Computers and Geosciences, Feb, 2012, Vol.39, p.50(14)
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cageo.2011.06.010 Byline: Ndeye Fatou Ngom (a), Olivier Monga (b), Mohamed Mahmoud Ould Mohamed (c), Patricia Garnier (d) Abstract: This paper focuses on the modeling of soil microstructures using generalized cylinders, with a specific application to pore space. The geometric modeling of these microstructures is a recent area of study, made possible by the improved performance of computed tomography techniques. X-scanners provide very-high-resolution 3D volume images (3-5[mu]m) of soil samples in which pore spaces can be extracted by thresholding. However, in most cases, the pore space defines a complex volume shape that cannot be approximated using simple analytical functions. We propose representing this shape using a compact, stable, and robust piecewise approximation by means of generalized cylinders. This intrinsic shape representation conserves its topological and geometric properties. Our algorithm includes three main processing stages. The first stage consists in describing the volume shape using a minimum number of balls included within the shape, such that their union recovers the shape skeleton. The second stage involves the optimum extraction of simply connected chains of balls. The final stage copes with the approximation of each simply optimal chain using generalized cylinders: circular generalized cylinders, tori, cylinders, and truncated cones. This technique was applied to several data sets formed by real volume computed tomography soil samples. It was possible to demonstrate that our geometric representation supplied a good approximation of the pore space. We also stress the compactness and robustness of this method with respect to any changes affecting the initial data, as well as its coherence with the intuitive notion of pores. During future studies, this geometric pore space representation will be used to simulate biological dynamics. Author Affiliation: (a) UCAD, UMI 209 UMMISCO, BP 1386, CP 18524, Dakar, Senegal (b) IRD, UMI 209 UMMISCO, BP 1386, CP 18524, Dakar, Senegal (c) Universite Pierre et Marie Curie, UMMISCO, France (d) INRA, UMR 1091 EGC, BP 01, F-78850 Thiverval-Grignon, France Article History: Received 30 August 2010; Revised 31 May 2011; Accepted 15 June 2011
Algorithms -- Analysis
Cengage Learning, Inc.