Abstract
We present a simple and fast geometric method for modeling data by a union of affine subspaces. The method begins by forming a collection of local best-fit affine subspaces, i.e., subspaces approximating the data in local neighborhoods. The correct sizes of the local neighborhoods are determined automatically by the Jones' β 2 numbers (we prove under certain geometric conditions that our method finds the optimal local neighborhoods). The collection of subspaces is further processed by a greedy selection procedure or a spectral method to generate the final model. We discuss applications to tracking-based motion segmentation and clustering of faces under different illuminating conditions. We give extensive experimental evidence demonstrating the state of the art accuracy and speed of the suggested algorithms on these problems and also on synthetic hybrid linear data as well as the MNIST handwritten digits data; and we demonstrate how to use our algorithms for fast determination of the number of affine subspaces.
Original language | English (US) |
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Pages (from-to) | 217-240 |
Number of pages | 24 |
Journal | International Journal of Computer Vision |
Volume | 100 |
Issue number | 3 |
DOIs | |
State | Published - Dec 2012 |
Bibliographical note
Funding Information:Acknowledgements This work was supported by NSF grants DMS-06-12608, DMS-08-11203, DMS-09-15064 and DMS-09-56072. Thanks to the action editor and the reviewers for the careful reading and comments; Peter Jones, Mauro Maggioni and Amit Singer for discussions that motivated our exploration for a multiscale SVD-based HLM algorithm; Ehsan Elhamifar and René Vidal for answering various questions regarding the SSC code and providing us an initial version before the code was available to the public; Allen Yang for clarifying the estimation of the number of clusters in GPCA; and the IMA for a stimulating multi-manifold modeling workshop.
Keywords
- Face clustering
- High-dimensional data
- Hybrid linear modeling
- Local PCA
- Motion segmentation
- Spectral clustering
- Subspace clustering