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2. Oliver van Kaick,
Hao Zhang,
Ghassan Hamarneh,
Daniel Cohen-Or,
"A Survey on Shape Correspondence,"
Eurographics 2010 State-of-the-Art Report, TBA.
[PDF |
Slides |
bibtex]
We present a review of the correspondence problem targeted towards the computer graphics audience. This survey is motivated by recent developments such as advances in the correspondence of non-rigid or isometric shapes and methods that extract semantic information from the shapes ...
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1. Qian Zheng,
Andrei Sharf,
Andrea
Tagliasacchi, Baoquan Chen, Hao Zhang,
Alla Sheffer,
Daniel Cohen-Or,
"Consensus Skeleton for Non-Rigid Space-Time Registration,"
Computer Graphics Forum (Proceeding of Eurographics 2010), to appear.
[PDF |
Slides |
bibtex]
We introduce the notion of consensus skeletons for non-rigid space-time registration of a deforming shape. Instead of basing the registration on point features, which are local and sensitive to noise, we adopt the curve skeleton of the shape as a global and descriptive feature for the task. Our method uses no template and only assumes that the skeletal structure of the captured shape remains largely consistent over time ...
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12. Kai Xu,
Hao Zhang,
Andrea Tagliasacchi,
Ligang Liu,
Guo Li, Min Meng, and Yueshan Xiong,
"Partial Intrinsic Reflectional Symmetry of 3D Shapes,"
ACM Trans. on Graphics (Proceeding of SIGGRAPH Asia 2009),
Article 138.
[PDF (16 MB) |
PDF (reduced size: 7 MB) |
Project
page | Slides (15 MB) |
bibtex]
While many 3D objects around us exhibit various forms of global symmetries, prominent intrinsic symmetries which exist only on parts of an object are also well recognized ... In this paper, we introduce algorithms to extract and utilize partial intrinsic reflectional symmetries (PIRS) of a 3D shape ...
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11. Hui Huang, Dan Li,
Hao Zhang,
Uri Ascher, and
Daniel Cohen-Or,
"Consolidation of Unorganized Point Clouds for Surface Reconstruction,"
ACM Trans. on Graphics (Proceeding of SIGGRAPH Asia 2009), Article 176.
[PDF (8 MB) |
PDF (reduced size: 2 MB)
| Slides (7 MB) |
Project
page with source code |
bibtex]
We consolidate an unorganized point cloud with noise, outliers, non-uniformities, and interference between close-by surface sheets as a preprocess to surface generation ... First, we present a weighted locally optimal projection operator ... Next, we introduce an iterative framework for robust normal estimation, ...
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10. Kai Xu,
Daniel Cohen-Or,
Tao Ju,
Ligang Liu,
Hao Zhang,
Shizhe Zhou, and
Yueshan Xiong,
"Feature-Aligned Shape Texturing,"
ACM Trans. on Graphics (Proceeding of SIGGRAPH Asia 2009), Article 108.
[PDF (20 MB) |
PDF (reduced size: 10 MB)
| Slides (19 MB) |
Project
page |
Source Code |
bibtex]
We explore the use of salient curves in synthesizing natural-looking, shape-revealing textures on surfaces. Our synthesis is guided by two principles: matching the direction of the texture patterns to those of the salient curves, and aligning the prominent feature lines in the texture to the salient curves exactly ...
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9. Lior Shapira,
Shy Shalom,
Ariel Shamir,
Daniel Cohen-Or, and
Hao Zhang,
"Contextual Part Analogies in 3D Objects,"
International Journal of Computer Vision (Spectial Issue on 3D Object Retrieval),
2009, DOI 10.1007/s11263-009-0279-0.
[PDF |
bibtex]
We address the problem of finding analogies between parts of 3D objects. By partitioning an object into meaningful parts and finding analogous parts in other objects, not necessarily of the same type, based on a contextual signature, many analysis and modeling tasks could be enhanced ...
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8. Ramsay Dyer,
Hao Zhang, and
Torsten Moeller,
"Gabriel meshes and Delaunay edge flips,"
Proc. of SIAM/ACM Joint Conf. on Geometric and Physical Modeling (GPM),
to appear as poster paper, 2009.
