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Unsupervised Shape Completion via Deep Prior in the Neural Tangent Kernel Perspective

Published:15 July 2021Publication History
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Abstract

We present a novel approach for completing and reconstructing 3D shapes from incomplete scanned data by using deep neural networks. Rather than being trained on supervised completion tasks and applied on a testing shape, the network is optimized from scratch on the single testing shape to fully adapt to the shape and complete the missing data using contextual guidance from the known regions. The ability to complete missing data by an untrained neural network is usually referred to as the deep prior. In this article, we interpret the deep prior from a neural tangent kernel (NTK) perspective and show that the completed shape patches by the trained CNN are naturally similar to existing patches, as they are proximate in the kernel feature space induced by NTK. The interpretation allows us to design more efficient network structures and learning mechanisms for the shape completion and reconstruction task. Being more aware of structural regularities than both traditional and other unsupervised learning-based reconstruction methods, our approach completes large missing regions with plausible shapes and complements supervised learning-based methods that use database priors by requiring no extra training dataset and showing flexible adaptation to a particular shape instance.

References

  1. Nachman Aronszajn. 1950. Theory of reproducing kernels. Trans. Amer. Math. Soc. 68, 3 (1950), 337–404. Google ScholarGoogle ScholarCross RefCross Ref
  2. Sanjeev Arora, Simon S. Du, Wei Hu, Zhiyuan Li, Russ R. Salakhutdinov, and Ruosong Wang. 2019. On exact computation with an infinitely wide neural net. In Proceedings of the International Conference on Advances in Neural Information Processing Systems. 8141–8150. Google ScholarGoogle ScholarDigital LibraryDigital Library
  3. Matan Atzmon and Yaron Lipman. 2020. SAL: Sign agnostic learning of shapes from raw data. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’20). 2565–2574.Google ScholarGoogle ScholarCross RefCross Ref
  4. Gerhard H. Bendels, Ruwen Schnabel, and Reinhard Klein. 2005. Detail-preserving surface inpainting. In Proceedings of the Symposium on Virtual Reality, Archaeology and Cultural Heritage (VAST’05), Mark Mudge, Nick Ryan, and Roberto Scopigno (Eds.). The Eurographics Association. Google ScholarGoogle ScholarDigital LibraryDigital Library
  5. Matthew Berger, Joshua A. Levine, Luis Gustavo Nonato, Gabriel Taubin, and Claudio T. Silva. 2013. A benchmark for surface reconstruction. ACM Trans. Graph. 32, 2 (Apr. 2013). Google ScholarGoogle ScholarDigital LibraryDigital Library
  6. Matthew Berger, Andrea Tagliasacchi, Lee M. Seversky, Pierre Alliez, Joshua A. Levine, Andrei Sharf, and Claudio Silva. 2014. State of the art in surface reconstruction from point clouds. In Proceedings of the Eurographics STAR (Proc. of EG’14), Sylvain Lefebvre and Michela Spagnuolo (Eds.). The Eurographics Association.Google ScholarGoogle Scholar
  7. Rohan Chabra, Jan Eric Lenssen, Eddy Ilg, Tanner Schmidt, Julian Straub, Steven Lovegrove, and Richard Newcombe. 2020. Deep local shapes: Learning local SDF priors for detailed 3D reconstruction. In Proceedings of the European Conference on Computer Vision (ECCV’20).Google ScholarGoogle Scholar
  8. Angel X. Chang, Thomas A. Funkhouser, Leonidas J. Guibas, Pat Hanrahan, Qi-Xing Huang, Zimo Li, Silvio Savarese, Manolis Savva, Shuran Song, Hao Su, Jianxiong Xiao, Li Yi, and Fisher Yu. 2015. ShapeNet: An information-rich 3D model repository. CoRR abs/1512.03012 (2015).Google ScholarGoogle Scholar
