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This paper presents a method for 3D mesh analysis using randomized cuts, focusing on segmentation, visualization, registration, and deformation of meshes. The approach involves creating random segmentations, evaluating cut consistency, and exploring various applications. Results show improved articulation, noise reduction, and tessellation. The method proves to be efficient, with quick processing times and potential for optimizations. Future work includes exploring other randomization methods and applications like saliency analysis and feature detection. Acknowledgements to contributors and funding sources are also highlighted.
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Randomized Cuts for 3D Mesh Analysis Aleksey Golovinskiy and Thomas Funkhouser
Motivation Input Mesh Segmentation [http://www.aimatshape.net/research]
Key Idea Partition Function
Applications Segmentation Visualization Registration Deformation
Outline • Related Work • Method • Results • Applications
Related Work – Shape Analysis • Local Shape Properties • Curvature • Global Shape Properties • Shape Diameter Function [Rusinkiewicz 2004] [Shapira et al. 2008]
[Katz and Tal 2003] [Shlafman et al. 2002] [Shapira et al. 2008] Related Work – Mesh Segmentation • Shape Diameter Function • Fuzzy clustering and min cuts • K-means
Related Work – Mesh Segmentation • Partition function needs a segmentation method • Segmentation methods benefit from partition function: • Which is easier to segment? Dihedral Angles Partition Function
Related Work – Typical Cuts • [Gdalyahu et al. 2001]: image segmentation • Create many segmentations • Estimate likelihood of nodes in same segment • Extract connected components
Outline • Related Work • Method • Results • Applications
Method – Overview • Create randomized segmentations • Output: • Partition function • Cut consistency .5 .3 .01 …
[Shapira et al. 2008] α= .1 β= 500 γ= 20 α= .05 β= 700 γ= 18 α= .07 β= 650 γ= 11 α= .12 β= 400 γ= 26 Method – Randomization • Vary algorithms • Vary parameters • Jitter mesh • Algorithm-specific choices [Katz and Tal 2003]
Method – K-Means • Initialize K segment seeds, iterate: • Assign faces to closest seed • Move seed to cluster center • Randomization: random initial seeds
Method – Hierarchical Clustering • Initialize with a segment per face • Iteratively merge segments • Randomization: choose merge randomly
Method – Min Cut • Initialize with source + sink seed • Find min-cut (weighted towards middle) • Randomization: random source + sink
Outline • Related Work • Method • Results • Applications
Results – Timing • 4K models: 4 min per model • Not a problem: • 4K models capture salient parts • Computed once in model lifetime • Method-specific optimizations possible • Future work: recursive
Outline • Related Work • Method • Results • Applications
Applications – Visualization Dihedral Angles Shaded Surface Partition Function
.5 .3 .01 … Applications – Segmentation • Compute cut consistency • Split among most consistent cut, recurse
X X PartitionFunctionSampling UniformSampling Applications – Surface Correspondence
Applications – Deformation Input Mesh Partition Function Uniform Deformation Partition Function Deformation
Conclusion Discrete Segmentation Partition Function Randomized Segmentations
Future work • Other randomization methods • Other applications: saliency analysis, feature-preserving smoothing, skeleton embedding, feature detection, …
Future work • Multi-dimensional partition function Scale
Acknowledgements • Suggestions, code, feedback: • Adam Finkelstein, Szymon Rusinkiewicz, Philip Shilane, Yaron Lipman, Olga Sorkine and others • Models: • Aim@Shape, Stanford, Cyberware, Lior Shapira, Marco Attene, Daniela Giorgi, Ayellet Tal and others • Grants: • NSF (CNFS-0406415, IIS-0612231, and CCF-0702672) and Google
Related Work – Shape Analysis • Local Shape Properties • Shape Diameter Function • Diffusion Distance [Rusinkiewicz 2004] [de Goes et al. 2008] [Shapira et al. 2008]
Related Work – Random Cuts • [Karger and Stein 1996] • Randomized algorithm for finding min cut of a graph …
Related Work – Random Cuts • Our method vs Typical Cuts: • 3D domain • Goal is partition function • Different segmentation algorithm
Method – Dual Graph • Graph Nodes represent faces • Graph Arcs between adjacent faces • Lower cut cost at concave edges Input Model Graph Weights
Method – Min Cuts • Initialize with source + sink seed • Find min-cut • Often trivial • Increase weight close to source + sink • Discourage cuts at relative distance < s • Randomization: random source + sink • Scale: s
Results – Tessellation Reorder images
Applications – Deformation Uniform Partition Function
Method – Scale Multi-scale features?