Abstract
An offset discretization of a set \(X \subset {\mathbb {R}}^n\) is obtained by taking the integer points inside a closed neighborhood of X of a certain radius. In this work we determine a minimum threshold for the offset radius, beyond which the discretization of an arbitrary (possibly disconnected) set is always connected. The obtained results hold for a broad class of disconnected subsets of \({\mathbb {R}}^n\) and generalize several previous results. We also extend our results to infinite discretizations of unbounded subsets of \({\mathbb {R}}^n\) and consider certain algorithmic aspects. The obtained results can be applied to component topology preservation as well as extracting geometric features and connectivity control of very large object discretizations.
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Notes
The function g itself, defined on the subsets of \({\mathbb {R}}^n\) is called a gap functional. See, e.g. Beer (1993) for more details.
References
Andres E (1994) Discrete circles, rings and spheres. Comput Graphics 18(5):695–706
Andres E (2003) Discrete linear objects in dimension n: the standard model. Graph Models 65(1):92–111
Anton F, Emiris I, Mourrain B, Teillaud M (2005) The offset to an algebraic curve and an application to conics. In: ICCSA, lecture notes in computer science, vol 3480, pp 1–21. Springer
Arcelli C, Sanniti di Baja G (1996) Skeletons of planar patterns. In: Kong TY, Rosenfeld A (eds) Topological algorithms for digital image processing, machine intelligence and pattern recognition, vol 19. Elsevier, Amsterdam, pp 99–143
Arrondo E, Sendra J, Sendra J (1999) Genus formula for generalized offset curves. J Pure Appl Algebra 136(3):199–209
Beer G (1993) Topologies on Closed and Closed Convex Sets, Mathematics and its Applications, vol 268. Kluwer, Dordrecht
Borgefors G, Ramella G, Sanniti di Baja G (2001) Shape and topology preserving multi-valued image pyramids for multi-resolution skeletonization. Pattern Recognit Lett 22(6):741–751
Brimkov B, Brimkov VE (2020) On connectedness of discretized sets. In: Lukić T et al (eds) Combinatorial Image Analysis, , Lecture Notes in Computer Science, vol 1248. Springer Nature, pp 18–26
Brimkov VE (2010) Connectedness of offset digitizations in higher dimensions. In: Barneva RP, Brimkov VE, Hauptman HA, Natal Jorge RM, Tavares JMRS (eds) Computational modeling of objects represented in images. Springer, Berlin, pp 36–46
Brimkov VE, Barneva RP, Brimkov B (2011) Connected distance-based rasterization of objects in arbitrary dimension. Graph Models 73(6):323–334
Campo TM (2016) Medical imaging for the health care provider: practical radiograph interpretation. Springer, New York
Cohen-Or D, Kaufman A (1997) 3D line voxelization and connectivity control. IEEE Comput Graphics Appl 17(6):80–87
Cox D, Little J, O’shea D (1998) Using algebraic geometry, graduate texts in mathematics, vol 185. Springer, New York
Debled-Rennesson I, Domenjoud E, Jamet D (2006) Arithmetic discrete parabolas. In: Bebis G, Boyle R, Parvin B, Koracin D, Remagnino P, Nefian A, Meenakshisundaram G, Pascucci V, Zara J, Molineros J, Theisel H, Malzbender T (eds) Advances in visual computing. Springer, Berlin, pp 480–489
Engelking R (1989) General topology. Revised and completed edition. Heldermann Verlag, Berlin
Figueiredo O, Reveillès JP (1996) New results about 3d digital lines. In: Vision Geometry V. vol. 2826, pp. 98–109. International Society for Optics and Photonics
Fiorio C, Jamet D, Toutant JL (2006) Discrete circles: an arithmetical approach with non-constant thickness. In: Vision Geometry XIV. vol. 6066, p. 60660C. International Society for Optics and Photonics