[PDF |
extended
version with more proofs |
bibtex]
We undertake a study of the local properties of 2-Gabriel meshes. We show that, under mild constraints on the dihedral angles, such meshes are Delaunay meshes. The analysis is done by means of the Delaunay edge flipping algorithm and it reveals the details of the distinction between these two mesh structures ...
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7. Andrea
Tagliasacchi,
Hao Zhang, and
Daniel Cohen-Or,
"Curve Skeleton Extraction from Incomplete Point Cloud,"
ACM Trans. on Graphics (Proceeding of SIGGRAPH 2009), Volume 28, Number 3,
Article 71, 9 pages, DOI = 10.1145/1531326.1531377.
[PDF |
Project page | bibtex]
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 a point set with normals, via a variational formulation ...
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6. Kai Xu,
Hao Zhang,
Daniel Cohen-Or, and Yueshan Xiong,
"Dynamic Harmonic Fields for Surface Processing,"
Computers and Graphics (Special Issue of Shape Modeling
International 2009), Vol. 33, pp. 391-398, 2009.
[PDF |
Video |
bibtex]
We propose a method for fast updating of harmonic fields defined on polygonal meshes, enabling real-time insertion and deletion of constraints. Our approach utilizes the penalty method to enforce constraints in harmonic field computation. It maintains the symmetry of the Laplacian system ...
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5. Xiaoxing Li,
Tao Jia, and
Hao Zhang,
"Expression-Insensitive 3D Face Recognition using Sparse
Representation,"
IEEE CS Conf. on Computer Vision and Pattern Recognition (CVPR
2009), to
appear.
[PDF |
bibtex]
We present a face recognition method based on sparse representation for recognizing 3D face meshes under expressions using low-level geometric features ... To handle facial expressions, we design a feature pooling and ranking scheme to collect various types of low-level geometric features and rank them ...
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4. Hao Zhang,
Oliver van Kaick,
and Ramsay Dyer,
"Spectral Mesh Processing," (revised and extended version
of Eurographics
2007 STAR report) Computer Graphics Forum, to appear.
[PDF |
bibtex]
We provide the first comprehensive survey on spectral mesh processing. Spectral methods for mesh processing and analysis rely on eigenvalues, eigenvectors, or eigenspace projections derived from appropriately defined mesh operators to carry out desired tasks ...
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3. Kai Xu,
Zhiquan Cheng,
Yanzhen Wang, Yueshan Xiong, and Hao Zhang,
"Quality Encoding for Tetrahedral Mesh Optimization,"
Computers and Graphics (Special Issue of Shape Modeling
International
2009), Vol. 33, pp. 250-261, 2009.
[PDF |
bibtex
]
We define quality differential coordinates (QDC) for per-vertex encoding of the quality of a tetrahedral mesh. Our formulation allows the incorporation of element quality metrics into QDC construction to penalize badly shaped and inverted tetrahedra ...
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2. Rong Liu,
Hao Zhang,
Ariel Shamir,
and
Daniel Cohen-Or,
"A Part-Aware Surface Metric for Shape Analysis,"
Computer Graphics Forum (Special Issue of Eurographics 2009),
Vol. 28, No. 2, 397-406, 2009.
[PDF |
bibtex]
The notion of parts in a shape plays an important role in many geometry problems. At the same time, many such problems utilize a surface metric to assist shape analysis and understanding. The main contribution of our work is to bring together these two fundamental concepts ...
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1. Matt Olson and
Hao Zhang,
"Tangential Distance Field for Mesh Silhouette
Analysis,," Computer Graphics Forum,
Vol. 28, No. 1, pp. 84-100, 2009.
[PDF |
bibtex]
We introduce a novel class of distance fields for a given surface defined by its tangent planes. At each point in space, we assign a scalar value which is a weighted sum of distances to these tangent planes. We use four applications to illustrate the benefit of using the resulting TDF scalar field: view point selection, ...
