International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa最新文献

{"title":"3-view impostors","authors":"A. Hardy, Johannes Venter","doi":"10.1145/1811158.1811180","DOIUrl":"https://doi.org/10.1145/1811158.1811180","url":null,"abstract":"In this article we present a new volumetric representation of objects which can be rendered in real-time on modern GPUs. We show how existing polygonal objects are transformed into a volumetric representation involving space carving and height fields. The performance of the rendering algorithm is determined by the screen space area of the volume, and is suitable as an impostor algorithm for objects sufficiently far from the viewer. These 3-view impostors are viewable from any angle and only need to be updated if the object is animated dynamically. 3-View impostors offer a number of advantages over competitive techniques, namely: regular sampling for several views, bounded texture usage, accelerated ray object surface intersection, and more robust handling of thin surfaces.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128152786","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}

{"title":"Progressive RBF interpolation","authors":"V. Skala","doi":"10.1145/1811158.1811161","DOIUrl":"https://doi.org/10.1145/1811158.1811161","url":null,"abstract":"Interpolation based on Radial Basis Functions (RBF) is very often used for scattered scalar data interpolation in n-dimensional space in general. RBFs are used for surface reconstruction of 3D objects, reconstruction of corrupted images etc. As there is no explicit order in data sets, computations are quite time consuming that leads to limitation of usability even for static data sets. Generally the complexity of computation of RBF interpolation for N points is of O(N3) or O(k N2), k is a number of iterations if iterative methods are used, which is prohibitive for real applications. The inverse matrix can also be computed by the Strassen algorithm based on matrix block notation with O(N2.807) complexity. Even worst situation occurs when interpolation has to be made over non-constant data sets, as the whole set of equations for determining RBFs has to be recomputed. This situation is typical for applications in which some points are becoming invalid and new points are acquired.\u0000 In this paper a new technique for incremental RBFs computation with complexity of O(N2) is presented. This technique enables efficient insertion of new points and removal of selected or invalid points. Due to the formulation it is possible to determine an error if one point is removed that leads to a possibility to determine the most important points from the precision of interpolation point of view and insert gradually new points, which will progressively decrease the error of interpolation using RBFs. The Progressive RBF Interpolation enables also fast interpolation on \"sliding window\" data due to insert/remove operations which will also lead to a faster rendering.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"476 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114110189","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}

{"title":"Minimum spanning trees for valley and ridge characterization in digital elevation maps","authors":"S. Bangay, David de Bruyn, Kevin R. Glass","doi":"10.1145/1811158.1811171","DOIUrl":"https://doi.org/10.1145/1811158.1811171","url":null,"abstract":"Texture synthesis employs neighbourhood matching to generate appropriate new content. Terrain synthesis has the added constraint that new content must be geographically plausible. The profile recognition and polygon breaking algorithm (PPA) [Chang et al. 1998] provides a robust mechanism for characterizing terrain as systems of valley and ridge lines in digital elevation maps. We exploit this to create a terrain characterization metric that is robust, efficient to compute and is sensitive to terrain properties.\u0000 Terrain regions are characterized as a minimum spanning tree derived from a graph created from the sample points of the elevation map which are encoded as weights in the edges of the graph. This formulation allows us to provide a single consistent feature definition that is sensitive to the pattern of ridges and valleys in the terrain Alternative formulations of these weights provide richer characteristic measures and we provide examples of alternate definitions based on curvature and contour measures.\u0000 We show that the measure is robust, with a significant portion derived directly from information local to the terrain sample. Global terrain characteristics introduce the issue of over- and under-connected valley/ridge lines when working with sub-regions. This is addressed by providing two graph construction strategies, which respectively provide an upper bound on connectivity as a single spanning tree, and a lower bound as a forest of trees.\u0000 Efficient minimum spanning tree algorithms are adapted to the context of terrain data and are shown to provide substantially better performance than previous PPA implementations. In particular, these are able to characterize valley and ridge behaviour at every point even in large elevation maps, providing a measure sensitive to terrain features at all scales.\u0000 The resulting graph based formulation provides an efficient and elegant algorithm for characterizing terrain features. The measure can be calculated efficiently, is robust under changes of neighbourhood position, size and resolution and the hybrid measure is sensitive to terrain features both locally and globally.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130516184","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}

{"title":"Dynamic load balancing of Lattice Boltzmann free-surface fluid animations","authors":"Ashley Reid, J. Gain, M. Kuttel","doi":"10.1145/1811158.1811174","DOIUrl":"https://doi.org/10.1145/1811158.1811174","url":null,"abstract":"We investigate the use of dynamic load balancing for more efficient parallel Lattice Boltzmann Method (LBM) Free Surface simulations. Our aim is to produce highly detailed fluid simulations with large grid sizes and without the use of optimisation techniques, such as adaptive grids, which may impact on simulation quality. We divide the problem into separate simulation chunks, which can then be distributed over multiple parallel processors. Due to the purely local grid interaction of the LBM, the algorithm parallelises well. However, the highly dynamic nature of typical scenes means that there is an unbalanced distribution of the fluid across the processors. Our proposed Dynamic Load Balancing strategy seeks to improve the efficiency of the simulation by measuring computation and communication times and adjusting the fluid distribution accordingly.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134382826","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}

