Results 1  10
of
110
A Survey on Shape Correspondence
, 2010
"... We present a review of the correspondence problem and its solution methods, targeting the computer graphics audience. With this goal in mind, we focus on the correspondence of geometric shapes represented by point sets, contours or triangle meshes. This survey is motivated by recent developments in ..."
Abstract

Cited by 75 (8 self)
 Add to MetaCart
We present a review of the correspondence problem and its solution methods, targeting the computer graphics audience. With this goal in mind, we focus on the correspondence of geometric shapes represented by point sets, contours or triangle meshes. This survey is motivated by recent developments in the field such as those requiring the correspondence of nonrigid or timevarying surfaces and a recent trend towards semantic shape analysis, of which shape correspondence is one of the central tasks. Establishing a meaningful shape correspondence is a difficult problem since it typically relies on an understanding of the structure of the shapes in question at both a local and global level, and sometimes also the shapes ’ functionality. However, despite its inherent complexity, shape correspondence is a recurrent problem and an essential component in numerous geometry processing applications. In this report, we discuss the different forms of the correspondence problem and review the main solution methods, aided by several classification criteria which can be used by the reader to objectively compare the methods. We finalize the report by discussing open problems and future perspectives.
Curve Skeleton Extraction from Incomplete Point Cloud
, 2009
"... We present an algorithm for curve skeleton extraction from imperfect point clouds where large portions of the data may be missing. Our construction is primarily based on a novel notion of generalized rotational symmetry axis (ROSA) of an oriented point set. Specifically, given a subset S of orient ..."
Abstract

Cited by 42 (10 self)
 Add to MetaCart
We present an algorithm for curve skeleton extraction from imperfect point clouds where large portions of the data may be missing. Our construction is primarily based on a novel notion of generalized rotational symmetry axis (ROSA) of an oriented point set. Specifically, given a subset S of oriented points, we introduce a variational definition for an oriented point that is most rotationally symmetric with respect to S. Our formulation effectively utilizes normal information to compensate for the missing data and leads to robust curve skeleton computation over regions of a shape that are generally cylindrical. We present an iterative algorithm via planar cuts to compute the ROSA of a point cloud. This is complemented by special handling of noncylindrical joint regions to obtain a centered, topologically clean, and complete 1D skeleton. We demonstrate that quality curve skeletons can be extracted from a variety of shapes captured by incomplete point clouds. Finally, we show how our algorithm assists in shape completion under these challenges by developing a skeletondriven point cloud completion scheme.
Automatic reconstruction of tree skeletal structures from point clouds
 ACM TRANS. ON GRAPH
, 2010
"... Trees, bushes, and other plants are ubiquitous in urban environments, and realistic models of trees can add a great deal of realism to a digital urban scene. There has been much research on modeling tree structures, but limited work on reconstructing the geometry of realworld trees – even then, m ..."
Abstract

Cited by 23 (2 self)
 Add to MetaCart
Trees, bushes, and other plants are ubiquitous in urban environments, and realistic models of trees can add a great deal of realism to a digital urban scene. There has been much research on modeling tree structures, but limited work on reconstructing the geometry of realworld trees – even then, most works have focused on reconstruction from photographs aided by significant user interaction. In this paper, we perform active laser scanning of realworld vegetation and present an automatic approach that robustly reconstructs skeletal structures of trees, from which full geometry can be generated. The core of our method is a series of global optimizations that fit skeletal structures to the often sparse, incomplete, and noisy point data. A significant benefit of our approach is its ability to reconstruct multiple overlapping trees simultaneously without segmentation. We demonstrate the effectiveness and robustness of our approach on many raw scans of different tree varieties.
COHENOR D.: A partaware surface metric for shape analysis
 Computer Graphics Forum (Special Issue of Eurographics
"... The notion of parts in a shape plays an important role in many geometry problems, including segmentation, correspondence, recognition, editing, and animation. As the fundamental geometric representation of 3D objects in computer graphics is surfacebased, solutions of many such problems utilize a su ..."
Abstract

