1 Point registration via efficient convex relaxation Haggai

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1 Point registration via efficient convex relaxation Haggai Maron, Nadav Dym, Itay Kezurer, Shahar

1 Point registration via efficient convex relaxation Haggai Maron, Nadav Dym, Itay Kezurer, Shahar Kovalsky, Yaron Lipman Weizmann Institute of Science

2 Orthogonal Procrustes Problem Orthogonal

2 Orthogonal Procrustes Problem Orthogonal

3 Procrustes matching (PM) Permutation Orthogonal

3 Procrustes matching (PM) Permutation Orthogonal

4 Procrustes matching (PM) Orthogonal Given Orthogonal Point clouds Permutation

4 Procrustes matching (PM) Orthogonal Given Orthogonal Point clouds Permutation

5 Motivation embedding 3 D Non Rigid Alignment High dimensional Rigid Alignment [Jain et

5 Motivation embedding 3 D Non Rigid Alignment High dimensional Rigid Alignment [Jain et al. 2006, Ovsjanikov et al. 2008]

6 Previous work: Low dimensional PM • RANSAC [Fischler and Bolles 1981] Exponential in

6 Previous work: Low dimensional PM • RANSAC [Fischler and Bolles 1981] Exponential in the dimension • Combinatorial optimization [Gelfand et al. 2005, Yang et al. 2013] Worst case: exponential • ICP [Besl and Mckey 1992] Only local minimum guaranteed

7 Previous work: Shape matching • Functional maps [Ovsjanikov et al. 2012] Depends on

7 Previous work: Shape matching • Functional maps [Ovsjanikov et al. 2012] Depends on functional correspondences • SDP relaxations [Kezurer et al. 2015] Works for small-scale problems • LP relaxations [Chen and Koltun, 2015] Relies on extrinsic alignment

9 Convex Relaxation Orthogonal Permutation

9 Convex Relaxation Orthogonal Permutation

10 Convex Relaxation PM Convex Superset

10 Convex Relaxation PM Convex Superset

11 Convex Relaxation Slow & Tight LP SDP PM Fast & Loose

11 Convex Relaxation Slow & Tight LP SDP PM Fast & Loose

12 Why SDP relaxation? Theorem: If No noise, No symmetries Then SDP relaxation is

12 Why SDP relaxation? Theorem: If No noise, No symmetries Then SDP relaxation is exact! SDP

13 Why SDP relaxation? Theorem: No symmetries? If No noise, No symmetries Then SDP

13 Why SDP relaxation? Theorem: No symmetries? If No noise, No symmetries Then SDP relaxation is exact!

14 Why SDP relaxation? Theorem: If No noise, bilateral symmetries Then SDP relaxation is

14 Why SDP relaxation? Theorem: If No noise, bilateral symmetries Then SDP relaxation is exact!

15 Our Approach Use SDP relaxation for real problems Idea: exploit PM structure SDP

15 Our Approach Use SDP relaxation for real problems Idea: exploit PM structure SDP PM

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17 1 Huge! # points dimension

17 1 Huge! # points dimension

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21 1

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24 1 1

24 1 1

25 1 1

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26 1 1 1

26 1 1 1

27 Slow Fast Tight?

27 Slow Fast Tight?

28 Theorem: Equivalent Relaxations!

28 Theorem: Equivalent Relaxations!

29 Theorem: Equivalent Relaxations!

29 Theorem: Equivalent Relaxations!

30 Scalability of PM-SDP

30 Scalability of PM-SDP

31 Results: Isometric matching SCAPE dataset Source [Anguelov at al. 05] Target

31 Results: Isometric matching SCAPE dataset Source [Anguelov at al. 05] Target

32 Isometric matching SCAPE Raw Scans Source [Anguelov at al. 05] Target

32 Isometric matching SCAPE Raw Scans Source [Anguelov at al. 05] Target

33 Non-Isometric matching % Correspondences FAUST Source [Bogo et al. 14] Target Intra subject

33 Non-Isometric matching % Correspondences FAUST Source [Bogo et al. 14] Target Intra subject Inter subject

34 Non-Isometric matching [Giorgi et al. 07] SHREC 07’ Failure

34 Non-Isometric matching [Giorgi et al. 07] SHREC 07’ Failure

35 Limitations •

35 Limitations •

36 Summary •

36 Summary •

37 Acknowledgments: - European Research Council (ERC Starting Grant) - Israel Science Foundation Thank

37 Acknowledgments: - European Research Council (ERC Starting Grant) - Israel Science Foundation Thank you! • Code Available online! http: //www. wisdom. weizmann. ac. il/~haggaim/ • More results in the paper! Anatomical classification Collection alignment