  9. Zezhou Cheng, Matheus Gadelha, Subhransu Maji, and Daniel Sheldon. 2019. A Bayesian perspective on the deep image prior. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’19).Google ScholarGoogle ScholarCross RefCross Ref
  10. Julian Chibane, Thiemo Alldieck, and Gerard Pons-Moll. 2020. Implicit functions in feature space for 3D shape reconstruction and completion. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’20).Google ScholarGoogle ScholarCross RefCross Ref
  11. Ulrich Clarenz, Udo Diewald, Gerhard Dziuk, Martin Rumpf, and Raluca E. Rusu. 2004. A finite element method for surface restoration with smooth boundary conditions. Comput.-aided Geom. Des. 21, 5 (2004), 427–445. Google ScholarGoogle ScholarDigital LibraryDigital Library
  12. Brian Curless and Marc Levoy. 1996. A volumetric method for building complex models from range images. In Proceedings of the 23rd Conference on Computer Graphics and Interactive Techniques (SIGGRAPH’96). Association for Computing Machinery, New York, NY, 303–312. Google ScholarGoogle ScholarDigital LibraryDigital Library
  13. Angela Dai, Christian Diller, and Matthias Nießner. 2020. SG-NN: Sparse generative neural networks for self-supervised scene completion of RGB-D scans. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’20).Google ScholarGoogle ScholarCross RefCross Ref
  14. Angela Dai, Charles Ruizhongtai Qi, and Matthias Nießner. 2017. Shape completion using 3D-encoder-predictor CNNs and shape synthesis. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’17).Google ScholarGoogle ScholarCross RefCross Ref
  15. James Davis, Stephen R. Marschner, Matt Garr, and Marc Levoy. 2002. Filling holes in complex surfaces using volumetric diffusion. In Proceedings of the 1st International Symposium on 3D Data Processing Visualization and Transmission. 428–441.Google ScholarGoogle ScholarCross RefCross Ref
  16. Simon S. Du, Kangcheng Hou, Russ R. Salakhutdinov, Barnabas Poczos, Ruosong Wang, and Keyulu Xu. 2019. Graph neural tangent kernel: Fusing graph neural networks with graph kernels. In Proceedings of the International Conference on Advances in Neural Information Processing Systems. 5723–5733. Google ScholarGoogle ScholarDigital LibraryDigital Library
  17. Haoqiang Fan, Hao Su, and Leonidas J. Guibas. 2017. A point set generation network for 3D object reconstruction from a single image. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’17).Google ScholarGoogle Scholar
  18. Michael Firman, Oisin Mac Aodha, Simon Julier, and Gabriel J. Brostow. 2016. Structured prediction of unobserved voxels from a single depth image. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’16).Google ScholarGoogle Scholar
  19. Free3D. 2020. Free3D. Retrieved from: https://free3d.com/.Google ScholarGoogle Scholar
  20. Matheus Gadelha, Rui Wang, and Subhransu Maji. 2019. Shape reconstruction using differentiable projections and deep priors. In Proceedings of the IEEE International Conference on Computer Vision (ICCV’19).Google ScholarGoogle ScholarCross RefCross Ref
  21. Yossi Gandelsman, Assaf Shocher, and Michal Irani. 2019. “Double-DIP”: Unsupervised image decomposition via coupled deep-image-priors. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’19).Google ScholarGoogle ScholarCross RefCross Ref
  22. Pallabi Ghosh, Vibhav Vineet, Larry S. Davis, Abhinav Shrivastava, Sudipta Sinha, and Neel Joshi. 2020. Deep Depth Prior for Multi-View Stereo. arxiv:cs.CV/2001.07791Google ScholarGoogle Scholar
  23. Rafael C. Gonzalez and Richard E. Woods. 2002. Digital Image Processing. Prentice Hall. 2002276271Google ScholarGoogle Scholar
