We describe an automatic surface reconstruction technique from a set of planar data points organised in parallel sections. The reconstruction employs skeletal implicit surfaces. Two key points in this study are: Calculation of the 3D skeleton by establishing a correspondence between each pair of 2D Voronoi skeleton of two neighbouring sections, Use of a uniform field function necessitating the ...

Robust and time-efficient skeletonization of a (planar) shape, which is connectivity preserving and based on Euclidean metrics, can be achieved by first regularizing the Voronoi diagram (VD) of a shape’s boundary points, i.e., by removal of noise-sensitive parts of the tessellation and then by establishing a hierarchic organization of skeleton constituents . Each component of the VD is attribut...

We consider the convex polytope x(x) that consists of those n X n (row) stochastic matrices having a common nonnegative (left) fixed vector rt. We examine the l-skeleton of d(x) and show how to construct all extreme points adjacent to a given one (as vertices of the l-skeleton). Connections with transportation polytopes are discussed. Further, we give a formula for the degree of an extreme poin...

Trust-aware recommender system (TARS) recommends ratings based on user trust. It greatly improves the conventional collaborative filtering by providing reliable recommendations when dealing with the data sparseness problem. One basic research issue of TARS is to improve the recommending efficiency, in which the key point is to find sufficient number of recommenders efficiently for active users....

Shape skeletons are fundamental concepts for describing the shape of geometric objects, and have found a variety of applications in a number of areas where geometry plays an important role. Two types of skeletons commonly used in geometric computations are the straight skeleton of a (linear) polygon, and the medial axis of a bounded set of points in the k-dimensional Euclidean space. However, e...

This papor dcsc.ribcs a new hair repre.sentation techiiiqiui for drawing 3D CG characters. In our approach liair models are representcid by skeleton-based implicit surfaces. Implicit inodoliiig allow.s ropresiuitlng union and division of wisp.s of hair by n.sing a blobby model. Our method gets hair skele tons as input data. The skeleton is interpolated using a spline function and then implicit ...

Skeletal representations of shape have attracted enormous interest ever since their introduction by Blum [Blum H (1973) J Theor Biol 38:205-287], because of their potential to provide a compact, but meaningful, shape representation, suitable for both neural modeling and computational applications. But effective computation of the shape skeleton remains a notorious unsolved problem; existing app...

We consider the problem of learning a causal graph over a set of variables with interventions. We study the cost-optimal causal graph learning problem: For a given skeleton (undirected version of the causal graph), design the set of interventions with minimum total cost, that can uniquely identify any causal graph with the given skeleton. We show that this problem is solvable in polynomial time...

Tooth segmentation has an important role in computer-aided orthodontics. However, fine segmentation results remain difficult to obtain because of various tooth shapes, complex tooth arrangements, and especially, tooth-crowding problems. Most published approaches or commercial solutions in this area are either interaction-intensive or inaccurate, and thus, we propose a novel tooth segmentation a...

In this paper, we introduce a generalized morphological skeleton transform that uses eight structuring elements to generate skeleton subsets. The number of representative points needed to represent a given shape is significantly lower than in the standard skeleton transform. A collection of shape components needed to build a structural representation is easily selected from the shape elements g...