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3. Ramsay Dyer,
Hao Zhang, and
Torsten Moeller,
"Surface sampling and the intrinsic Voronoi diagram,"
Computer Graphics Forum
(Special Issue of Symposium of
Geometry Processing 2008), Volume 27, Number 5, pp. 1431-1439, 2008.
(won Best Paper Award at SGP)
[PDF |
Talk Slides |
bibtex]
We develop adaptive sampling criteria which guarantee a topologically faithful mesh and demonstrate an improvement and simplification over earlier results, albeit restricted to 2D surfaces. These sampling criteria are based on the strong convexity radius and the injectivity radius ...
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2. Hao Zhang,
Alla Sheffer,
Daniel Cohen-Or,
Qingnan Zhou,
Oliver van Kaick,
and
Andrea Tagliasacchi,
"Deformation-Drive Shape Correspondence,"
Computer Graphics Forum
(Special Issue of Symposium of
Geometry Processing 2008), Volume 27, Number 5, pp. 1393-1402, 2008.
[PDF |
Talk Slides |
bibtex |
Project page (UBC |
SFU)]
We present an automatic feature correspondence algorithm capable of handling large, non-rigid shape variations, as well as partial matching ... The search is deformation-driven, prioritized by a self-distortion energy measured on meshes deformed according to a given correspondence ...
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1. Rong Liu,
Hao Zhang, and James Busby,
"Convex Hull Covering of Polygonal Scenes for Accurate
Collision Detection in Games,"
Proc. of Graphics Interface 2008, pp. 203-210.
[PDF |
PDF Talk Slides |
bibtex]
We look at a particular instance of the convex decomposition problem which arises from real-world game development. Given a collection of polyhedral surfaces (possibly with boundaries, holes, and complex interior structures) that model the scene geometry in a game environment, we wish to find a small set of convex hulls ...
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8. Oliver van Kaick,
Ghassan Hamarneh,
Hao Zhang, and
Paul Wighton,
"Contour Correspondence via Ant Colony Optimization,"
Proc. of Pacific Graphics
2007, pp. 271-280.
[Oliver's page
with paper and MATLAB code |
bibtex]
We formulate contour correspondence as a Quadratic Assignment Problem (QAP), incorporating proximity information. By maintaining the neighborhood relation between points this way, we show that better matching results are obtained in practice. We propose the first Ant Colony Optimization (ACO) algorithm ...
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7. Ramsay Dyer,
Hao Zhang, and
Torsten Moeller,
"Delaunay Mesh Construction,"
Proc. of Eurographics Symposium on Geometry Processing (SGP)
2007, pp. 273-282.
[PDF |
PDF Talk Slides |
bibtex]
We present algorithms to produce Delaunay meshes from arbitrary triangle meshes by edge flipping and geometry-preserving refinement and prove their correctness. In particular we show that edge flipping serves to reduce mesh surface area, and that a poorly sampled input mesh may yield unflippable edges necessitating refinement ...
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6. Hao Zhang,
Oliver van Kaick,
and Ramsay Dyer,
"Spectral Methods for Mesh Processing and Analysis,"
Proc. of Eurographics
2007 State of the Art Report, pp. 1-22.
[PDF |
PDF Talk Slides |
bibtex]
Spectral methods for mesh processing and analysis rely on the eigenvalues, eigenvectors, or eigenspace projections derived from appropriately defined mesh operators to carry out desired tasks. This state-of-the-art report aims to provide a comprehensive survey on the spectral approach ...
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5. Rong Liu and Hao Zhang,
"Mesh Segmentation via Spectral Embedding and Contour
Analysis,"
Computer Graphics Forum (Special Issue of Eurographics 2007),
Vol. 26, pp. 385-394, 2007.
[PDF |
bibtex]
We propose a mesh segmentation algorithm where at each step, a sub-mesh embedded in 3D is first spectrally projected into the plane with a contour extracted from the planar embedding. Transforming the shape analysis problem to the 2D domain facilitates our segmentability analysis and sampling tasks ...
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4. Xiaoxing Li and Hao Zhang,
"Adapting Geometric Attributes for Expression-Invariant
3D Face Recognition,"
Proc. of Shape
Modeling International (SMI) 2007, pp. 21-32.