  24. Benjamin Graham, Martin Engelcke, and Laurens van der Maaten. 2018. 3D semantic segmentation with submanifold sparse convolutional networks. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’18).Google ScholarGoogle Scholar
  25. Amos Gropp, Lior Yariv, Niv Haim, Matan Atzmon, and Yaron Lipman. 2020. Implicit geometric regularization for learning shapes. In Proceedings of the International Conference on Machine Learning (ICML’20).Google ScholarGoogle Scholar
  26. Xiaoguang Han, Zhen Li, Haibin Huang, Evangelos Kalogerakis, and Yizhou Yu. 2017. High-resolution shape completion using deep neural networks for global structure and local geometry inference. In Proceedings of the IEEE International Conference on Computer Vision (ICCV’17). Google ScholarGoogle ScholarCross RefCross Ref
  27. Boris Hanin and Mihai Nica. 2020. Finite depth and width corrections to the neural tangent kernel. In Proceedings of the International Conference on Learning Representations.Google ScholarGoogle Scholar
  28. Rana Hanocka, Amir Hertz, Noa Fish, Raja Giryes, Shachar Fleishman, and Daniel Cohen-Or. 2019. MeshCNN: A network with an edge. ACM Trans, Graph, (SIGGRAPH) 38, 4 (2019). Google ScholarGoogle ScholarDigital LibraryDigital Library
  29. Rana Hanocka, Gal Metzer, Raja Giryes, and Daniel Cohen-Or. 2020. Point2Mesh: A self-prior for deformable meshes. ACM Trans. Graph. (SIGGRAPH) 39, 4 (2020). Google ScholarGoogle ScholarDigital LibraryDigital Library
  30. Gur Harary, Ayellet Tal, and Eitan Grinspun. 2014. Context-based coherent surface completion. ACM Trans. Graph. 33, 1 (2014). Google ScholarGoogle ScholarDigital LibraryDigital Library
  31. Reinhard Heckel and Paul Hand. 2019. Deep decoder: Concise image representations from untrained non-convolutional networks. In Proceedings of the International Conference on Learning Representations.Google ScholarGoogle Scholar
  32. Pedro Hermosilla, Tobias Ritschel, and Timo Ropinski. 2019. Total denoising: Unsupervised learning of 3D point cloud cleaning. In Proceedings of the IEEE International Conference on Computer Vision (ICCV’19).Google ScholarGoogle Scholar
  33. Hui Huang, Shihao Wu, Daniel Cohen-Or, Minglun Gong, Hao Zhang, Guiqing Li, and Baoquan Chen. 2013. L1-medial skeleton of point cloud. ACM Trans. Graph. 32, 4 (2013). Google ScholarGoogle ScholarDigital LibraryDigital Library
  34. Zhiyang Huang, Nathan Carr, and Tao Ju. 2019. Variational implicit point set surfaces. ACM Trans. Graph. (SIGGRAPH) 38, 4 (2019). Google ScholarGoogle ScholarDigital LibraryDigital Library
  35. Arthur Jacot, Franck Gabriel, and Clement Hongler. 2018. Neural tangent kernel: Convergence and generalization in neural networks. In Proceedings of the International Conference on Advances in Neural Information Processing Systems. 8571–8580. Google ScholarGoogle ScholarDigital LibraryDigital Library
  36. Chiyu Max Jiang, Avneesh Sud, Ameesh Makadia, Jingwei Huang, Matthias Nießner, and Thomas Funkhouser. 2020. Local implicit grid representations for 3D scenes. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’20).Google ScholarGoogle ScholarCross RefCross Ref
  37. Tao Ju. 2009. Fixing geometric errors on polygonal models: A survey. J. Comput. Sci. Technol. 24, 1 (2009), 19–29. Google ScholarGoogle ScholarDigital LibraryDigital Library
  38. Michael Kazhdan, Matthew Bolitho, and Hugues Hoppe. 2006. Poisson surface reconstruction. In Proceedings of the 4th Eurographics Symposium on Geometry Processing. Google ScholarGoogle ScholarDigital LibraryDigital Library
  39. Michael Kazhdan and Hugues Hoppe. 2013. Screened Poisson surface reconstruction. ACM Trans. Graph. 32, 3 (2013). Google ScholarGoogle ScholarDigital LibraryDigital Library
