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25
Range Image Segmentation by an Effective JumpDiffusion Method
 IEEE Transactions on Pattern Analysis and Machine Intelligence
, 2004
"... Abstract—This paper presents an effective jumpdiffusion method for segmenting a range image and its associated reflectance image in the Bayesian framework. The algorithm works on complex realworld scenes (indoor and outdoor), which consist of an unknown number of objects (or surfaces) of various s ..."
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Cited by 25 (1 self)
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Abstract—This paper presents an effective jumpdiffusion method for segmenting a range image and its associated reflectance image in the Bayesian framework. The algorithm works on complex realworld scenes (indoor and outdoor), which consist of an unknown number of objects (or surfaces) of various sizes and types, such as planes, conics, smooth surfaces, and cluttered objects (like trees and bushes). Formulated in the Bayesian framework, the posterior probability is distributed over a solution space with a countable number of subspaces of varying dimensions. The algorithm simulates Markov chains with both reversible jumps and stochastic diffusions to traverse the solution space. The reversible jumps realize the moves between subspaces of different dimensions, such as switching surface models and changing the number of objects. The stochastic Langevin equation realizes diffusions within each subspace. To achieve effective computation, the algorithm precomputes some importance proposal probabilities over multiple scales through Hough transforms, edge detection, and data clustering. The latter are used by the Markov chains for fast mixing. The algorithm is tested on 100 1D simulated data sets for performance analysis on both accuracy and speed. Then, the algorithm is applied to three data sets of range images under the same parameter setting. The results are satisfactory in comparison with manual segmentations.
Creating solid models from single 2D sketches
, 1995
"... We describe a method of constructing a Brep solid model from a single hiddenline removed sketch view of a 3D object. The main steps of our approach are as follows. The sketch is first tidied in 2D (to remove digitisation errors). Line labelling is used to deduce the initial topology of the object ..."
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Cited by 19 (4 self)
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We describe a method of constructing a Brep solid model from a single hiddenline removed sketch view of a 3D object. The main steps of our approach are as follows. The sketch is first tidied in 2D (to remove digitisation errors). Line labelling is used to deduce the initial topology of the object and to locate hidden faces. Constraints are then produced from the line labelling and features in the drawing (such as probable symmetry) involving the unknown face coefficients and point depths. A least squares solution is found to the linear system and any grossly incompatible equations are rejected. Vertices are recalculated as the intersections of the faces to ensure we have a reconstructible solid. Any incomplete faces are then completed as far as possible from neighbouring faces, producing a solid model from the initial sketch, if successful. The current software works for polyhedral objects with trihedral vertices.
Automatic Creation of BoundaryRepresentation Models from Single Line Drawings
, 2002
"... This thesis presents methods for the automatic creation of boundaryrepresentation models of polyhedral objects from single line drawings depicting the objects. This topic is important in that automated interpretation of freehand sketches would remove a bottleneck in current engineering design metho ..."
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Cited by 17 (11 self)
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This thesis presents methods for the automatic creation of boundaryrepresentation models of polyhedral objects from single line drawings depicting the objects. This topic is important in that automated interpretation of freehand sketches would remove a bottleneck in current engineering design methods. The thesis does not consider conversion of freehand sketches to line drawings or methods which require manual intervention or multiple drawings. Thge thesis contains a number of...
Estimating Depth from Line Drawings
 SM'02
, 2002
"... ... line drawing of an engineering object (with hidden lines removed) as a Brep model. As part of this process, we seek to deduce a frontal geometry of the object, a 3D geometric realisation of that part of the object visible in the drawing. Inflation takes a drawing in which all lines have been li ..."
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Cited by 12 (5 self)
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... line drawing of an engineering object (with hidden lines removed) as a Brep model. As part of this process, we seek to deduce a frontal geometry of the object, a 3D geometric realisation of that part of the object visible in the drawing. Inflation takes a drawing in which all lines have been linelabelled, and creates the frontal geometry by adding a zcoordinate to the x and ycoordinates of each junction. This depth information comes from compliance functions, interpretations of drawing features expressed as equations in junction zcoordinates. We examine several compliance functions, and assessing their use in interpretation of engineering objects. We also describe a compliance function based on junction labels, and remove its previous restriction to trihedral vertices. We give a
A System for Constructing Boundary Representation Solid Models from a TwoDimensional Sketch
, 2000
"... sketch with hidden lines removed of a single polyhedral object into a boundary representation solid model. ..."
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Cited by 8 (1 self)
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sketch with hidden lines removed of a single polyhedral object into a boundary representation solid model.
Understanding Engineering Drawings: A Survey
 In Proceedings of First IARP Workshop on Graphics Recognition
, 1995
"... Mechanical design and manufacturing information for 3D solid objects has been effectively conveyed through a set of annotated orthographic projections and optional crosssections. This forms the basis of engineering drawings, which solve the problem of unambiguously representing a 3D object on a 2 ..."
