Papers by Ivana Kolingerová
Solutions for the common problem of path planning in an abstract environment have been extensivel... more Solutions for the common problem of path planning in an abstract environment have been extensively studied in many scientific disciplines. However, many explored techniques assume the environment does not change and that there is a complete and detailed overview of this examined space. In addition, many path planning methods need to derive a specific graph structure from the environment representation
Surface Reconstruction from Large Point Clouds Using Virtual Shared Memory Manager
Lecture Notes in Computer Science, 2006
ABSTRACT Surface reconstruction is a common problem in computer graphics. Given a set of points s... more ABSTRACT Surface reconstruction is a common problem in computer graphics. Given a set of points sampled from some surface, a triangle mesh interpolating or approximating the points is to be obtained. One of very often used techniques for solving this problem is the selection of surface triangles from the set of Delaunay tetrahedronization faces. In the case of large data, it is difficult to obtain the tetrahedronization due to its huge memory requirements. One of possible solutions is to use distributed computing. Here, we describe the newly developed VSM (Virtual Shared Memory) distributed toolkit and its utilization for the task of surface reconstruction. By our approach, we were able to process dataset having 1.4M points on 4xP4 interconnected via 100Mb Ethernet in 6 hours. About 5GB of memory was consumed during the reconstruction.
A Proper Choice of Vertices for Triangulation Representation of Digital Images
Lecture Notes in Computer Science, 2010
Representation of the digital image by a triangulation does not bring a high compression but enab... more Representation of the digital image by a triangulation does not bring a high compression but enables geometric transformations and is very simple. In this paper we will show that it is also possible to choose the triangulation vertices randomly, then their [x,y] position does not need to be stored as it can be easily reconstructed during decoding. We show how
Parallel Delaunay triangulation based on circum-circle criterion
Proceedings of the 18th spring conference on Computer graphics - SCCG '03, 2003
This paper describes a newly proposed simple and efficient parallel algorithm for the constructio... more This paper describes a newly proposed simple and efficient parallel algorithm for the construction of the Delaunay triangulation (DT) in E2 by randomized incremental insertion. The construction of the DT is one of the fundamental problems in computer graphics. The proposed algorithm is designed for parallel systems with shared memory and several processors. Such hardware (especially with two-processors) became available
Fast Delaunay stripification
Proceedings of the 18th spring conference on Computer graphics - SCCG '03, 2003
2D and 2.5D triangulations belong nowadays among the most often types of geometric object descrip... more 2D and 2.5D triangulations belong nowadays among the most often types of geometric object description in computer graphics. a frequent application is, e.g., terrain modeling. Therefore the problem of fast visualization of this type of data is often solved. One possible approach is the reduction of data duplicities by using triangle strips.This paper describes a new stripification algorithm for models,
Our approach to image region approximation offers a complete scheme consisting of several steps. ... more Our approach to image region approximation offers a complete scheme consisting of several steps. We separate the encoding of region boundaries from the tex- ture description. The original image is first segmented using an unsupervised segmentation method for color- texture regions. Following polygonal approximation of created regions causes the degradation of region bounda- ries. The triangulation is then applied to
We present a new algorithm for morphing simple polygons that is inspired by growing forms in natu... more We present a new algorithm for morphing simple polygons that is inspired by growing forms in nature. While previous algorithms require user-assisted definition of complicated correspondences between the morphing objects, our algorithm defines the correspondence by overlapping the input polygons. Once the morphing of one object into another is defined, very little or no user interaction is necessary to achieve intuitive results. Our algorithm is suitable namely for growth-like morphing. We present the basic algorithm and its three variations. One of them is suitable mainly for convex polygons, the other two are for more complex polygons, such as curved or spiral polygonal forms.
Early Warning System for Air Traffic Control Using Kinetic Delaunay Triangulation
Lecture Notes in Computer Science, 2010
We describe the current methodology used in the air traffic control and show how the kinetic Dela... more We describe the current methodology used in the air traffic control and show how the kinetic Delaunay triangulation may be used to predict potentially dangerous situations of two aircrafts on a crash course. We use a real data obtained from the radar readings of the air space of the Czech Republic and process this data in order to create and
Fast method for computation of channels in dynamic proteins
Morphing of meshes with attributes
Proceedings of the 20th spring conference on Computer graphics - SCCG '04, 2004
A morphing or metamorphosis is a process of smoothly transforming one geometric object into anoth... more A morphing or metamorphosis is a process of smoothly transforming one geometric object into another. This technique is mainly used in computer animation. Our work deals with genus 0 objects given in boundary representation. Most of existing techniques process only geometric information and do not consider any other surface attributes as normals, colors, opacity, texture coordinates etc. But these attributes
Multi-path algorithm for triangle strips
Proceedings Computer Graphics International, 2004., 2004
Triangle surface models belong to the most popular type of geometric objects description in compu... more Triangle surface models belong to the most popular type of geometric objects description in computer graphics. Therefore, the problem of fast visualization of this type of data is often solved. One of popular approaches is stripification, i.e., a conversion of triangle surface into strips of triangles. This enables to reduce the rendering time by reduction data size and by avoiding
Tensor product surfaces as rewriting process
Page 1. Tensor Product Surfaces as Rewriting Process Ivana Kolingerová ∗ University of West Bohem... more Page 1. Tensor Product Surfaces as Rewriting Process Ivana Kolingerová ∗ University of West Bohemia Czech Republic Petr März University of West Bohemia Czech Republic Bedrich Bene Purdue University USA Figure ...
