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An adaptive algorithm for conversion from quadtree to chain codes
2001
Pattern Recognition
An adaptive algorithm is presented for converting the quadtree representation of a binary image to its chain code representation. ...
Our algorithm has the advantage of constructing the chain codes of the resulting quadtree of the Boolean operation of two quadtrees by re-using the original chain codes. ...
Otherwise, go back to step 2. Our adaptive conversion algorithm from quadtree to chain code is based on the 8-neighbor traversal algorithm [13] . ...
doi:10.1016/s0031-3203(00)00008-x
fatcat:sxvax54cgrewbp7e4tdgcwixo4
Using topological sweep to extract the boundaries of regions in maps represented by region quadtrees
1996
Algorithmica
The algorithm works for maps that contain multiple regions as well as holes. The algorithm makes use of active objects (in the form of regions) and an active border. ...
The algorithm works for many different quadtree representations including those where the quadtree is stored in external storage. ...
Of course, other representations of the boundary (e.g., chain codes [12] ) are also possible, and the algorithms of this paper can be readily adapted to produce them. ...
doi:10.1007/bf01942608
fatcat:52ejo35uprabrhvxxeus2ojfkm
An Overview of Quadtrees, Octrees, and Related Hierarchical Data Structures
[chapter]
1988
Theoretical Foundations of Computer Graphics and CAD
An overview of hierarchical data structures for representing images, such as the quadtree and octree, is presented. They are based on the principle of recursive decomposition. ...
There is a greater emphasis on region data (i.e., 2-dimensional shapes) and to a lesser extent on point, lin.e, and 3-dimension-al data. ...
The ability to perform set operations quickly is one of the primary reasons for the popularity of quadtrees over alternative representations such as the chain code or vectors. ...
doi:10.1007/978-3-642-83539-1_2
fatcat:woensntuqnhmxplj5f626mscsm
Block-run run-length coding of handwriting and bilevel graphics based on quadtree segmentation
1997
Pattern Recognition Letters
An efficient off-line coding scheme for handwriting and bilevel graphics based on quadtree segmentation and block-run run-length coding (RLC) is presented. ...
higher coding efficiency than the conventional one-dimensional RLC and its bit rate is close to that of on-line dynamographical chain coding. © 1997 Elsevier Science B.V. ...
In order to apply the off-line coding scheme to the on-line handwriting data, a transcoding algorithm was used to convert the on-line handwriting data into the off-line raster scanning bit pattern. ...
doi:10.1016/s0167-8655(96)00133-x
fatcat:aqoszr7lhfgtdlmtw3hep5pa2y
Spatial Indexing for Location-Aware Systems
2007
2007 Fourth Annual International Conference on Mobile and Ubiquitous Systems: Networking & Services (MobiQuitous)
It establishes the principles and requirements of a wide-area spatial indexer, reviews the R-tree, Quadtree and RQ-tree methods proposed before for indoor location-awareness, and significantly adapts the ...
The proposed indexing method uses a combination of R-trees (for high level spatial information, down to structural level) and Quadtrees (for lower level representation of objects). ...
Conversely, in an indoor environment, it has proven more useful for a location-aware service to avoid user query initiation. ...
doi:10.1109/mobiq.2007.4451027
dblp:conf/mobiquitous/Harle07
fatcat:xpsx5g2wznbj7dznhmukdkimsy
On the size of quadtrees generalized to d-dimensional binary pictures
1985
Computers and Mathematics with Applications
Among these results are a comparison of the space-efficiency of linear vs regular trees, in terms of both the number of nodes of the tree and the number of bits needed to store each node, and an upper ...
S~meresu~tsaboutthesize~fquadtreesand~inearq~dtrees'usedt~r~pres~ntbinary2 ~ x 2" digital pictures, are generalized to d-dimensional 2" x . . . x 2" pictures. ...
Acknowledgement--The author wishes to thank Prof. I. Gargantini for posing these problems and giving valuable assistance in the preparation of the Introduction and Section I of this article. ...
doi:10.1016/0898-1221(85)90187-7
fatcat:vkmjwi6ry5dzbc3unjhlfdmboa
Hierarchical data structures and algorithms for computer graphics. I. Fundamentals
1988
IEEE Computer Graphics and Applications
While such data structures are not necessary for the processing of simple scenes, they are central to the efficient processing of large-scale realistic scenes. ...
Object-space hierarchies are discussed briefly, but the main emphasis is on hierarchies constructed in the image space, such as quadtrees and oc t rees. ...
Average-case analysis for the execution time of the chain-code-to-raster-quadtree algorithm is linear in the length of the chain code, as shown by analysis" in conjunction with the quadtree complexity ...
doi:10.1109/38.513
fatcat:aoqboxnwx5gnzoenouseefauby
The Quadtree and Related Hierarchical Data Structures
1984
ACM Computing Surveys
A tutorial survey is presented of the quadtree and related hierarchical data structures. They are based on the principle of recursive decomposition. ...