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Cited by 8 (0 self)
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Mechanical design and manufacturing information for 3D solid objects has been effectively conveyed through a set of annotated orthographic projections and optional crosssections. This forms the basis of engineering drawings, which solve the problem of unambiguously representing a 3D object on a 2D plane. In this paper we address the inverse problem: given an engineering drawing of an object, construct the object's 3D representation. To enable automatic recognition, the paper line drawings are initially scanned, and yield images which are inherently noisy. The 3D objects themselves can have surfaces that are planar, spherical, or cylindrical. We examine the stages of drawing generation and formulate the drawing interpretation problem. Most 3D reconstruction algorithms have assumed that the vertex coordinates and line and arc endpoint coordinates are known accurately and without error, and that no annotation exists in the drawing. In practice, however, scanned drawings are noisy a...
Frontal Geometry from Sketches of Engineering Objects:Is Line Labelling Necessary?
 UNIVERSITY OF WISCONSIN
, 1990
"... A tool which can quickly interpret line drawings (with hidden lines removed) of engineering objects as boundary representation CAD models would be of significant benefit in the process of engineering design. Inflation of the drawing to produce a frontal geometry, a geometric realisation of that par ..."
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Cited by 8 (5 self)
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A tool which can quickly interpret line drawings (with hidden lines removed) of engineering objects as boundary representation CAD models would be of significant benefit in the process of engineering design. Inflation of the drawing to produce a frontal geometry, a geometric realisation of that part of the object visible in the drawing, is an important stage of this process. Previous
Recovering occlusion boundaries from an image
 In ICCV
, 2007
"... Occlusion reasoning is a fundamental problem in computer vision. In this paper, we propose an algorithm to recover the occlusion boundaries and depth ordering of freestanding structures in the scene. Rather than viewing the problem as one of pure image processing, our approach employs cues from an ..."
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Cited by 7 (3 self)
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Occlusion reasoning is a fundamental problem in computer vision. In this paper, we propose an algorithm to recover the occlusion boundaries and depth ordering of freestanding structures in the scene. Rather than viewing the problem as one of pure image processing, our approach employs cues from an estimated surface layout and applies Gestalt grouping principles using a conditional random field (CRF) model. We propose a hierarchical segmentation process, based on agglomerative merging, that reestimates boundary strength as the segmentation progresses. Our experiments on the Geometric Context dataset validate our choices for features, our iterative refinement of classifiers, and our CRF model. In experiments on the Berkeley Segmentation Dataset, PASCAL VOC 2008, and LabelMe, we also show that the trained algorithm generalizes to other datasets and can be used as an object boundary predictor with figure/ground labels. 1.
Geometrical Reconstruction From Single Line Drawings Using OptimizationBased Approaches
 WSCG’99. Conference proceedings, edited by Vaclav Skala (ISBN 8070824905), Volume II
, 1999
"... Optimization is one of the most promising geometrical reconstruction approaches. In this approach, the 2D vertices of the given figure maintain their plane coordinates (X,Y), while a set of Z coordinates (orthogonal to the plane) is computed to obtain a 3D configuration that matches the "implicit ..."
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Cited by 6 (3 self)
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Optimization is one of the most promising geometrical reconstruction approaches. In this approach, the 2D vertices of the given figure maintain their plane coordinates (X,Y), while a set of Z coordinates (orthogonal to the plane) is computed to obtain a 3D configuration that matches the "implicit spatial information" contained in the departure drawing. In other words, Z coordinates are the variables, and image regularities are used to define both the Objective Function and the Constraints. Some authors have introduced and tested the approach. Nevertheless, further improvements are needed. Mainly because in this problem only global optimum is acceptable in order to ensure the "psychologically plausible" model is always the one to be obtained. In this paper, some key aspects of the strategy proposed by the authors to convey the optimization process towards the psychologically plausible solution are discussed. Keywords: geometrical reconstruction, optimization. 1 This work wa...
Modeling Image Analysis Problems Using Markov Random Fields
, 2000
"... this article are addressed mainly from the computational viewpoint. The primary concerns are how to dene an objective function for the optimal solution for an image analysis problem and how to nd the optimal solution. The reason for dening the solution in an optimization sense is due to various unce ..."
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Cited by 6 (1 self)
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this article are addressed mainly from the computational viewpoint. The primary concerns are how to dene an objective function for the optimal solution for an image analysis problem and how to nd the optimal solution. The reason for dening the solution in an optimization sense is due to various uncertainties in imaging processes. It may be dicult to nd the perfect solution, so we usually look for an optimal one in the sense that an objective, into which constraints are encoded, is optimized