manipulating the interactions between surfaces and solids in a volume.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117187102","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962893
R. Miyazaki, S. Yoshida, T. Nishita, Y. Dobashi
The simulation of natural phenomena such as clouds, smoke, fire and water is one of the most important research areas in computer graphics. In particular, clouds play an important role in creating images of outdoor scenes. The proposed method is based on the physical simulation of atmospheric fluid dynamics which characterizes the shape of clouds. To take account of the dynamics, we used a method called the coupled map lattice (CML). CML is an extended method of cellular automaton and is computationally inexpensive. The proposed method can create various types of clouds and can also realize the animation of these clouds. Moreover, we have developed an interactive system for modeling various types of clouds.
{"title":"A method for modeling clouds based on atmospheric fluid dynamics","authors":"R. Miyazaki, S. Yoshida, T. Nishita, Y. Dobashi","doi":"10.1109/PCCGA.2001.962893","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962893","url":null,"abstract":"The simulation of natural phenomena such as clouds, smoke, fire and water is one of the most important research areas in computer graphics. In particular, clouds play an important role in creating images of outdoor scenes. The proposed method is based on the physical simulation of atmospheric fluid dynamics which characterizes the shape of clouds. To take account of the dynamics, we used a method called the coupled map lattice (CML). CML is an extended method of cellular automaton and is computationally inexpensive. The proposed method can create various types of clouds and can also realize the animation of these clouds. Moreover, we have developed an interactive system for modeling various types of clouds.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117324171","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962876
C. Bajaj, Sanghun Park, I. Ihm
When interactive real-time applications are developed with very large volume data, the use of lossy compression is often inevitable. Lossy compression schemes generally encode data without consideration of the purpose of visualization that is actually performed, which often results in inefficient compression. In this paper, we present a new method for classifying voxels according to their importance in visualization, and assigning appropriate weights to them. The associated weight information can be combined with lossy compression schemes to reduce the visual degradation of reconstructed images, resulting in higher compression rates and visual fidelity. Test results demonstrate that the proposed technique improves both the amount of compression and the quality of visualization significantly.
{"title":"Visualization-specific compression of large volume data","authors":"C. Bajaj, Sanghun Park, I. Ihm","doi":"10.1109/PCCGA.2001.962876","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962876","url":null,"abstract":"When interactive real-time applications are developed with very large volume data, the use of lossy compression is often inevitable. Lossy compression schemes generally encode data without consideration of the purpose of visualization that is actually performed, which often results in inefficient compression. In this paper, we present a new method for classifying voxels according to their importance in visualization, and assigning appropriate weights to them. The associated weight information can be combined with lossy compression schemes to reduce the visual degradation of reconstructed images, resulting in higher compression rates and visual fidelity. Test results demonstrate that the proposed technique improves both the amount of compression and the quality of visualization significantly.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123918957","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962855
Manuel M. Oliveira
Most rendering engines subdivide arbitrary polygons into a collection of triangles, which are then rendered independently of each other. This procedure can introduce severe artifacts when rendering texture-mapped quadrilaterals. These errors result from a fundamental limitation: the impossibility of performing general projective mappings using only the information available at the vertices of a single triangle. Texture mapping involving arbitrary quadrilaterals has practical importance in applications that use real images as textures, such as in image-based modeling and rendering. The paper presents an efficient adaptive-subdivision solution to the problem, which, due to its simplicity, can be easily incorporated into graphics APIs.