Gonzalez RC, Woods RE, Eddins SL (2020) Digital image processing using MATLAB, 3rd edn. Gatesmark
Hall RW, Kong TY, Rosenfeld A (1996) Shrinking binary images. In: Kong TY, Rosenfeld A (eds) Topological algorithms for digital image processing. Elsevier, Amsterdam, pp 31–98
Hoffman JD, Frankel S (2001) Numerical methods for engineers and scientists. CRC Press, Boca Raton
Hoffmann C, Vermeer P (1991) Eliminating extraneous solutions for the sparse resultant and the mixed volume. J Symb Geom Appl 1(1):47–66
Jonas A, Kiryati N (1997) Digital representation schemes for 3d curves. Pattern Recognit 30(11):1803–1816
Kardos P, Palágyi K (2017) On topology preservation of mixed operators in triangular, square, and hexagonal grids. Discrete Appl Math 216:441–448
Kaufman A, Cohen D, Yagel R (1993) Volume graphics. Computer 26(7):51–64
Kim CE (1983) Three-dimensional digital line segments. IEEE Trans Pattern Anal Mach Intell 2:231–234
Klette R, Rosenfeld A (2004) Digital geometry: geometric methods for digital picture analysis. Elsevier, Amsterdam
Kong T (2001) Digital topology. In: Davis LS (ed) Foundations of image understanding. Kluwer, Boston, pp 33–71
Krätzel E (1981) Zahlentheorie, vol 19. VEB Deutscher Verlag der Wissenschaften, Berlin
Kruskal JB (1956) On the shortest spanning subtree of a graph and the traveling salesman problem. Proc Am Math Soc 7(1):48–50
Marschner S (2018) Fundamentals of computer graphics, 4th edn. CRC Press, Boca Raton
McAllister M, Kirkpatrick D, Snoeyink J (1996) A compact piecewise-linear Voronoi diagram for convex sites in the plane. Discrete Comput Geom 15(1):73–105
Megiddo N (1983) Linear-time algorithms for linear programming in \(\text{ R}^{3}\) and related problems. SIAM J Comput 12(4):759–776
Megiddo N (1984) Linear programming in linear time when the dimension is fixed. J ACM 31(1):114–127
Munkers JR (2000) Topology, 2nd edn. Prentice Hall, London
Németh G, Kardos P, Palágyi K (2011) 2D parallel thinning and shrinking based on sufficient conditions for topology preservation. Acta Cybern 20(1):125–144
Németh G, Palágyi K (2011) Topology preserving parallel thinning algorithms. Int J Imaging Syst Technol 21(1):37–44
Preparata FP, Shamos MI (2012) Computational geometry: an introduction. Springer, Berlin
Prim RC (1957) Shortest connection networks and some generalizations. Bell Syst Tech J 36(6):1389–1401
Ronse C (1986) A Topological characterization of thinning. Theoret Comput Sci 43:31–41
Ronse C, Tajine M (2001) Hausdorff discretization for cellular distances and Its relation to cover and supercover discretizations. J Vis Comput Image Represent 12(2):169–200
Rosenfeld A (1970) Connectivity in digital pictures. J ACM 17(1):146–160
Rosenfeld A (1973) Arcs and curves in digital pictures. J ACM 20(1):81–87
Saha PK, Borgefors G, Sanniti di Baja G (2016) A survey on skeletonization algorithms and their applications. Pattern Recognit Lett 76:3–12
Stelldinger P (2008) Image digitization and its influence on shape properties in finite dimensions, vol 312. IOS Press, Amsterdam
Svensson S, Sanniti di Baja G (2003) Simplifying curve skeletons in volume images. Comput Vis Image Underst 90(3):242–257
Tajine M, Ronse C (2002) Topological properties of hausdorff discretization, and comparison to other discretization schemes. Theoret Comput Sci 283(1):243–268
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Brimkov, B., Brimkov, V.E. Optimal conditions for connectedness of discretized sets. J Comb Optim 43, 1493–1506 (2022). https://doi.org/10.1007/s10878-020-00691-0
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DOI: https://doi.org/10.1007/s10878-020-00691-0