An Algorithm for Optimal Transport between a Simplex Soup and a Point Cloud
Abstract
We propose a numerical method to find the optimal transport map between a measure supported on a lower-dimensional subset of $\mathbb{R}^d$ and a finitely supported measure. More precisely, the source measure is assumed to be supported on a simplex soup, i.e., on a union of simplices of arbitrary dimension between 2 and $d$. As in [F. Aurenhammer, F. Hoffman, and B. Aronov, Algorithmica, 20 (1998), pp. 61--76] we recast this optimal transport problem as the resolution of a nonlinear system where one wants to prescribe the quantity of mass in each cell of the so-called Laguerre diagram. We prove the convergence with linear speed of a damped Newton's algorithm to solve this nonlinear system. The convergence relies on two conditions: (i) a genericity condition on the point cloud with respect to the simplex soup, and (ii) a (strong) connectedness condition on the support of the source measure defined on the simplex soup. Finally, we apply our algorithm in ${R}^3$ to compute optimal transport plans between a measure supported on a triangulation and a discrete measure. We also detail some applications such as optimal quantization of a probability density over a surface, remeshing, or rigid point set registration on a mesh.
1. , Minkowski-type theorems and least-squares clustering , Algorithmica , 20 ( 1998 ), pp. 61 -- 76 .
2. , Numerical solution of the optimal transportation problem using the Monge--Ampere equation , J. Comput. Phys. , 260 ( 2014 ), pp. 107 -- 126 .
3. , The auction algorithm: A distributed relaxation method for the assignment problem , Ann. Oper. Res. , 14 ( 1988 ), pp. 105 -- 123 .
4. , Method for registration of $3$-D shapes, in Robotics-DL Tentative ,
International Society for Optics and Photonics , 1992 , pp. 586 -- 606 .5. , On the numerical solution of the problem of reflector design with given far-field scattering data , in Monge Ampère Equation: Applications to Geometry and Optimization: NSF-CBMS Conference on the Monge Ampère Equation, Applications to Geometry and Optimization , 1997 , Florida Atlantic University , Contemp . Math. 226, American Mathematical Society, 1999, pp. 13 -- 32 .
6. , From Knothe's transport to Brenier's map and a continuation method for optimal transport , SIAM J. Math. Anal. , 41 ( 2010 ), pp. 2554 -- 2576 , https://doi.org/10.1137/080740647.
7. , Far-field reflector problem and intersection of paraboloids , Numer. Math. , 2 ( 2016 ), pp. 389 -- 411 .
8. , Blue noise through optimal transport , ACM Trans. Graphics , 31 ( 2012 ), 171 .
9. , Feature-preserving surface reconstruction and simplification from defect-laden point sets , J. Math. Imaging Vision , 48 ( 2014 ), pp. 369 -- 382 .
10. , Application of the Wasserstein metric to seismic signals , Commun. Math. Sci. , 12 ( 2014 ), pp. 979 -- 988 .
11. , The geometry of optimal transportation , Acta Math. , 177 ( 1996 ), pp. 113 -- 161 .
12. , Convergence of a Newton Algorithm for Semi-discrete Optimal Transport, preprint, https://arxiv.org/abs/1603.05579 , 2016 . , https://arxiv.org/abs/1603.05579.
13. , A numerical algorithm for $L^2$ semi-discrete optimal transport in $3$D , ESAIM Math. Model. Numer. Anal. , 49 ( 2015 ), pp. 1693 -- 1715 .
14. , On the limited memory BFGS method for large scale optimization , Math. Programming , 45 ( 1989 ), pp. 503 -- 528 .
15. , On the regularity of solutions of optimal transportation problems , Acta Math. , 202 ( 2009 ), pp. 241 -- 283 .
16. . Wang, Regularity of potential functions of the optimal transportation problem , Arch. Ration. Mech. Anal. , 177 ( 2005 ), pp. 151 -- 183 .
17. , Variance-minimizing transport plans for inter-surface mapping , ACM Trans. Graphics , 36 ( 2017 ), 39 .
18. , A multiscale approach to optimal transport , Computer Graphics Forum , 30 ( 2011 ), pp. 1583 -- 1592 .
19. , Discretization of the 3D Monge-Ampère operator, between wide stencils and power diagrams , ESAIM Math. Model. Numer. Anal., 49 ( 2015 ), pp. 1511 -- 1523 .
20. , On the numerical solution of the equation $(\partial^2 z/\partial x^2) + (\partial^2z/\partial y^2) - (\partial^2z/\partial x\partial y)$ and its discretizations, I , Numer. Math. , 54 ( 1989 ), pp. 271 -- 293 .
21. , Optimal Transport for Applied Mathematicians , Birkhäuser , 2015 .
22. , A hierarchical approach to optimal transport , in
International Conference on Scale Space and Variational Methods in Computer Vision ,Springer , 2013 , pp. 452 -- 464 .23. , Convolutional Wasserstein distances: Efficient optimal transportation on geometric domains , ACM Trans. Graphics , 34 ( 2015 ), 66 .
24. , Area preserving brain mapping , in
Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition , 2013 , pp. 2235 -- 2242 .25. , CGAL User and Reference Manual , CGAL Editor ial Board , 4.9 ed., 2016 , http://doc.cgal.org/4.9/Manual/packages.html. , http://doc.cgal.org/4.9/Manual/packages.html.
26. , A transportation $L^p$ distance for signal analysis , J. Math. Imaging Vision , 59 ( 2017 ), pp. 187 -- 210 .
27. , Optimal Transport: Old and New , Springer-Verlag , 2009 .