WSCG '2011: Poster Paper Proceedings
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Item An efficient approach to direct NURBS(Václav Skala - UNION Agency, 2011) Sisojevs, Aleksandrs; Glazs, Aleksandrs; Skala, VáclavRay tracing is a popular method for generating high quality images. NURBS surface is a popular tool for 3D modeling. There are different approaches to NURBS surface visualization by ray tracing methods. But these methods of computer graphics do not solve this task at an expected level. Therefore in this paper the authors propose to use a new effective approach for NURBS surface visualization by ray tracing method to render objects with high accuracy and quality.
Item Use of virtual reality and constraint programming techniques in interactive 3D objects layout(Václav Skala - UNION Agency, 2011) Kefi, Marouene; Richard, Paul; Barichard, Vincent; Skala, VáclavIn this paper, we propose innovative system in order to assist the user in a 3D objects layout context. Through a combination between virtual reality (VR) and constraint programming (CP) technique, user's 3D interaction and manipulation will be translated to incoming queries of a constraints solver which propagate constraints and generate a new possible solution. The computed solution is transmitted, as new positions of 3D objects, to virtual environment (VE) which reconfigures itself. We focus in this paper on the architecture of our system and we describe the implementation of several constraints and some first results.Item Interactive bivariate mode tree(Václav Skala - UNION Agency, 2011) Florek, Martin; Hauser, Helwig; Skala, VáclavKernel density estimation (KDE) is widely used statistical method to study distribution of the data. The problem with this method is choosing the right bandwidth. In our work we focus on semiautomatic bandwidth selection with the use of visual paradigm of the Mode Tree. We not only enhanced the bivariate mode tree visualization, which was only sketched by the authors, but we also developed a hybrid CPU/GPU implementation to improve the speed of the mode tree construction. Keywords: Mode Tree, Data Visualization, Kernel Density Estimation, GPU.Item Improving the visualization of galactic events using Pixarʼs RenderMan(Václav Skala - UNION Agency, 2011) Cassidy, Paul; Kilburn, Tyler; Salemink, Vincent; Bailey, Reynold; Bischof, Hans-Peter; Skala, VáclavPixar’s PhotoRealistic RenderMan® is a powerful graphics rendering system with underexplored potential for visualizing scientific data. We utilized PhotoRealistic RenderMan® to visualize simulations of galaxy mergers which are dynamic and contain large volumes of multidimensional data. Our goal was to emulate existing astronomical imagery such as images captured by the Hubble Space Telescope. In order to accomplish this we developed techniques for rendering individual stars and also took into account factors such as galaxy density. PhotoRealistic RenderMan® was used to create a movie from the provided galaxy merger data. In this paper we describe our approach and present the results. We also discuss how the rendering framework can be extended to incorporate the effects of light bending due to gravity.Item 3D extension of web(Václav Skala - UNION Agency, 2011) Běhal, David; Dadová, Jaroslava; Uhlíková, Ivana; Skala, VáclavIn our work, we propose our application of 3D graphics inside the web browser. Nowadays, internet and web browsers are not only space, where user can read information, but it is space also for collaboration and experience. Therefore we propose new ideas how should browsing a modern web page look like with use of state-of-the-art technology and possibilities. Users expect from the displayed application more interesting features, not only display of static text. Standard layout of a web page is based on list of a newspaper or a book. This layout is obsolete and does not fit modern approach in new technologies. Our method of displaying content and information inside the web browser is with full 3D, not only embedding 3D as a special feature inside a small part of web page. In this article we also include virtual Theatre as a case study for this problem and explain possibilities of information display and reasons why is 3D better than 2D in this case.Item Construction of panoramic depth image(Václav Skala - UNION Agency, 2011) Nishio, Koji; Hiraoka, Keiko; Yamashita, Chikara; Kobori, Ken-ichi; Skala, VáclavWe propose a method which constructs a panoramic depth image. We use a digital still camera and a panoramic lens. The lens has omnidirectional mirror that is pointed in the camera direction and the camera can shoot a horizontal panoramic image through it. We use two panoramic images to construct a panoramic depth image. Each image is photographed at different height and there is the parallax difference between these images. Our method seeks corresponding point between these images and calculates the depth value at each pixel. In addition, we had some experience to evaluate effectiveness of our method. The results shows that our method is useful for making three-dimensional contents form the real scenery.Item An exact hierarchical geometric model: combining remeshing and spatial decomposition(Václav Skala - UNION Agency, 2011) Martinez, A.; Jimenez, J.; Paulano, F.; Pulido, R.; Feito, F.; Skala, VáclavThe use of hierarchical spatial decomposition in 3D scenes in order to manage the complexity of the objects is a well known approach. The main problem with this technique is the updating process when the mesh is modified. Any deformation or rotation means a new complete reconstruction of the structure. By other way remeshing techniques modify the structure of a mesh in order to achieve a given quality requirement. In this study a combination of remeshing techniques and hierarchical spatial decomposition is presented. Our goal is to develop an new model applying a remeshing process based on the