{"title":"Correcting texture mapping errors introduced by graphics hardware","authors":"Manuel M. Oliveira","doi":"10.1109/PCCGA.2001.962855","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962855","url":null,"abstract":"Most rendering engines subdivide arbitrary polygons into a collection of triangles, which are then rendered independently of each other. This procedure can introduce severe artifacts when rendering texture-mapped quadrilaterals. These errors result from a fundamental limitation: the impossibility of performing general projective mappings using only the information available at the vertices of a single triangle. Texture mapping involving arbitrary quadrilaterals has practical importance in applications that use real images as textures, such as in image-based modeling and rendering. The paper presents an efficient adaptive-subdivision solution to the problem, which, due to its simplicity, can be easily incorporated into graphics APIs.","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132811507","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 : 2001-10-16DOI: 10.1109/PCCGA.2001.962875
M. Gross
Within the history of computer graphics a plenitude of sophisticated surface representations and graphics primitives have been devised, including splines, implicit surfaces, or hierarchical approaches. All of these methods aim at facilitating the creation, processing and display of graphics models with increasingly complex shape or surface detail. In spite of the sophistication of these methods the triangle has survived over decades as the major graphics primitive meeting a right balance between descriptive power and computational effort. As a consequence, today’s consumer graphics hardware is mostly tailored to high performance triangle processing. In addition, an upcoming repertoire of powerful geometric processing methods seems to foster the concept of triangle meshes for graphics modeling. In recent years, the emergence of affordable 3D scanning devices along with the demand for ever more geometric detail and rich organic shapes has created the need to process and render very large point sampled models efficiently. At data sizes where triangle based methods approach their limits point representations are receiving a growing attention. Unlike triangles, points have largely been neglected as a graphics primitive. Although being included in many APIs, it is only recently that point samples experience a renaissance in computer graphics. Conceptually, points provide a discretization of geometry without explicit storage of topology. Thus, point samples reduce the representation to the essentials needed for rendering and enable us to generate highly optimized object representations. Although the loss of topology poses great challenges for graphics processing, the latest generation of algorithms features high performance rendering, point/pixel shading, anisotropic texture mapping, and advanced signal processing of point sampled geometry. In this talk, I will introduce point samples as a versatile graphics primitive and present concepts for the acquisition, processing and rendering of large point sets. The first part of the talk discusses low-cost scanning devices and algorithms being used to reconstruct 3D point clouds from video image sequences. Powerful PC clusters allow for the real-time computation of the underlying image processing algorithms. Such concepts have been used within the ETH blue-c1 collaborative virtual environment. After the acquisition of raw point samples sophisticated postprocessing techniques are required to clean, denoise, enhance, or smooth the data. The second part of this talk presents our latest concepts for generalizing Fourier transforms to point sampled geometry. The method constitutes a partitioning of the point set and computes a local spectral decomposition for each patch using the FFT. The notion of frequency gives us access to a rich repertoire of signal processing methods including lowpass or highpass filtering, spectral estimation and resampling. The third part of my talk is dedicated to the concepts we developed
{"title":"Processing and rendering of point sampled geometry","authors":"M. Gross","doi":"10.1109/PCCGA.2001.962875","DOIUrl":"https://doi.org/10.1109/PCCGA.2001.962875","url":null,"abstract":"Within the history of computer graphics a plenitude of sophisticated surface representations and graphics primitives have been devised, including splines, implicit surfaces, or hierarchical approaches. All of these methods aim at facilitating the creation, processing and display of graphics models with increasingly complex shape or surface detail. In spite of the sophistication of these methods the triangle has survived over decades as the major graphics primitive meeting a right balance between descriptive power and computational effort. As a consequence, today’s consumer graphics hardware is mostly tailored to high performance triangle processing. In addition, an upcoming repertoire of powerful geometric processing methods seems to foster the concept of triangle meshes for graphics modeling. In recent years, the emergence of affordable 3D scanning devices along with the demand for ever more geometric detail and rich organic shapes has created the need to process and render very large point sampled models efficiently. At data sizes where triangle based methods approach their limits point representations are receiving a growing attention. Unlike triangles, points have largely been neglected as a graphics primitive. Although being included in many APIs, it is only recently that point samples experience a renaissance in computer graphics. Conceptually, points provide a discretization of geometry without explicit storage of topology. Thus, point samples reduce the representation to the essentials needed for rendering and enable us to generate highly optimized object representations. Although the loss of topology poses great challenges for graphics processing, the latest generation of algorithms features high performance rendering, point/pixel shading, anisotropic texture mapping, and advanced signal processing of point sampled geometry. In this talk, I will introduce point samples as a versatile graphics primitive and present concepts for the acquisition, processing and rendering of large point sets. The first part of the talk discusses low-cost scanning devices and algorithms being used to reconstruct 3D point clouds from video image sequences. Powerful PC clusters allow for the real-time computation of the underlying image processing algorithms. Such concepts have been used within the ETH blue-c1 collaborative virtual environment. After the acquisition of raw point samples sophisticated postprocessing techniques are required to clean, denoise, enhance, or smooth the data. The second part of this talk presents our latest concepts for generalizing Fourier transforms to point sampled geometry. The method constitutes a partitioning of the point set and computes a local spectral decomposition for each patch using the FFT. The notion of frequency gives us access to a rich repertoire of signal processing methods including lowpass or highpass filtering, spectral estimation and resampling. The third part of my talk is dedicated to the concepts we developed","PeriodicalId":387699,"journal":{"name":"Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123075648","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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