  40. Diederik P. Kingma and Jimmy Ba. 2014. Adam: A method for stochastic optimization. arXiv preprint arXiv:1412.6980 (2014).Google ScholarGoogle Scholar
  41. Arno Knapitsch, Jaesik Park, Qian-Yi Zhou, and Vladlen Koltun. 2017. Tanks and temples: Benchmarking large-scale scene reconstruction. ACM Trans. Graph. 36, 4 (2017). Google ScholarGoogle ScholarDigital LibraryDigital Library
  42. Vladislav Kraevoy and Alla Sheffer. 2005. Template-based mesh completion. In Proceedings of the Eurographics Symposium on Geometry Processing, Mathieu Desbrun and Helmut Pottmann (Eds.). The Eurographics Association. Google ScholarGoogle ScholarDigital LibraryDigital Library
  43. Yann Lecun, Léon Bottou, Yoshua Bengio, and Patrick Haffner. 1998. Gradient-based learning applied to document recognition. Proc. IEEE 86, 11 (1998).Google ScholarGoogle ScholarCross RefCross Ref
  44. Jaehoon Lee, Lechao Xiao, Samuel Schoenholz, Yasaman Bahri, Roman Novak, Jascha Sohl-Dickstein, and Jeffrey Pennington. 2019. Wide neural networks of any depth evolve as linear models under gradient descent. In Proceedings of the International Conference on Advances in Neural Information Processing Systems. 8572–8583. Google ScholarGoogle ScholarDigital LibraryDigital Library
  45. Guo Li, Ligang Liu, Hanlin Zheng, and Niloy J. Mitra. 2010. Analysis, reconstruction and manipulation using arterial snakes. ACM Trans. Graph. 29, 6 (2010). Google ScholarGoogle ScholarDigital LibraryDigital Library
  46. Yangyan Li, Qian Zheng, Andrei Sharf, Daniel Cohen-Or, Baoquan Chen, and Niloy J. Mitra. 2011. 2D-3D fusion for layer decomposition of urban facades. In Proceedings of the IEEE International Conference on Computer Vision (ICCV’11). Google ScholarGoogle ScholarDigital LibraryDigital Library
  47. Peter Liepa. 2003. Filling holes in meshes. In Proceedings of the Eurographics/ACM SIGGRAPH Symposium on Geometry Processing (SGP’03). Eurographics Association, Goslar, DEU, 200–205. Google ScholarGoogle ScholarDigital LibraryDigital Library
  48. William E. Lorensen and Harvey E. Cline. 1987. Marching cubes: A high resolution 3D surface construction algorithm. ACM Siggraph Comput. Graph. 21, 4 (1987), 163–169. Google ScholarGoogle ScholarDigital LibraryDigital Library
  49. Niloy J. Mitra, Mark Pauly, Michael Wand, and Duygu Ceylan. 2013. Symmetry in 3D geometry: Extraction and applications. Comput. Graph. Forum 32, 6 (2013). Google ScholarGoogle ScholarDigital LibraryDigital Library
  50. Fangzhou Mu, Yingyu Liang, and Yin Li. 2020. Gradients as features for deep representation learning. In Proceedings of the International Conference on Learning Representations.Google ScholarGoogle Scholar
  51. Roman Novak, Lechao Xiao, Jiri Hron, Jaehoon Lee, Alexander A. Alemi, Jascha Sohl-Dickstein, and Samuel S. Schoenholz. 2020. Neural tangents: Fast and easy infinite neural networks in Python. In Proceedings of the International Conference on Learning Representations.Google ScholarGoogle Scholar
  52. Jeong Joon Park, Peter Florence, Julian Straub, Richard Newcombe, and Steven Lovegrove. 2019. DeepSDF: Learning continuous signed distance functions for shape representation. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’19).Google ScholarGoogle ScholarCross RefCross Ref
  53. Mark Pauly, Niloy J. Mitra, Joachim Giesen, Markus H. Gross, and Leonidas J. Guibas. 2005. Example-based 3D scan completion. In Proceedings of the Symposium on Geometry Processing. 23–32. Google ScholarGoogle ScholarDigital LibraryDigital Library
  54. Mark Pauly, Niloy J. Mitra, Johannes Wallner, Helmut Pottmann, and Leonidas J. Guibas. 2008. Discovering structural regularity in 3D geometry. ACM Trans. Graph. (SIGGRAPH) 27, 3 (2008). Google ScholarGoogle ScholarDigital LibraryDigital Library