[PDF |
PDF Talk Slides |
bibtex]
We investigate the use of multiple intrinsic geometric attributes, including angles, geodesic distances, and curvatures, for 3D face recognition ... As invariance to facial expressions holds the key to improving recognition performance, we propose to train for the component-wise weights ...
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3. Ramsay Dyer,
Hao Zhang, and
Torsten Moeller,
"Voronoi-Delaunay Duality and Delaunay Meshes,"
Proc. of ACM
Symposium on Solid and Physical Modeling (SPM) 2007,
pp. 415-420.
[PDF |
bibtex]
We define a Delaunay mesh to be a manifold triangle mesh whose edges form an intrinsic Delaunay triangulation or iDT of its vertices ... We show that meshes constructed from a smooth surface by taking an iDT or a restricted Delaunay triangulation, do not in general yield a Delaunay mesh ...
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2. Varun Jain, Hao Zhang, and
Oliver van Kaick,
"Non-Rigid Spectral Correspondence of Triangle Meshes,"
International Journal on Shape Modeling
(via invitation to Special Issue of SMI 2006), Volume 13, Number 1,
pp. 101-124.
[PDF |
bibtex]
We present an algorithm for finding a meaningful correspondence between two triangle meshes, which is designed to handle general non-rigid transformations. Our algorithm operates on embeddings of the two shapes in the spectral domain so as to normalize them with respect to uniform scaling and rigid-body transformation.
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1. Varun Jain and Hao Zhang,
"A Spectral Approach to Shape-Based Retrieval of Articulated 3D
Models,"
Computer-Aided Design (via invitation to
Special
Issue of GMP 2006), Vol. 39, Issue 5, pp. 398-407, 2007.
[PDF |
DOI |
bibtex]
We present an approach for robust shape retrieval from databases containing articulated 3D models. Each shape is represented by the eigenvectors of an appropriately defined affinity matrix, forming a spectral embedding which achieves normalization against rigid-body transformations, shape articulation ...
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8. John Li and Hao Zhang,
"Nonobtuse Remeshing and Decimation,"
in Proceeding of Symposium on Geometry Processing (SGP) 2006
(short paper), pp.235-238.
[PDF |
PPT Talk Slides |
bibtex]
We propose an algorithm for guaranteed nonobtuse remeshing and nonobtuse mesh decimation. Our strategy for the remeshing problem is to first convert an input mesh, using a modified Marching Cubes algorithm, into a rough approximate mesh that is guaranteed to be nonobtuse. We then apply iterative "deform-to-fit" ...
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7. Matt Olson and
Hao Zhang,
"Silhouette Extraction in Hough Space,"
Computer Graphics Forum
(Special Issue on Eurographics 2006),
Volume 25, Number 3, pp. 273-282, 2006.
[PDF |
PDF Talk Slides |
bibtex]
We present an efficient silhouette extractor for triangle meshes under perspective projection in the Hough space. The more favorable point distribution in Hough space allows us to obtain significant performance gains over the traditional dual-space based techniques ...
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6. Varun Jain and Hao Zhang,
"Shape-Based Retrieval of Articulated 3D Models Using Spectral
Embeddings," in Proceeding of
Geometric Modeling and Processing 2006, pp. 295-308.
[PDF |
PPT Talk Slides |
bibtex]
We present a spectral approach for robust shape retrieval from databases containing articulated 3D shapes. We show absolute improvement in retrieval performance when conventional shape descriptors are used in the spectral domain on the McGill database of articulated 3D shapes. We also propose a simple eigenvalue-based descriptor ...
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5. Rong Liu, Hao Zhang, and
Oliver van Kaick,
"Spectral Sequencing based on Graph Distance,"
in Proceeding of
Geometric Modeling and Processing 2006 (poster paper), pp. 632-638.
[PDF |
PPT Poster |
bibtex]
In this paper, we treat optimal mesh layout generation as a problem of preserving graph distances and propose to use the subdominant eigenvector of a kernel (affinity) matrix for sequencing ...