{"title":"Out-of-core real-time visualization of massive 3D point clouds","authors":"R. Richter, J. Döllner","doi":"10.1145/1811158.1811178","DOIUrl":"https://doi.org/10.1145/1811158.1811178","url":null,"abstract":"This paper presents a point-based rendering approach to visualize massive sets of 3D points in real-time. In many disciplines such as architecture, engineering, and archeology LiDAR technology is used to capture sites and landscapes; the resulting massive 3D point clouds pose challenges for traditional storage, processing, and presentation techniques. The available hardware resources of CPU and GPU are limited, and the 3D point cloud data exceeds available memory size in general. Hence out-of-core strategies are required to overcome the limit of memory. We discuss concepts and implementations of rendering algorithms and interaction techniques that make out-of-core real-time visualization and exploration of massive 3D point clouds feasible. We demonstrate with our implementation real-time visualization of arbitrarily sized 3D point clouds with current PC hardware using a spatial data structure in combination with a point-based rendering algorithm. A rendering front is used to increase the performance taking into account user interaction as well as available hardware resources. Furthermore, we evaluate our approach, describe its characteristics, and report on applications.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116126181","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}

{"title":"Assessing a virtual baby feeding training system","authors":"A. Petrásová, G. Czanner, J. Happa, S. Czanner, D. Wolke, A. Chalmers","doi":"10.1145/1811158.1811165","DOIUrl":"https://doi.org/10.1145/1811158.1811165","url":null,"abstract":"Currently a considerable amount of time and resources are spent helping parents overcome issues related to feeding young infants. Designing interactive virtual feeding scenarios is a preventative means to reduce the adaptation process time for newly made parents, but also help new parents improve their approach to feeding their children. In this paper, we present a case study on using and assessing a virtual reality infant feeding application. Our results show that virtual training can increase the efficiency of feeding depending on the different behaviour of the child.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131162360","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}

{"title":"Programmable transitions for video stream editing","authors":"A. Hardy","doi":"10.1145/1503454.1503472","DOIUrl":"https://doi.org/10.1145/1503454.1503472","url":null,"abstract":"Video editing applications provide a facility to transition from one video stream to another, or to filter a video stream in some way. New transitions are usually developed using a custom API for the particular package. In this article we present a shading language for specifying transitions and filters on video streams. Video editing is performed by constructing a tree based on the transitions. The shading language is compiled to a virtual machine, but can still be executed efficiently. We provide several examples of transitions which have been successfully applied using our video stream editing software.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123651218","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}

{"title":"Using an implicit min/max KD-tree for doing efficient terrain line of sight calculations","authors":"B. Duvenhage","doi":"10.1145/1503454.1503469","DOIUrl":"https://doi.org/10.1145/1503454.1503469","url":null,"abstract":"The generation of accurate Line of Sight (LOS) visibility information consumes significant resources in large scale synthetic environments such as many-on-many serious games and battlefield simulators. Due to the importance of optimum utilisation of computing resources, a number of LOS algorithms are reported in the literature to either efficiently compute LOS information or reduce the impact of LOS queries on the run-time performance of synthetic environments. From the literature it is known that a k-dimensional tree (kd-tree) based raytracing approach, to calculating LOS information, is efficient.\u0000 A new implicit min/max kd-tree algorithm is discussed for evaluating LOS queries on large scale spherical terrain. In particular the value of low resolution boundary information, in quickly evaluating the LOS query, is emphasised. The min/max algorithm is empirically compared to other LOS approaches that have either implicitly or explicitly used kd-trees to optimise LOS query evaluation. The min/max algorithm is shown to have comparable performance to these existing LOS algorithms for flat earth, but improved performance when the application domain is extended to spherical earth. An average of a factor 3.0 performance increase is experienced over that of the existing implicit and explicit max kd-tree algorithms on spherical earth. This is achieved by combining the existing kd-tree algorithm with the classic smooth-earth LOS obscuration test and from there the min in min/max kd-tree.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"356 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123106115","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}

{"title":"Pick-by-Vision comes on age: evaluation of an augmented reality supported picking system in a real storage environment","authors":"Rupert Reif, W. Günthner, B. Schwerdtfeger, G. Klinker","doi":"10.1145/1503454.1503459","DOIUrl":"https://doi.org/10.1145/1503454.1503459","url":null,"abstract":"Order picking is one of the most important process steps in logistics. Because of their flexibility human beings cannot be replaced by machines. But if workers in order picking systems are equipped with a head-mounted display, Augmented Reality can improve the information visualization.\u0000 In this paper the development of such a system -- called Pick-by-Vision - is presented. The system is evaluated in a user study performed in a real storage environment. Important logistics figures as well as subjective figures were measured. The results show that a Pick-by-Vision system can improve considerably industrial order picking processes.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"232 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130716171","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}

{"title":"Virtual relighting of a Roman statue head from Herculaneum: a case study","authors":"J. Happa, M. Williams, G. A. Turley, G. Earl, Piotr Dubla, Gareth Beale, G. Gibbons, K. Debattista, A. Chalmers","doi":"10.1145/1503454.1503456","DOIUrl":"https://doi.org/10.1145/1503454.1503456","url":null,"abstract":"High-fidelity computer graphics offer the possibility for archaeologists to put excavated cultural heritage artefacts virtually back into their original setting and illumination conditions. This enables hypotheses about the perception of objects and their environments to be investigated in a safe and controlled manner. This paper presents a case study of the pipeline for the acquisition, modelling, rapid prototyping and virtual relighting of a Roman statue head preserved at Herculaneum in Italy. The statue head was excavated in 2006, after having been buried during the eruption of Mount Vesuvius in AD79.","PeriodicalId":325699,"journal":{"name":"International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa","volume":"29 34","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113955263","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}