  55. Songyou Peng, Michael Niemeyer, Lars Mescheder, Marc Pollefeys, and Andreas Geiger. 2020. Convolutional occupancy networks. In Proceedings of the European Conference on Computer Vision (ECCV’20).Google ScholarGoogle Scholar
  56. Danilo Jimenez Rezende, S. M. Ali Eslami, Shakir Mohamed, Peter Battaglia, Max Jaderberg, and Nicolas Heess. 2016. Unsupervised learning of 3D structure from images. In Proceedings of the International Conference on Advances in Neural Information Processing Systems. 4996–5004. Google ScholarGoogle ScholarDigital LibraryDigital Library
  57. Gernot Riegler, Ali Osman Ulusoy, Horst Bischof, and Andreas Geiger. 2017. Octnetfusion: Learning depth fusion from data. In Proceedings of the International Conference on 3D Vision (3DV’17). IEEE, 57–66.Google ScholarGoogle ScholarCross RefCross Ref
  58. Jason Rock, Tanmay Gupta, Justin Thorsen, JunYoung Gwak, Daeyun Shin, and Derek Hoiem. 2015. Completing 3D object shape from one depth image. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’15).Google ScholarGoogle ScholarCross RefCross Ref
  59. Ruwen Schnabel, Patrick Degener, and Reinhard Klein. 2009. Completion and reconstruction with primitive shapes. In Computer Graphics Forum, Vol. 28. Wiley Online Library, 503–512.Google ScholarGoogle Scholar
  60. Bernhard Schölkopf, Ralf Herbrich, and Alex J. Smola. 2001. A generalized representer theorem. In Proceedings of the International Conference on Computational Learning Theory. Springer, 416–426. Google ScholarGoogle ScholarDigital LibraryDigital Library
  61. Bernhard Schölkopf, Alexander J. Smola, and Klaus-Robert Müller. 1999. Kernel principal component analysis. In Advances in Kernel Methods: Support Vector Learning. The MIT Press, Cambridge, MA, 327–352. Google ScholarGoogle ScholarDigital LibraryDigital Library
  62. Andrei Sharf, Marc Alexa, and Daniel Cohen-Or. 2004. Context-based surface completion. ACM Trans. Graph. 23, 3 (2004). Google ScholarGoogle ScholarDigital LibraryDigital Library
  63. Abhishek Sharma, Oliver Grau, and Mario Fritz. 2016. VConv-DAE: Deep volumetric shape learning without object labels. In Proceedings of the European Conference on Computer Vision. Springer, 236–250.Google ScholarGoogle ScholarCross RefCross Ref
  64. John Shawe-Taylor and Nello Cristianini. 2004. Kernel Methods for Pattern Analysis. Cambridge University Press. Google ScholarGoogle ScholarDigital LibraryDigital Library
  65. Chao-Hui Shen, Hongbo Fu, Kang Chen, and Shi-Min Hu. 2012. Structure recovery by part assembly. ACM Trans. Graph. (SIGGRAPH Asia) 31, 6 (2012). Google ScholarGoogle ScholarDigital LibraryDigital Library
  66. Ivan Sipiran, Robert Gregor, and Tobias Schreck. 2014. Approximate symmetry detection in partial 3D meshes. In Computer Graphics Forum, Vol. 33. Wiley Online Library, 131–140. Google ScholarGoogle ScholarDigital LibraryDigital Library
  67. Vincent Sitzmann, Julien Martel, Alexander Bergman, David Lindell, and Gordon Wetzstein. 2020. Implicit neural representations with periodic activation functions. In Proceedings of the International Conference on Advances in Neural Information Processing Systems.Google ScholarGoogle Scholar
  68. Edward Smith and David Meger. 2017. Improved adversarial systems for 3D object generation and reconstruction. arXiv preprint arXiv:1707.09557 (2017).Google ScholarGoogle Scholar
  69. Pablo Speciale, Martin R. Oswald, Andrea Cohen, and Marc Pollefeys. 2016. A symmetry prior for convex variational 3D reconstruction. In Proceedings of the European Conference on Computer Vision. Springer, 313–328.Google ScholarGoogle ScholarCross RefCross Ref
