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Nuno M. Pinho da Silva
Email: nmps(at)isr(dot)ist(dot)utl(dot)pt
Phone: (+351) 218 418 284
Fax: (+351) 218 418 083
Contact: Instituto de Sistemas e Robótica
Torre Norte, Piso 7
Instituto Superior Técnico
Av. Rovisco Pais, 1
1049-001 Lisboa
Portugal
"The beliefs which we have most warrant for, have no safeguard to rest on, but a standing invitation to the whole world to prove them unfounded." - John Stuart Mill

My research aims at finding efficient algorithms for extracting semantic content from data. Currently my work lies at the intersection of Computer Vision, Machine Learning and Knowledge Discovery.

Selected Publications:
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  • da Silva, N. P. and Costeira, J. P.. " The Normalized Subspace Inclusion: Robust Clustering of Motion Subspaces", The Twelfth IEEE International Conference on Conputer Vision (ICCV), Kyoto, Japan, September, 2009.

    The Normalized Subspace Inclusion (NSI) is a criterion for linear subspace clustering. It remains geometrically consistent where most of the previous proposed criteria fail to do so, because it is invariant to both the orthogonal and inclusion relationship between subspaces. By clustering the GMC geometric solution (see the CVPR'08 paper), using the NSI similarity, we get a rigid motion interpretation for the linear subspaces underlying the different groups of image trajectories.
  • da Silva, N. P. and Costeira, J. P.. " Subspace segmentation with outliers: a Grassmannian approach to the maximum consensus subspace", IEEE Computer Society Conference on Conputer Vision and Pattern Recognition (CVPR), Anchorage, Alaska, USA, June, 2008.

    Here we present sufficient conditions defining the intrinsic maximum consensus statistic on Smooth Manifolds. In particular, we explore the riemannian structure of the Grassmann manifold, using a geometric optimization algorithm, to built the Grassmannian Maximum Consensus (GMC): a new maximum consensus based method for robust linear subspace segmentation, avoiding random search and voting procedures, rank estimation, and with quadratic convergence rate near the optima. Also, the subspace dimension arises as a byproduct of the segmentation method.
Education: 2010
  • Ph.D. Degree in Electrical and Computer Engineering at Instituto Superior Técnico, Portugal.

    The final dissertation Robust Nonmetric Perception of Moving Rigid Bodies (June, 2010) addresses the problem of perceiving rigid motion in dynamic scenes. It proves constructively the existence of the Smooth Maximum Consensus (SMC) map, thus providing a tool for intrinsic robust fitting on Riemannian Manifolds. It develops the Grassmannian Maximum Consensus (GMC) method for robust linear subspace segmentation, the Normalized Subspace Inclusion (NSI) criterion for subspace clustering and a new algorithm for Planar Factorization.
2005
  • Master Degree in Electrical and Computer Engineering at Instituto Superior Técnico, Portugal.

    The final dissertation Global Robust Image Registration (June, 2005) (June, 2005) addresses two concepts of robustness in global image registration: (i) robustness to outliers (proposed solution: the IGLOS methodology) and (ii) robustness to the uncertainty in the model of the image transformations (proposed solution: the L-infinity algorithm).
2002
Academic: 2010 -
2009
2005 - 2006
Last update: June 2010