Cited by 19 (4 self)
 Add to MetaCart
(Show Context)
The notion of parts in a shape plays an important role in many geometry problems, including segmentation, correspondence, recognition, editing, and animation. As the fundamental geometric representation of 3D objects in computer graphics is surfacebased, solutions of many such problems utilize a surface metric, a distance function defined over pairs of points on the surface, to assist shape analysis and understanding. The main contribution of our work is to bring together these two fundamental concepts: shape parts and surface metric. Specifically, we develop a surface metric that is partaware. To encode part information at a point on a shape, we model its volumetric context – called the volumetric shape image (VSI) – inside the shape’s enclosed volume, to capture relevant visibility information. We then define the partaware metric by combining an appropriate VSI distance with geodesic distance and normal variation. We show how the volumetric view on part separation addresses certain limitations of the surface view, which relies on concavity measures over a surface as implied by the wellknown minima rule. We demonstrate how the new metric can be effectively utilized in various applications including mesh segmentation, shape registration, partaware sampling and shape retrieval.
Computing multiscale curve and surface skeletons of genus 0 shapes using a global importance measure
 IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS
"... We present a practical algorithm for computing robust, multiscale curve and surface skeletons of 3D objects of genus zero. Based on a model which follows an advection principle, we assign to each point on the skeleton a part of the object surface, called the collapse. The size of the collapse is us ..."
Abstract

Cited by 18 (8 self)
 Add to MetaCart
We present a practical algorithm for computing robust, multiscale curve and surface skeletons of 3D objects of genus zero. Based on a model which follows an advection principle, we assign to each point on the skeleton a part of the object surface, called the collapse. The size of the collapse is used as a uniform importance measure for the curve and surface skeleton, so that both can be simplified by imposing a single threshold on this intuitive measure. The simplified skeletons are connected by default, without special precautions, due to the monotonicity of the importance measure. The skeletons possess additional desirable properties: They are centered, robust to noise, hierarchical, and provide a natural skeletontoboundary mapping. We present a voxelbased algorithm that is straightforward to implement and simple to use. We illustrate our method on several realistic 3D objects.
Variational Curve Skeletons Using Gradient Vector Flow
, 2008
"... Representing a 3D shape by a set of onedimensional curves that are locally symmetric with respect to its boundary (i.e., curve skeletons) is of importance in several machine intelligence tasks. This paper presents a fast, automatic, and robust variational framework for computing continuous, subvox ..."
Abstract

Cited by 17 (0 self)
 Add to MetaCart
Representing a 3D shape by a set of onedimensional curves that are locally symmetric with respect to its boundary (i.e., curve skeletons) is of importance in several machine intelligence tasks. This paper presents a fast, automatic, and robust variational framework for computing continuous, subvoxel accurate curve skeletons from volumetric objects. A reference point inside the object is considered a point source that transmits two wave fronts of different energies. The first front (βfront) converts the object into a graph, from which the object salient topological nodes are determined. Curve skeletons are tracked from those nodes along the cost field constructed by the second front (αfront) until the point source is reached. The accuracy and robustness of the proposed work are validated against competing techniques as well as a database of 3D objects. Unlike other stateoftheart techniques, the proposed framework is highly robust because it avoids locating and classifying skeletal junction nodes, employs a new energy that does not form medial surfaces, and finally extracts curve skeletons that correspond to the most prominent parts of the shape, and are hence less sensitive to noise.
Analysis, Reconstruction and Manipulation using Arterial Snakes
"... metal stool scanned pointset skeletal snakes arterial snake network edited model Figure 1: Starting from a noisy raw scan with large parts missing our algorithm analyzes and extracts a curve network with associated crosssectional profiles providing a reconstructed model. The extracted highlevel sh ..."
Abstract

