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Understanding shapes Fun with shapes. Li Guo 2011.07.04. Exploration of Continuous Variability in Collections of 3D Shapes (Sig11) Characterizing Structural Relationships in Scenes Using Graph Kernels (Sig11) Context-Based Search for 3D Models (SigA10)
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Understanding shapesFun with shapes Li Guo 2011.07.04
Exploration of Continuous Variability in Collections of 3D Shapes (Sig11) • Characterizing Structural Relationships in Scenes Using Graph Kernels (Sig11) • Context-Based Search for 3D Models (SigA10) • Shape google: Geometric words and expressions for invariant shape retrieval (TOG11) • Making Burr Puzzles from 3D Models (Sig11) • A Geometric Study of V-style Pop-ups: Theories and Algorithms (Sig11) • Depixelizing Pixel Art (Sig11) • Digital Micrography (Sig11)
Exploration of Continuous Variability in Collections of 3D Shapes
What(Video) • Propose a new technique for exploring unorganized collections of 3D models
Motivation • 3D models become more and more • Text-based search • Many within class • Navigating directly in descriptor space • High-dimensional • Not intuitive • Example-based retrieval
Related work • Morphable models and deformation modeling • Global correspondence detection remains a challenging open problem • Exploring shape datasets • Text keywords • Proxies • Example-based search
Selling points • We present a template-based interface for exploring collections of similar 3D models via constrained direct manipulation. • We introduce a novel technique to convert descriptor variability into a deformation model for a template shape without relying on correspondences between shapes.
Descriptor variability and template deformations Shape descriptor Shape PCA basis Deformation Space Template deformation PCA basis
Template selection and deformation space • Template selection • Order the shapes by the distance to the average descriptor • Filter the shapes have many components • Deformation space • Template shape with C components • 6C deformation parameters(3 translation and 3 scaling)
Future work • An explicit encoding of the part connectivity • A convex formulation of a similar optimization problem • Outlier detection for shape retrieval • Analyzing the relation of discrete variability in the shape • Extensions to our exploration interface
Characterizing Structural Relationships in Scenes Using Graph Kernels
Authors ?
What • Represent scenes as graphs that encode models and their semantic relationships • Applications • Finding similar scenes • Relevance feedback • Context-based model search
Motivation • Scene comparison
Related work • 3D Model Search • Scene Comparison • [Harchaoui and Bach 2007] Image comparison
Representing Scenes As Graphs • Enclosure, Horizontal Support, Vertical Contact, Oblique Contact
Graph Comparison • Node Kernel • Edge Kernel • Graph Kernel: [Harchaoui and Bach 2007] • Embedding the graphs in a very high dimensional feature space and computing an inner product
Dataset • Google 3D Warehouse • Most have scene graph • Standardize the tagging and segmentation (mimics the method such as PASCAL,MSRC, and LabelMe [Russell et al. 2008]
Limitations • Simple relationship • Many scenes were not reasonably segmented
Future work • Software that is aware of the relationships expressed in 3D scenes has significant potential to augment the scene design process.
What • Context search
Motivation • 3D model search • Scene modeling • The goal of this research is to develop a context-based 3D search engine
Related work • Geometric Search Engines • Spatial Context in Computer Vision • The context challenge
Dataset • Google 3D Warehouse • Most have scene graph • Standardize the tagging and segmentation (mimics the method such as PASCAL,MSRC, and LabelMe [Russell et al. 2008]
Overview • Observations • All pairs of object co-occurrence across all scenes • Spatial Relationships • Object Similarity • Model Ranking
Failure Cases • Geometrically very similar to a relevant object but semantically very different • Spatial relationships are overly simplistic
Future work • Extracting more meaningful spatial relationships between objects • Intelligently perform complex actions(意识流)
Shape Google: geometric words and expressions for invariant shape retrieval
Authors LEONIDAS J. GUIBAS MAKS OVSJANIKOV Alex M. Bronstein Michael M. Bronstein
What • Non-rigid shape search and retrieval