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Higher-Order Clique Reduction in Binary Graph Cut. Hiroshi Ishikawa. Nagoya City University Department of Information and Biological Sciences. Contribution of this work. Reduce any higher-order binary MRF into first order Adds variables
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Higher-Order Clique Reduction in Binary Graph Cut Hiroshi Ishikawa Nagoya City University Department of Information and Biological Sciences CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Contribution of this work Reduce any higher-order binary MRF into first order Adds variables Can also be used for multi-label energy, with the Fusion Move technique CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
FindX Given Y Close toY Smooth All pixels Neighboring pixels AssignsXv (= 0 or 1) to each pixel v Energy Minimization CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Better (Lower Energy) Worse (Higher Energy) A B C D Energy Minimization Good (Low Energy) Bad (High Energy) CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Energy Minimization Good (Low Energy) Bad (High Energy) 12 Bad 12 Bad 40 Good 40 Good CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Better (Lower Energy) Worse (Higher Energy) Energy Minimization A B C D 10 As 10 As 4 Bs 8 Bs 7 Cs 3 Cs 0 Ds 0 Ds CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Clique Clique Higher-Order Energy Third Order (Clique up to 4 pixels) First Order (Clique up to 2 pixels) Third Order (Clique up to 4 pixels) Clique Clique General Order C: a set of cliques CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
First-Order MRF Minimization Graph cuts Greig et al. ’89 Boykov et al. CVPR’98, PAMI2001(-exp.) Kolmogorov & Zabih. PAMI2004 Belief propagation Felzenszwalb & Huttenlocher. IJCV2006 Meltzer et al. ICCV2005 Tree-reweighted message passing Kolmogorov. PAMI2006 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Higher-Order MRF Minimization Graph cuts Kolmogorov & Zabih. PAMI2004 Freedman & Drineas. CVPR2005 Woodford et al. CVPR2008 Kohli et al. PAMI’08, Cremers&Grady ECCV’06 Rother et al. CVPR2009 Komodakis & Paragios. CVPR2009 Belief propagation Lan et al. ECCV2006 Potetz. CVPR2008 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Higher-Order MRF Minimization Graph cuts Kolmogorov & Zabih. PAMI2004 Freedman & Drineas. CVPR2005 Woodford et al. CVPR2008 Kohli et al. PAMI’08, Cremers&Grady ECCV’06 Rother et al. CVPR2009 Komodakis & Paragios. CVPR2009 Belief propagation Lan et al. ECCV2006 Potetz. CVPR2008 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Functions of Binary Variables Pseudo-Boolean function (PBF) Function of binary (0 or 1) variables Can always write uniquely as a polynomial One variable x : E0 (1x) + E1 x Two variables x, y : E00(1x) (1y) + E01(1x) y + E10x (1y) + E11x y Three variables x, y, z : E000(1x) (1y) (1z) + E001(1x) (1y) z +…+ E111x y z nth order binary MRF = (n+1)th degree PBF CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
2nd-Order (Cubic) Case Kolmogorov & Zabih. PAMI2004 Freedman & Drineas. CVPR2005 Reduce cubic PBF into quadratic one using B={0,1} xy z 0 0 0 0 0 1 0 1 1 1 1 1 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
2nd-Order (Cubic) Case If a < 0 Thus So, in a minimization problem, we can substitute by CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Higher-Order Case ifa < 0 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Higher-Order Case For a > 0 and d > 3, nothing similar is known → our contribution Imagine such a formula: CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Higher-Order Case For a > 0 and d > 3, nothing similar is known → our contribution Imagine such a formula: Notice LHS is symmetric i.e., if we swap the value of two variables, LHS is unchanged So RHS must be symmetric, too. CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Symmetric Polynomial Fact Any symmetric polynomial can be written as a polynomial in terms of elementary symmetric polynomials. If f(x, y,z,t) is quadratic symmetric, it can be written with a polynomial P(u,v) : CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Quartic (Degree 4) Case CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Quartic (Degree 4) Case CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Quartic (Degree 4) Case An exhaustive search fora, b, c, d, e yields CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Quintic (Degree 5) Case Similarly, and so on, until one can guess… CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
General Case where CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
General Case For each monomial, the number of new variable is: For instance, general quintic looks like: So the number is exponential in degree CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Multiple labels: Fusion Move Assume labels Labeling Y assigns a label Yv to each v Fusion Move Iteratively update Y : 1. Generate a proposed labeling P Lempitsky et al. ICCV2007 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Multiple labels: Fusion Move Assume labels Labeling Y assigns a label Yv to each v Fusion Move Iteratively update Y : 1. Generate a proposed labeling P 2. MergeY and P The merge defines a binary problem: “For each v, changeYv to Pvor not” Lempitsky et al. ICCV2007 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
0 1 0 0 1 0 1 0 0 1 0 1 1 1 0 0 Multiple labels: Fusion Move Fusion Move Iteratively update Y : 1. Generate a proposed labeling P 2. MergeY and P The merge defines a binary problem: “For each v, changeYv to Pvor not” Y P X CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
0 0 0 1 0 0 0 1 1 0 0 0 0 1 0 0 1 0 0 1 0 0 1 1 1 1 1 1 1 0 1 0 Multiple labels: Fusion Move Fusion Move Iteratively update Y : 1. Generate a proposed labeling P 2. MergeY and P The merge defines a binary problem: “For each v, changeYv to Pvor not” Y P X CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Fusion Move with QPBO QPBO (Roof duality) Minimizes submodular E globally. For non-submodular E, assigns each pixel 0, 1, or unlabeled With fusion move, by not changing unlabeled pixels to P, E doesn’t increase Hammer et al. 1984, Boros et al. 1991, 2006 Kolmogorov & Rother PAMI2007, Rother et al. CVPR2007 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Experiment: Denoising by FoE FoE (Fields of Experts) Roth & Black CVPR2005 A higher-order prior for natural images C: a set of cliques C : C : CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Experiment: Denoising by FoE Original Noise-added 3rd order 1st order CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Experiment: Denoising by FoE Energy (smaller the better) PSNR (larger the better) 32 45000 40000 31 35000 30 30000 29 25000 28 20000 27 15000 26 10000 25 5000 24 0 Lan et al. Potetz This work Lan et al. Potetz This work • Lan et al. ECCV2006 ~8 hours • Potetz. CVPR2008 ~30 mins • This work ~10 mins = 10 = 20 CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
12 0 10 0 8 0 6 0 4 0 2 0 0 5 0 10 0 15 0 20 0 25 0 Experiment: Denoising by FoE Energy & PSNR Two proposal generation strategies E (×1000) PSNR 2 7 blur & random 2 6 expansion 2 5 expansion 2 4 blur & random 2 3 2 2 0 5 0 10 0 15 0 20 0 25 0 time (sec.) time (sec.) CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Summary Reduce any higher-order binary MRF into first order Adds variables Number exponential in order For multi-label, can be used with Fusion Move with QPBO CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.
Thank you! Code available at http://www.nsc.nagoya-cu.ac.jp/~hi/ Acknowledgements Stefan Roth,Brian Potetz, and Vladimir Kolmogorov CVPR2009: IEEE Computer Society Conference on Computer Vision and Pattern Recognition Miami Beach, Florida. June 20-25.