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4. Rong Liu, Varun Jain,
and Hao Zhang,
"Subsampling for Efficient Spectral Mesh Processing,"
in Proceeding of Computer Graphics International 2006, Lecture Notes
in Computer Science 4035, H.-P. Seidel, T. Nishita, and Q. Peng,
Eds., pp. 172-184, 2006. (acceptance rate: 10%)
[PDF |
PPT Talk Slides |
bibtex]
We apply Nystrom method, a sub-sampling and reconstruction technique, to speed up spectral mesh processing. We first relate this method to Kernel Principal Component Analysis (KPCA). This enables us to derive a novel measure in the form of a matrix trace, based soly on sampled data, to quantify the quality of Nystrom approximation ...
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3. Varun Jain and Hao Zhang,
"Robust 3D Shape Correspondence in the Spectral Domain,"
in Proceeding of International Conference on Shape Modeling and
Applications
(SMI) 2006, pp. 118-129, 2006.
[PDF |
PPT Talk Slides |
bibtex]
We present an algorithm for finding a meaningful correspondence between two 3D shapes given as triangle meshes. Our algorithm operates on embeddings of the two shapes in the spectral domain so as to normalize them with respect to uniform scaling, rigid-body transformation and shape bending ...
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2. Andrew Clements and Hao Zhang,
"Minimum Ratio Contours on Surface Meshes,"
in Proceeding of International Conference on Shape Modeling and
Applications (SMI) 2006, pp. 26-37, 2006.
[PDF |
PPT Talk Slides |
bibtex]
We present a novel approach for discretely optimizing contours on the surface of a triangle mesh. This is achieved through the use of a minimum ratio cycle (MRC) algorithm, where we compute a contour having the minimal ratio between a novel contour energy term and the length of the contour ...
|
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1. Xiaoxing Li,
Greg Mori, and Hao Zhang,
"Expression-Invariant Face Recognition with Expression
Classification,"
in Proceeding of Canadian Conference on Computer and Robot Vision
(CRV) 2006, pp. 77-83, 2006.
[PDF |
PPT Poster |
bibtex]
Facial expression, which changes face geometry, usually has an adverse effect on the performance of a face recognition system. On the other hand, face geometry is a useful cue for recognition. Taking these into account, we utilize the idea of separating geometry and texture information in a face image ...
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9. Hao Zhang and Rong Liu,
"Mesh Segmentation via Recursive and Visually Salient Spectral
Cuts,"
in Proceeding of Vision, Modeling, and Visualization 2005,
pp. 429-436, 2005.
[PDF |
PDF Talk Slides |
bibtex]
|
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8. Varun Jain and Hao Zhang,
"Robust 2D Shape Correspondence using Geodesic Shape
Context,"
in Proceeding of Pacific Graphics 2005, (short paper), pp.
121-124, 2005.
[bibtex]
|
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7. Hao Zhang,
"Discrete Combinatorial Laplacian Operators for Digital Geometry
Processing,"
in Proc. of SIAM Conference on Geometric Design and
Computing,
pp. 575-592, 2004.
[PDF |
bibtex]
|
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6. Rong Liu and Hao Zhang,
"Segmentation of 3D Meshes through Spectral Clustering,"
in Proceeding of Pacific Graphics 2004, pp. 298-305.
[PDF |
PDF Talk Slides |
bibtex]
|
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5. Hao Zhang and Hendrik C. Blok,
"Optimal Mesh Signal Transforms,"
in Proceeding of IEEE Geometric Modeling and Processing
2004 (poster paper), pp. 373-379.
[bibtex]
|
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4. Hao Zhang and
Eugene Fiume,
"Butterworth Filtering and Implicit Fairing of Irregular
Meshes,"
in Proceedings of Pacific Graphics 2003 (short paper),
pp. 502-506.
[bibtex]
|
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3. Hao Zhang and
Eugene Fiume,
"Mesh Smoothing with Shape or Feature Preservation,"
in Advances in Modeling, Animation, and Rendering,
J. Vince and R. Earnshaw, editors, pp. 167-182, Springer 2002.
Also as Proceeding of Computer Graphics International 2002.
|
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2. Hao Zhang and
Eugene Fiume,
"Shape Matching of 3-D Contours using Normalized Fourier
Descriptors,"
in Proceeding of International Conference on Shape Modeling and
Applications (SMI),
IEEE Computer Society, pp. 261-268, 2002.