hierarchical structure elements. This new model allows to extend one deformation in the spatial decomposition to the mesh. The tetra-tree is chosen as the spatial decomposition because of its advantages in relation to the remeshing algorithm. Tests with medium meshes with the new model were performed with good results.Item Parametric 3D model of sperm cell surface applied in confocal microscopy(Václav Skala - UNION Agency, 2011) Marek, Jozef; Uhrinová, Ivana; Demjen, Erna; Tomori, Zoltán; Skala, VáclavConfocal microscopy combined with 3D graphics enable to study spatial characteristics of biological objects on microscopic level. Human sperm cells have a typical shape with marked asymmetry in its frontal-back part. 2D analysis with optical microscope gives mainly information about horizontal plane of the cell. Presented parametrical model provides important geometrical parameters describing 3D shape of the cell surface using 3D reconstruction of horizontal cross-sections acquired by a confocal microscope.Item Deformation exchange between adjacent physical code geometries(Václav Skala - UNION Agency, 2011) Duplex, Benjamin; Gesquière, Gilles; Daniel, Marc; Perdu, Fabien; Skala, VáclavPhysical codes are dependent on a discipline and describe the reality through equations solved on a geometry. Strong links, or couplings, between them are set up to increase the result accuracy, leading to data exchanges. Mechanical codes calculate geometrical deformations which must be tranferred by couplings. Their direct exchange is generally impossible if coupled codes compute with different models of the same geometry (in practice different meshes). Moreover, two meshes can only share border(s). This paper focuses on this case: one mesh must follow the border deformation of the mechanical code mesh.Item Generation of Indian ink painting image from two-dimensional image data(Václav Skala - UNION Agency, 2011) Kobori, Kenichi; Maekawa, Naomi; Nishio, Koji; Skala, VáclavRecently, non-photorealistic image rendering (NPR) has become the subject of research and development by many researchers due to a rapid improvement in computer graphics. NPR has been used for communication by emphasizing an image or to simulate existing painting techniques. In this paper, we propose a generation method for Indian ink painting image which is an Oriental painting technique from two-dimensional realistic image. In general, Indian ink painting has three kinds of drawing techniques, “Senbyo “ technique to draw only contours of objects, “Mokkotu“ technique to draw only the interior of objects and “Senzen” technique to draw both contours and the interior of objects. In this paper, we simulate Indian ink painting by “Senzen” technique. We extract the contours from two-dimensional realistic image and decide the interior of the object in order to generate the image which is drawn by “Senzen” technique. The final image is generated by combining the inner area of the object with the contours. We generated several Indian ink painting images by our method. The experimental results show that the proposed method is effective for Indian ink painting image rendering.Item Comparison of mean shift algorithms and evaluation of their stability(Václav Skala - UNION Agency, 2011) Šrubař, Štěpán; Šurkala, Milan; Skala, VáclavMean Shift is an universal and robust segmentation algorithm used also for image segmentation. Implementation corresponding to definition is slow for real-time image processing, thus some faster variants were proposed. Speed and quality of the segmentation can be influenced by the variant of the algorithm as well as by setting its parameters. Modification of a parameter causes change of number of segments and their shape as well. By using segmentation evaluation algorithm, we analyze and present these changes for original and modified Mean Shift algorithms. Influence of noise is also studied.Item Fast temporal filtering of depth maps(Václav Skala - UNION Agency, 2011) Matyunin, Sergey; Vatuolin, Dmitriy; Smirnov, Maxim; Skala, VáclavIn this paper, we propose a method of filtering depth maps that are automatically generated from video sequences using optical flow, 3D reconstruction and scene analysis methods. To attain better quality, information from both the source video and depth map is used. The proposed algorithm uses motion estimation to take into account temporal information, but the algorithm’s structure permits use of optical flow to improve quality, but at the expense of greater computation time. The method can be applied as a preprocessing stage for enhancement of multi-view or stereo video. Joint temporal and spatial processing can yield further improvements in quality. A comparison of the results with test ground-truth sequences using the BI-PSNR metric is presented.Item Computer simulation and visualization of mechanical wave propagation phenomena in continuous medium(Václav Skala - UNION Agency, 2011) dos Santos, Rodrigo Mologni G.; de Martino, José Mario; de Mesquita Neto, Euclides; Skala, VáclavThis paper presents a simulation software for mechanical wave propagation phenomena and a visualization environment developed to help the analysis of the numerically synthesized dynamic solutions of boundary value problems of solid mechanics. The simulation software is used by researchers and engineers to study and gain insights into complex problems related to the mechanics of continuous media. The large amount of data generated by the numerical solution of wave propagation problems makes the interpretation of the results a hard daunting task without the support of techniques to graphically display these data. The visualization environment that was developed supports different visualization strategies of a variety of parameters and it has been used to improve the understanding of the simulation results and to validate the numerical simulator as well as the underlying mathematical-physical modeling.