There is a greater emphasis on region data (i.e., two-dimensional shapes) and to a lesser extent on point, curvilinear, and threedimensional data. ...
Thus it is useful to be able to construct a quadtree from a chain code representation of a binary image. Such an algorithm described by Samet [1980a] is briefly outlined below. ...
doi:10.1145/356924.356930
fatcat:3q363g3xondbjivox43umdusjm
Algebraic Topological Analysis of Time-Sequence of Digital Images
[chapter]
2005
Lecture Notes in Computer Science
Our answer is based on an algebraictopological coding, called AT-model, for a nD (n = 2, 3) digital binaryvalued image I consisting simply in taking I together with an algebraic object depending on it. ...
Considering AT-models for all the 2D digital images in a time sequence, it is possible to get an AT-model for the 3D digital image consisting in concatenating the successive 2D digital images in the sequence ...
There is an algorithm calculating an AT-model for I. ...
doi:10.1007/11555964_18
fatcat:yl4cteadzjfdlph4tzfe6m2wza
Multiresolution rendering by sewing trimmed NURBS surfaces
2002
Proceedings of the seventh ACM symposium on Solid modeling and applications - SMA '02
and this way they do not provide an automatic solution to create large connected models just from a set of surfaces. ...
For their efficient rendering multiresolution models are needed. To create such models without artifacts at the trimming curves, one needs to sew parts together along the common boundaries. ...
If we want to guarantee a κ error on the boundaries, we can achieve this by choosing a general ε = κ 3 for the quadtree algorithm and an appropriate δ = κ−2 bl for a linear approximation (e.g. using midpoint ...
doi:10.1145/566282.566323
dblp:conf/sma/KahleszBK02
fatcat:47jp6vwdzvax7ezopeciakwgkm
Multiresolution rendering by sewing trimmed NURBS surfaces
2002
Proceedings of the seventh ACM symposium on Solid modeling and applications - SMA '02
and this way they do not provide an automatic solution to create large connected models just from a set of surfaces. ...
For their efficient rendering multiresolution models are needed. To create such models without artifacts at the trimming curves, one needs to sew parts together along the common boundaries. ...
If we want to guarantee a κ error on the boundaries, we can achieve this by choosing a general ε = κ 3 for the quadtree algorithm and an appropriate δ = κ−2 bl for a linear approximation (e.g. using midpoint ...
doi:10.1145/566313.566323
fatcat:bhurktxbczhfrjrv2lpb33kydi
ForestClaw: A parallel algorithm for patch-based adaptive mesh refinement on a forest of quadtrees
[article]
2017
arXiv
pre-print
We have implemented this algorithm in the ForestClaw code using single-grid solvers from ClawPack, a software package for solving hyperbolic PDEs using finite volumes methods. ...
We describe a parallel, adaptive, multi-block algorithm for explicit integration of time dependent partial differential equations on two-dimensional Cartesian grids. ...
The authors gratefully acknowledge the Gauß Centre for Supercomputing (GCS) for providing computing time through the John von Neumann Institute for Com- ...
arXiv:1703.03116v1
fatcat:oqrjj3l42rby3c6pmbdptczvqi
The chordlet transform with an application to shape compression
2012
Signal processing. Image communication
A data structure, the fat quadtree and an algorithm for determining an optimal chordlet representation of an image are proposed. ...
We propose to extend the line-based dictionary of the beamlet framework to one that includes sets of arcs that are quantized in height. ...
Due to the introduction and adoption of the new fat quadtree structure, this algorithm must be adapted. ...
doi:10.1016/j.image.2011.09.001
fatcat:fa6q3237tvgabikijebmh2e3lq
Triangulating the Square and Squaring the Triangle: Quadtrees and Delaunay Triangulations are Equivalent
2012
SIAM journal on computing (Print)
Our main tool for the second algorithm is the well-separated pair decomposition(WSPD), a structure that has been used previously to find Euclidean minimum spanning trees in higher dimensions (Eppstein) ...
More precisely, we give two algorithms: the first computes a compressed quadtree for a planar point set, given the Delaunay triangulation; the second finds the Delaunay triangulation, given a compressed ...
We would like to thank the group at Carleton and especially our hosts Jit Bose and Pat Morin for their wonderful hospitality and for creating a great research environment. ...
doi:10.1137/110825698
fatcat:bokamjbnyvetpko26ulgv3laza
A quadtree-adaptive spectral wave model
2010
Ocean Modelling
For the case of a cyclone-generated wave field, the cost of the adaptive method increases linearly with spatial resolution compared to quadratically for constant-resolution methods. ...
This equivalence facilitates the generalisation of GSE alleviation techniques to quadtree grids. ...
This development was made possible by the availability of source codes for both Gerris (Popinet, 2009c; Popinet, 2009d) and WAVEWATCH III. ...
doi:10.1016/j.ocemod.2010.04.003
fatcat:temov6s5vvfp5hs45anjirjy4y
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