  70. David Stutz and Andreas Geiger. 2018. Learning 3D shape completion from laser scan data with weak supervision. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’18).Google ScholarGoogle ScholarCross RefCross Ref
  71. Minhyuk Sung, Vladimir G. Kim, Roland Angst, and Leonidas Guibas. 2015. Data-driven structural priors for shape completion. ACM Trans. Graph. (SIGGRAPH Asia) 34, 6 (2015). Google ScholarGoogle ScholarDigital LibraryDigital Library
  72. Julián Tachella, Junqi Tang, and Mike Davies. 2020. CNN denoisers as non-local filters: The neural tangent denoiser. arXiv preprint arXiv:2006.02379 (2020).Google ScholarGoogle Scholar
  73. Matthew Tancik, Pratul Srinivasan, Ben Mildenhall, Sara Fridovich-Keil, Nithin Raghavan, Utkarsh Singhal, Ravi Ramamoorthi, Jonathan Barron, and Ren Ng. 2020. Fourier features let networks learn high frequency functions in low dimensional domains. In Proceedings of the International Conference on Advances in Neural Information Processing Systems.Google ScholarGoogle Scholar
  74. Maxim Tatarchenko, Stephan R. Richter, René Ranftl, Zhuwen Li, Vladlen Koltun, and Thomas Brox. 2019. What do single-view 3D reconstruction networks learn? In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’19).Google ScholarGoogle ScholarCross RefCross Ref
  75. Sebastian Thrun and Ben Wegbreit. 2005. Shape from symmetry. In Proceedings of the IEEE International Conference on Computer Vision (ICCV’05). Google ScholarGoogle ScholarDigital LibraryDigital Library
  76. Dmitry Ulyanov, Andrea Vedaldi, and Victor Lempitsky. 2018. Deep image prior. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’18). Google ScholarGoogle Scholar
  77. Max Welling and Yee Whye Teh. 2011. Bayesian learning via stochastic gradient Langevin dynamics. In Proceedings of the International Conference on Machine Learning (ICML’11). Google ScholarGoogle ScholarDigital LibraryDigital Library
  78. Francis Williams, Teseo Schneider, Claudio Silva, Denis Zorin, Joan Bruna, and Daniele Panozzo. 2019. Deep geometric prior for surface reconstruction. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR’19).Google ScholarGoogle ScholarCross RefCross Ref
  79. Zhirong Wu, Shuran Song, Aditya Khosla, Fisher Yu, Linguang Zhang, Xiaoou Tang, and Jianxiong Xiao. 2015. 3D ShapeNets: A deep representation for volumetric shapes. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition.Google ScholarGoogle Scholar
  80. Guoliang Xu. 2009. Mixed finite element methods for geometric modeling using general fourth order geometric flows. Comput.-aided Geom. Des. 26, 4 (May 2009). Google ScholarGoogle ScholarDigital LibraryDigital Library
  81. Wei Zhao, Shuming Gao, and Hongwei Lin. 2007. A robust hole-filling algorithm for triangular mesh. Vis. Comput. 23, 12 (2007), 987–997. Google ScholarGoogle ScholarDigital LibraryDigital Library
  82. Qingnan Zhou and Alec Jacobson. 2016. Thingi10K: A dataset of 10,000 3D-printing models. arXiv:1605.04797 (2016).Google ScholarGoogle Scholar
  83. Qian-Yi Zhou, Jaesik Park, and Vladlen Koltun. 2018. Open3D: A modern library for 3D data processing. arXiv:1801.09847 (2018).Google ScholarGoogle Scholar

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        cover image ACM Transactions on Graphics
        ACM Transactions on Graphics  Volume 40, Issue 3
        June 2021
        264 pages
        ISSN:0730-0301
        EISSN:1557-7368
        DOI:10.1145/3463476
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        Publication History

        • Published: 15 July 2021
        • Revised: 1 March 2021
        • Accepted: 1 March 2021
        • Received: 1 July 2020
        Published in tog Volume 40, Issue 3

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