Cited by 17 (7 self)
 Add to MetaCart
metal stool scanned pointset skeletal snakes arterial snake network edited model Figure 1: Starting from a noisy raw scan with large parts missing our algorithm analyzes and extracts a curve network with associated crosssectional profiles providing a reconstructed model. The extracted highlevel shape representation enables easy, intuitive, yet powerful geometry editing. Note that our algorithm is targeted towards delicate 1D features and fails to detect the small disc at the top of the stool. Manmade objects often consist of detailed and interleaving structures, which are created using cane, coils, metal wires, rods, etc. The delicate structures, although manufactured using simple procedures, are challenging to scan and reconstruct. We observe that such structures are inherently 1D, and hence are naturally represented using an arrangement of generating curves. We refer to the resultant surfaces as arterial surfaces. In this paper we approach for analyzing, reconstructing, and manipulating such arterial surfaces. ∗ Corresponding authors:
SkelTre: Robust skeleton extraction from imperfect point clouds
 VIS. COMPUT
, 2010
"... Terrestrial laser scanners capture 3D geometry of real world objects as a point cloud. This paper reports on a new algorithm developed for the skeletonization of a laser scanner point cloud. The skeletonization algorithm proposed in this paper consists of three steps: (i) extraction of a graph from ..."
Abstract

Cited by 15 (0 self)
 Add to MetaCart
Terrestrial laser scanners capture 3D geometry of real world objects as a point cloud. This paper reports on a new algorithm developed for the skeletonization of a laser scanner point cloud. The skeletonization algorithm proposed in this paper consists of three steps: (i) extraction of a graph from an octree organization, (ii) reduction of the graph to a skeleton, and (iii) embedding of the skeleton into the point cloud. For these three steps, only one input parameter is required. The results are validated on laser scanner point clouds representing 2 classes of objects; first on botanic trees as a special application and secondly on popular arbitrary objects. The presented skeleton found its first application in obtaining botanic tree parameters like length and diameter of branches and is presented here in a new, generalized version. Its definition as Reeb Graph, proofs the usefulness of the skeleton for applications like shape analysis. In this paper we show that the resulting skeleton contains the Reeb Graph and investigate the practically relevant parameters: centeredness and topological correctness. The robustness of this skeletonization method against undersampling, varying point density and systematic errors of the point cloud is demonstrated on real data examples.
L1Medial Skeleton of Point Cloud
"... We introduce L1medial skeleton as a curve skeleton representation for 3D point cloud data. The L1median is wellknown as a robust global center of an arbitrary set of points. We make the key observation that adapting L1medians locally to a point set representing a 3D shape gives rise to a onedim ..."
Abstract

Cited by 14 (4 self)
 Add to MetaCart
We introduce L1medial skeleton as a curve skeleton representation for 3D point cloud data. The L1median is wellknown as a robust global center of an arbitrary set of points. We make the key observation that adapting L1medians locally to a point set representing a 3D shape gives rise to a onedimensional structure, which can be seen as a localized center of the shape. The primary advantage of our approach is that it does not place strong requirements on the quality of the input point cloud nor on the geometry or topology of the captured shape. We develop a L1medial skeleton construction algorithm, which can be directly applied to an unoriented raw point scan with significant noise, outliers, and large areas of missing data. We demonstrate L1medial skeletons extracted from raw scans of a variety of shapes, including those modeling highgenus 3D objects, plantlike structures, and curve networks.
Point cloud skeletons via laplacianbased contraction
 In Proc. Conf. on Shape Modeling and Appl
, 2010
"... Abstract—We present an algorithm for curve skeleton extraction via Laplacianbased contraction. Our algorithm can be applied to surfaces with boundaries, polygon soups, and point clouds. We develop a contraction operation that is designed to work on generalized discrete geometry data, particularly p ..."
Abstract

Cited by 14 (3 self)
 Add to MetaCart
(Show Context)
Abstract—We present an algorithm for curve skeleton extraction via Laplacianbased contraction. Our algorithm can be applied to surfaces with boundaries, polygon soups, and point clouds. We develop a contraction operation that is designed to work on generalized discrete geometry data, particularly point clouds, via local Delaunay triangulation and topological thinning. Our approach is robust to noise and can handle moderate amounts of missing data, allowing skeletonbased manipulation of point clouds without explicit surface reconstruction. By avoiding explicit reconstruction, we are able to perform skeletondriven topology repair of acquired point clouds in the presence of large amounts of missing data. In such cases, automatic surface reconstruction schemes tend to produce incorrect surface topology. We show that the curve skeletons we extract provide an intuitive and easytomanipulate structure for effective topology modification, leading to more faithful surface reconstruction. Keywordscurve skeleton; point cloud; Laplacian; contraction; topology repair; surface reconstruction I.