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Thinning on binary images is an iterative layer by layer erosion until only the " skeletons " of the objects are left. This paper presents an efficient parallel thinning algorithm which produces either curve skeletons or surface skeletons from 3D binary objects. It is important that a curve skeleton is extracted directly (i.e., without creating a surface(More)
Thinning is a frequently used method for extracting skeletons in discrete spaces. This paper presents an efficient parallel Ž thinning algorithm that directly extracts medial lines from elongated 3D binary objects i.e., without creating medial. surface. Our algorithm provides good results, preserves topology and it is easy to implement. q 1998 Elsevier(More)
Skeleton is a frequently applied shape feature to represent the general form of an object. Thinning is an iterative object reduction technique for producing a reasonable approximation to the skeleton in a topology preserving way. This paper describes a sequential 3D thinning algorithm for extracting medial lines of objects in (26, 6) pictures. Our algorithm(More)
  • S Brunetti, A Del Lungo, F Del Ristoro, A Kuba, M Nivat
  • 2000
In this paper we examine the problem of reconstructing a discrete two-dimensional set from its two orthogonal projection (H, V) when the set satisfies some convexity conditions. We show that the algorithm of the paper [Int. J. Imaging Systems and Technol. 9 (1998) 69] is a good heuristic algorithm but it does not solve the problem for all (H, V) instances.(More)
The reconstruction of 8-connected but not 4-connected hv-convex discrete sets from few projections is considered. An algorithm is given with worst case complexity of O(mn min{m, n}) to reconstruct all sets with given horizontal and vertical projections. Experimental results are also presented. It is shown, that using also the diagonal projections the(More)
The reconstruction problem is considered in those classes of discrete sets where the reconstruction can be performed from two projections in polynomial time. The reconstruction algorithms and complexity results are summarized in the case of hv-convex sets, hv-convex 8-connected sets, hv-convex polyominoes, and directed h-convex sets. As new results some(More)
Discrete tomography concerns the reconstruction of functions with a finite number of values from few projections. For a number of important real-world problems, this tomography problem involves thousands of variables. Applicability and performance of discrete tomography therefore largely depend on the criteria used for reconstruction and the optimization(More)
We present two approaches for automatically segmenting the spinal cord/canal from native CT images of the thorax region containing the spine. Different strategies are included to handle images where only part of the spinal column is visible. The algorithms require one seed point given on a slice located in the middle region of the spine, and the rest is(More)