[PDF |
bibtex]
|
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1. John A. Brzozowski
and Hao Zhang,
"Delay-Insensitivity and Semi-Modularity,"
Formal Methods in System Design,
Kluwer Academic Publishers, March 2000, vol. 16,
pp. 191-218, 2000.
|
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8. Ramsay Dyer,
Hao Zhang, and
Torsten Moeller,
"A survey of Delaunay structures for surface representation,"
Technical Report TR-2009-1, School of Computing Science,
Simon Fraser University, 2009.
[PDF]
|
|
7. Ramsay Dyer,
Hao Zhang, and
Torsten Moeller,
"Observations on Gabriel meshes and Delaunay edge flips,"
Technical Report TR-2008-22, School of Computing Science,
Simon Fraser University, 2008.
[PDF]
|
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6. Jeff J. Yu and Hao Zhang, "A Prototype Sketch-Based Architectural Design System with Behavior Mode," Technical Report TR-2007-?, School of Computing Science, Simon Fraser University, November 2007. [PDF | AVI Video 1 | AVI Video 2]
|
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5. Ramsay Dyer,
Hao Zhang,
Torsten Moeller, and
Andrew Clements,
"An investigation of the spectral robustness of mesh Laplacians,"
Technical Report TR-2007-17, School of Computing Science,
Simon Fraser University, 2007.
[PDF]
|
|
4. Ramsay Dyer,
Hao Zhang, and
Torsten Moeller,
"On Voronoi-Delaunay Duality and Delaunay Meshes,"
Technical Report TR-2007-4, School of Computing Science,
Simon Fraser University, 2007.
[PDF]
|
|
3. John Y. S. Li and Hao Zhang,
Guaranteed Nonobtuse Meshes via Constrained
Optimization,
Technical Report TR-2006-13, School of Computing Science,
Simon Fraser University, May 2006.
[PDF]
|
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2. Rong Liu, Hao Zhang and
Oliver van Kaick,
An Investigation into Spectral Sequencing based on Graph
Distance,
Technical Report TR-2006-08, School of Computing Science,
Simon Fraser University, May 2006.
[PDF]
|
|
1. Hao Zhang and John A.
Brzozowski,
Delay-Insensitivity and the JTU-Rules,
Technical Report CS-97-11, Department of Computer Science,
University of Waterloo, November 1997.
|
Selected invited talks, tutorials, and courses
|
8. Bruno Levy and Hao Zhang,
Spectral Mesh Processing, SIGGRAPH Asia Courses (#32), 2009.
[wiki]
|
|
7. Hao Zhang,
Delaunay Meshes, invited
talk at Dynamic Graphics Project (DGP),
University of Toronto, Toronto, Ontario, Canada,
June 8, 2009.
[slides]
|
|
6. Ramsay Dyer and Hao
Zhang,
Delaunay Meshes,
Talk at Workshop on Computational Mathematics
on Discrete Surfaces, Banff, Alberta, Canada, Feb. 19, 2009.
[Part 1 |
Part 2]
|
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5. Hao Zhang,
Geometry processing in alternative domains,
invited talk at Zhejiang University, Hangzhou, China,
December 10, 2008.
[Slides]
|
|
4. Hao Zhang,
3D shape correspondence under bending and stretching
invited talk at the "City" Workshop,
Shenzhen Institue of Advanced Technologies, Shenzhen, China,
Dec. 6, 2008.
[Slides]
|
|
3. Hao Zhang,
Use of transforms in geometry processing, invited
talk at University of Calgary, Calgary, Alberta, Canada,
August 1, 2008.
|
|
2. Hao Zhang,
Eigenstructures for geometry analysis,
minisymposium talk at Shape Modeling International (SMI 2008),
Stony Brook, NY, USA, June, 2008.
|
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1. Hao Zhang,
Spectral processing for surface meshes,
minisymposium talk at SIAM Conf. on Geometric Design and
Computing (GDC),
talk at San Antonio, TX, USA,
November, 2007.
|