How to Extend Visibility Polygons by Mirrors to Cover Invisible Segments

2017 ◽  
pp. 42-53 ◽  
Author(s):  
Arash Vaezi ◽  
Mohammad Ghodsi
Keyword(s):  
Visibility Polygons

Characterizing Link-2 LR-Visibility Polygons and Related Problems

2019 ◽  
Vol E102.A (2) ◽  
pp. 423-429
Author(s):  
Xuehou TAN ◽  
Bo JIANG
Keyword(s):  
Visibility Polygons

Simple Characterization of LR-visibility Polygons

2011 ◽  
pp. 176-187
Author(s):  
Xuehou Tan ◽  
Jing Zhang ◽  
Bo Jiang
Keyword(s):  
Simple Characterization ◽  
Visibility Polygons

VISIBILITY STABS AND DEPTH-FIRST SPIRALLING ON LINE SEGMENTS IN OUTPUT SENSITIVE TIME

2000 ◽  
Vol 10 (05) ◽  
pp. 535-552 ◽  
Author(s):  
MARK KEIL ◽  
DAVID M. MOUNT ◽  
S. K. WISMATH
Keyword(s):  
Practical Method ◽  
Visibility Graph ◽  
New Technique ◽  
Line Segments ◽  
Depth First Search ◽  
On Line ◽  
A New Technique ◽  
Visibility Polygons

Given a set S of n non-intersecting line segments in the plane, we vpresent a new technique for efficiently traversing the endpoint visibility graph of S to solve a variety of visibility problems in output sensitive time. In particular, we develop two techniques to compute the 2n visibility polygons of the endpoints of S, in output sensitive time. Depth-first spiralling is a technique that relies on the ordered endpoint visibility graph information to traverse the endpoints of S in a spiral-like manner using a combination of Jarvis' March and depth-first search. It is a practical method and has been implemented in C++ using LEDA.

scholarly journals Vertex Guarding in Weak Visibility Polygons

2015 ◽  
pp. 45-57
Author(s):  
Pritam Bhattacharya ◽  
Subir Kumar Ghosh ◽  
Bodhayan Roy
Keyword(s):  
Visibility Polygons

scholarly journals Redirected Walking in Static and Dynamic Scenes Using Visibility Polygons

2021 ◽  
pp. 1-1
Author(s):  
Niall L. Williams ◽  
Aniket Bera ◽  
Dinesh Manocha
Keyword(s):  
Dynamic Scenes ◽  
Redirected Walking ◽  
Visibility Polygons

Space decomposition based on visible objects in an indoor environment

2021 ◽  
pp. 239980832110373
Author(s):  
Kimia Amoozandeh ◽  
Stephan Winter ◽  
Martin Tomko
Keyword(s):  
Indoor Environment ◽  
Verbal Description ◽  
Two Dimensional ◽  
Space Decomposition ◽  
Visibility Polygons ◽  
Visual Range

When a person moves, the set of objects in their visual range changes. Hence, the set of objects perceived from a specific range of locations may be considered as a signature (possibly non-unique) of this region and be used for the localization of this person. In the case of fixed objects, the number of regions with a set of specific visible objects is limited. A verbal description containing references to elements of this set of visible objects could then be used to localize a person in the space. This paper proposes an approach for decomposing a space into regions that are characterized by such sets of visible objects. In our approach, at least a portion of partial surfaces of an object must be visible (beyond single points) to make part of the signature. Our method calculates two-dimensional visibility polygons for a portion of an object’s surface. Overlaying these polygons, we partition the space in regions of visibility signatures. The approach has been implemented, and we demonstrate how to represent space by qualitative locations using these visibility signatures. We further show how this representation can be used to locate a person within a space by a set of visible objects.

scholarly journals Characterizing and recognizing LR-visibility polygons

2014 ◽  
Vol 165 ◽  
pp. 303-311 ◽  
Author(s):  
Xuehou Tan ◽  
Bo Jiang ◽  
Jing Zhang
Keyword(s):  
Visibility Polygons

scholarly journals Characterizing and recognizing weak visibility polygons

1993 ◽  
Vol 3 (4) ◽  
pp. 213-233 ◽  
Author(s):  
Subir Kumar Ghosh ◽  
Anil Maheshwari ◽  
Sudebkumar Prasant Pal ◽  
Sanjeev Saluja ◽  
C.E. Veni Madhavan
Keyword(s):  
Visibility Polygons

scholarly journals Dynamic Algorithms for Visibility Polygons in Simple Polygons

2020 ◽  
Vol 30 (01) ◽  
pp. 51-78
Author(s):  
R. Inkulu ◽  
K. Sowmya ◽  
Nitish P. Thakur
Keyword(s):  
Line Segment ◽  
Time Complexity ◽  
Simple Polygon ◽  
Incremental Algorithm ◽  
Dynamic Algorithms ◽  
Insertions And Deletions ◽  
Shortest Path Trees ◽  
Query Algorithm ◽  
Fixed Line ◽  
Visibility Polygons

We devise the following dynamic algorithms for both maintaining as well as querying for the visibility and weak visibility polygons amid vertex insertions and deletions to the simple polygon. A fully-dynamic algorithm for maintaining the visibility polygon of a fixed point located interior to the simple polygon amid vertex insertions and deletions to the simple polygon. The time complexity to update the visibility polygon of a point [Formula: see text] due to the insertion (resp. deletion) of vertex [Formula: see text] to (resp. from) the current simple polygon is expressed in terms of the number of combinatorial changes needed to the visibility polygon of [Formula: see text] due to the insertion (resp. deletion) of [Formula: see text]. An output-sensitive query algorithm to answer the visibility polygon query corresponding to any point [Formula: see text] in [Formula: see text] amid vertex insertions and deletions to the simple polygon. If [Formula: see text] is not exterior to the current simple polygon, then the visibility polygon of [Formula: see text] is computed. Otherwise, our algorithm outputs the visibility polygon corresponding to the exterior visibility of [Formula: see text]. An incremental algorithm to maintain the weak visibility polygon of a fixed-line segment located interior to the simple polygon amid vertex insertions to the simple polygon. The time complexity to update the weak visibility polygon of a line segment [Formula: see text] due to the insertion of vertex [Formula: see text] to the current simple polygon is expressed in terms of the sum of the number of combinatorial updates needed to the geodesic shortest path trees rooted at [Formula: see text] and [Formula: see text] due to the insertion of [Formula: see text]. An output-sensitive algorithm to compute the weak visibility polygon corresponding to any query line segment located interior to the simple polygon amid both the vertex insertions and deletions to the simple polygon. Each of these algorithms requires preprocessing the initial simple polygon. And, the algorithms that maintain the visibility polygon (resp. weak visibility polygon) compute the visibility polygon (resp. weak visibility polygon) with respect to the initial simple polygon during the preprocessing phase.

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