Visual Computer, 2003
The randomized incremental insertion algorithm of Delaunay triangulation in E 3 is very popular d... more The randomized incremental insertion algorithm of Delaunay triangulation in E 3 is very popular due to its simplicity and stability. This paper describes a new parallel algorithm based on this approach. The goals of the proposed parallel solution are not only to make it efficient but also to make it simple. The algorithm is intended for computer architectures with several processors and shared memory. Several versions of the proposed method were tested on workstations with up to eight processors and on datasets of up to 200 000 points with favorable results.
The Employment of Regular Triangulation for Constrained Delaunay Triangulation
Lecture Notes in Computer Science, 2004
We demonstrate a connection between a regular triangulation and a constrained Delaunay triangulat... more We demonstrate a connection between a regular triangulation and a constrained Delaunay triangulation in 2D. We propose an algorithm for edge enforcement in the constrained Delaunay triangulation based on the use of regular triangulation. As far as we know, such a connection has not been presented yet in the literature and there is no algorithm based on this idea, too.
Post-optimization of Delaunay tetrahedrization
Proceedings Spring Conference on Computer Graphics, 2001
Abstract: This paper brings results of post-optimization of Delaunay tetrahedrization. Delaunay t... more Abstract: This paper brings results of post-optimization of Delaunay tetrahedrization. Delaunay triangulation is very popular method to create 2D meshes but in 3D its properties are not as good as in 2D and can be improved. For this improvement an existing method was used: local transformations-so called flips-performed in order to improve different geometrical properties of tetrahedral and applied to
In the last couple of years, very detailed high-resolution terrain data sets have become availabl... more In the last couple of years, very detailed high-resolution terrain data sets have become available thanks to new acquisition techniques, e.g., the airbone laser scanning. Such data sets contain, typically, several millions of points and, therefore, several giga- bytes are required to store them. As common computers are able to address up to 2GB of physical memory only, these large data sets cannot be processed in one piece. It makes their processing complex and time consuming. In this paper, we propose a distributed solution that overcomes this disadvantage. The terrain data set is represented by the Delaunay triangulation stored in local memories of computers interconnected by a network. The proposed method allows dynamic changes of this triangulation, i.e., points can be successively inserted or removed, and, therefore, the use of our approach for view-dependent visualization based on LOD technique is straightforward. Let us note that due to the distributed computing, applications...
The Visual Computer, 2002
The paper describes a new parallel algorithm of Delaunay triangulation based on randomized increm... more The paper describes a new parallel algorithm of Delaunay triangulation based on randomized incremental insertion. The algorithm is practical, simple and can be modified also for constrained triangulation or tetrahedralization. It was developed for architectures with a lower degree of parallelism, such as several-processor workstations, and tested on up to 8 processors.
This paper presents several parallel algorithms for the construction of the Delaunay triangulatio... more This paper presents several parallel algorithms for the construction of the Delaunay triangulation in E 2 and E 3 -one of the fundamental problems in computer graphics. The proposed algorithms are designed for parallel systems with shared memory and several processors. Such a hardware configuration (especially the case with two-processors) became widely spread in the last few years in the computer graphics area. Some of the proposed algorithms are easy to be implemented but not very efficient, while some of them prove opposite characteristics. Some of them are usable in E 2 only, other work in E 3 as well. The algorithms themselves were already published in computer graphics where the computer graphics criteria were highlighted. This paper concentrates on parallel and systematic point of view and gives detailed information about the parallelization of a computational geometry application to parallel and distributed computation oriented community.
Fast Computation of Vertex Normals for Linearly Deforming Meshes
Journal of Graphics, GPU, and Game Tools, 2007
In this paper, we deal with shading of linearly deforming triangular meshes that deform in time s... more In this paper, we deal with shading of linearly deforming triangular meshes that deform in time so that each vertex travels independently along its linear trajectory. We will show how the vertex normal can be computed efficiently for an arbitrary triangular polygon mesh under linear deformation using the weighting scheme referred to by Jin et al. as "mean weighted by areas of adjacent triangles." Our computation approach is also faster than simple normal recomputation. Moreover, it is more accurate than the usual linear interpolation. The proposed approach is general enough to be used to compute the vertex normal for any number of adjacent faces.
An incremental construction algorithm for Delaunay triangulation using the nearest-point paradigm
International Journal of Geographical Information Science, 2003
... The algorithm should be fast. ... 3.3. Constructing Delaunay triangulation The algorithm forc... more ... The algorithm should be fast. ... 3.3. Constructing Delaunay triangulation The algorithm forconstructing Delaunay triangulation is described very briefly because it is in principle the same as other incremental insertion triangulation algorithms (details can be found in de Berg et al ...
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Papers by Ivana Kolingerová