Progressive transmission of 3D object based on balls and cones union from medial axis transformation

Author(s):  
F. Dupont ◽  
B. Gilles ◽  
A. Baskurt
2018 ◽  
Vol 115 ◽  
pp. 1-11 ◽  
Author(s):  
Yimin C. Wang ◽  
Michael J. Pyrcz ◽  
Octavian Catuneanu ◽  
Jeff B. Boisvert
Keyword(s):  

2020 ◽  
Vol 9 (5) ◽  
pp. 304
Author(s):  
Elżbieta Lewandowicz ◽  
Paweł Flisek

The centerlines of polygons can be generated with the use of various methods. The aim of this study was to propose an algorithm for generating the centerline of an elongated polygon based on the transformation of vector data. The proposed method involves the determination of base points denoting the direction of river flow. These points were also used to map two polygon boundaries. A Triangulated Irregular Network (TIN) was created based on the polygon’s breakpoints. Edges that intersect the river channel in a direction perpendicular to river flow (across) were selected from a set of TIN edges. The polygon was partitioned into segments with the use of the selected TIN edges. The midpoints of selected TIN edges were used to generate the polygon’s centerline based on topological relations. The presented methodology was tested on a polygon representing a 15-km-long section of a river intersecting the city of Olsztyn (a university center). The analyzed river is a highly meandering watercourse, and its channel is narrowed down by hydraulic structures. The river features an island and distributary channels. The generated centerline effectively fits the polygon, and, unlike the solution modeled with the Medial Axis Transformation (MAT) algorithm, it does not feature branching streams.


Author(s):  
Peter Vajda ◽  
Ivan Ivanov ◽  
Lutz Goldmann ◽  
Jong-Seok Lee ◽  
Touradj Ebrahimi

In this paper, the authors analyze their graph-based approach for 2D and 3D object duplicate detection in still images. A graph model is used to represent the 3D spatial information of the object based on the features extracted from training images to avoid explicit and complex 3D object modeling. Therefore, improved performance can be achieved in comparison to existing methods in terms of both robustness and computational complexity. Different limitations of this approach are analyzed by evaluating performance with respect to the number of training images and calculation of optimal parameters in a number of applications. Furthermore, effectiveness of object duplicate detection algorithm is measured over different object classes. The authors’ method is shown to be robust in detecting the same objects even when images with objects are taken from different viewpoints or distances.


2019 ◽  
Vol 8 (2) ◽  
pp. 60 ◽  
Author(s):  
Elżbieta Lewandowicz ◽  
Przemysław Lisowski ◽  
Paweł Flisek

Automatic methods for constructing navigation routes do not fully meet all requirements. The aim of this study was to modify the methodology for generating indoor navigation models based on the Medial Axis Transformation (MAT) algorithm. The simplified method for generating corridor axes relies on the Node-Relation Structure (NRS) methodology. The axis of the modeled structure (corridor) is then determined based on the points of the middle lines intersecting the structure (polygon). The proposed solution involves a modified approach to the segmentation of corridor space. Traditional approaches rely on algorithms for generating Triangulated Irregular Networks (TINs) by Delaunay triangulation or algorithms for generating Thiessen polygons known as Voronoi diagrams (VDs). In this study, both algorithms were used in the segmentation process. The edges of TINs intersected structures. Selected midpoints on TIN edges, which were located in the central part of the structure, were used to generate VDs. Corridor structures were segmented by polygon VDs. The identifiers or structure nodes were the midpoints on the TIN edges rather than the calculated centroids. The generated routes were not zigzag lines, and they approximated natural paths. The main advantage of the proposed solution is its simplicity, which can be attributed to the use of standard tools for processing spatial data in a geographic information system.


1982 ◽  
Vol PAMI-4 (4) ◽  
pp. 419-421 ◽  
Author(s):  
Shyuan Wang ◽  
Azriel Rosenfeld ◽  
Angela Y. Wu

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