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SIGGRAPH Asia 2013 Yunhai Wang Shenzhen VisuCA Key Lab/SIAT Minglun Gong Tianhua Wang Daniel Cohen-Or Hao Zhang Baoquan Chen. Projective Analysis for 3D Shape Segmentation. Speaker : Sze. Outline. Introduction Related Work Overview
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SIGGRAPH Asia 2013 YunhaiWang Shenzhen VisuCA Key Lab/SIAT MinglunGong TianhuaWang Daniel Cohen-Or HaoZhang Baoquan Chen Projective Analysis for 3D Shape Segmentation Speaker : Sze
Outline • Introduction • Related Work • Overview • Back-projection and Label Transfer • Results • Discussion and Future Work
Outline • Introduction • Related Work • Overview • Back-projection and Label Transfer • Results • Discussion and Future Work
Introduction • We introduce projective analysis for semantic segmentation and labeling of 3D shapes.
Outline • Introduction • Related Work • Overview • Back-projection and Label Transfer • Results • Discussion and Future Work
Related Work • Shape Segmentation and labeling • Data-driven analysis • Projective shape analysis • Image and shape hybrid processing • Image retrieval • Image label transfer
Related Work • Shape Segmentation and labeling • [Shamir 2008] • Difficult to develop precise mathematical models for what a meaningful shape part is
Related Work • Data-driven analysis • [Kalogerakis et al. 2010; van Kaick et al. 2011] • [Golovinskiy and Funkhouser 2009; Xu et al. 2010; Sidiet al. 2011] • [Wang et al. 2012].
Related Work • Projective shape analysis • [Muraseand Nayar1995], [Lindstrom and Turk 2000] • Our work applies projective analysis to a new application: semantic segmentation of 3D shapes
Related Work • Image and shape hybrid processing • [Li et al. 2011], [Chang et al. 2009]
Related Work • Image retrieval • [Xiao et al. 2010], [Baddeley 1992] • We do not only retrieve a 2D shape but also infer a semantic labeling of its interior
Related Work • Image label transfer • [Shotton et al. 2006],[Liu et al. 2011a],[Zhang et al. 2010]
Outline • Introduction • Related Work • Overview • Back-projection and Label Transfer • Results • Discussion, limitations and Future Work
Overview • We assume that both the input and the objects captured in the labeled images are in their upright orientations
Overview • Dataset • Large collection of images gathered from the Web • Organized into several semantic classes • Semantic parts of the object are manually segmented and labeled • Foreground object • Using Grabcut[Rother et al. 2004] • Normalizeall labeled images to the same size through uniform scaling
Outline • Introduction • Related Work • Overview • Back-projection and Label Transfer • Results • Discussion, limitations and Future Work
Back-projection and Label Transfer • Retrieve labeled images using projections • Matching between 1D shapes • Matching between 2D shapes • Transfer label information to projections • Back-project labels and graph cuts optimization
Back-projection and Label Transfer • Retrieve labeled images using projections • Matching between 1D shapes • Matching between 2D shapes • Transfer label information to projections • Back-project labels and graph cuts optimization
Retrieve labeled images using projections • [Chen et al. 2003] • Turn off the lighting • Apply the orthogonal projection
Retrieve labeled images using projections • [Belongie et al. 2002;Ling and Jacobs 2007]
Retrieve labeled images using projections • For each projection T, we first compute its slab representation • Use it to evaluate its dissimilarities to each labeled image S
Back-projection and Label Transfer • Retrieve labeled images using projections • Matching between 1D shapes • Matching between 2D shapes • Transfer label information to projections • Back-project labels and graph cuts optimization
Matching between 1D shapes • Symmetric Hausdorff distance
Matching between 1D shapes • Symmetric Hausdorff distance 1 0
Matching between 1D shapes • Bi-class symmetric Hausdorffdistance • ,: all the white pixels in the line
Matching between 1D shapes • n : number of horizontal (vertical) slabs • : row (column) number of the representative scanline • T[] : returns the scanline • : height (width)
Back-projection and Label Transfer • Retrieve labeled images using projections • Matching between 1D shapes • Matching between 2D shapes • Transfer label information to projections • Back-project labels and graph cuts optimization
Matching between 2D shapes • Warp-aligned dissimilarity • T : unlabeled • S : labeled • S[] : scanlinesin S • w():axial-aligned mapping functionthatscales slabs in T to match those in S
Matching between 2D shapes • Slab matching cost matrix M
Matching between 2D shapes • Slab matching cost matrix M
Matching between 2D shapes • Dynamic Time Warping (DTW) • [Berndt and Clifford 1994]
Back-projection and Label Transfer • Retrieve labeled images using projections • Matching between 1D shapes • Matching between 2D shapes • Transfer label information to projections • Back-project labels and graph cuts optimization
Transfer label information to projections • Confidence map
Transfer label information to projections • Confidence map • A per-image term : / • A per-scanline term : • maps scanlines from T to S
Transfer label information to projections • Confidence map • A per-pixel term : • : column number of the pixel in Sthat is used to label (i, j) in T • : Gaussian support (set to 150 in our experiments)
Transfer label information to projections • Confidence map • A per-pixel term : T S
Back-projection and Label Transfer • Retrieve labeled images using projections • Matching between 1D shapes • Matching between 2D shapes • Transfer label information to projections • Back-project labels and graph cuts optimization
Back-project labels and graph cuts optimization • : primitive in the 3D shape • : label • : The set containing all pixels • () : Dirac’s delta function • : label in S image
Back-project labels and graph cuts optimization • Multi-label alpha expansion graph-cut algorithm [Boykov et al. 2001]
Back-project labels and graph cuts optimization • V : Given by the primitives of the shape • E : {,} • : If the primitives represented by nodes and vare connected • : k nearest neighbors in Kd-tree
Back-project labels and graph cuts optimization • : the labels assigned to nodes and v • : Weights
Back-project labels and graph cuts optimization • : Length of the edge
Back-project labels and graph cuts optimization • : the positive dihedral angle • : Euclidian distance between nodes and
Outline • Introduction • Related Work • Overview • Back-projection and Label Transfer • Results • Discussion and Future Work
Results • Experiment • Images resolution : 512 x512 • 30 seconds of matching a projection with 500 labeled images • Input meshes(20K triangles) • 1 minute of label transfer • 1 minute of back-projection