Title
Closed-Form Solutions for Low-Rank Non-Rigid Reconstruction
Abstract
Recovering the motion of a non-rigid body from a set of monocular images permits the analysis of dynamic scenes in uncontrolled environments. However, the extension of factorisation algorithms for rigid structure from motion to the low-rank non- rigid case has proved challenging. This stems from the comparatively hard problem of finding a linear ``corrective transform'' which recovers the projection and structure matrices from an ambiguous factorisation. We elucidate that this greater difficulty is due to the need to find multiple solutions to a non-trivial problem, casting a number of previous approaches as alleviating this issue by either a) introducing constraints on the basis, making the problems non- identical, or b) incorporating heuristics to encourage a diverse set of solutions, making the problems inter-dependent. While it has previously been recognised that finding a single solution to this problem is sufficient to estimate cameras, we show that it is possible to bootstrap this partial solution to find the complete transform in closed-form. However, we acknowledge that our method minimises an algebraic error and is thus inherently sensitive to deviation from the low-rank model. We compare our closed-form solution for non-rigid structure with known cameras to the closed-form solution of Dai et al.~\cite{Dai2012}, which we find to produce only coplanar reconstructions. We therefore make the recommendation that 3D reconstruction error always be measured relative to a trivial reconstruction such as a planar one.
Year
DOI
Venue
2015
10.1109/DICTA.2015.7371247
2015 International Conference on Digital Image Computing: Techniques and Applications (DICTA)
Keywords
Field
DocType
low-rank nonrigid reconstruction,nonrigid body motion recovery,monocular images,linear corrective transform,projection matrices,structure matrices,coplanar reconstructions,3D reconstruction error
Structure from motion,Iterative reconstruction,Computer vision,Algebraic number,Matrix (mathematics),Computer science,Heuristics,Artificial intelligence,Factorization,Bootstrapping (electronics),3D reconstruction
Conference
Citations 
PageRank 
References 
2
0.36
0
Authors
5
Name
Order
Citations
PageRank
Jack Valmadre146614.08
Sridha Sridharan22092222.69
Simon Denman350956.72
Clinton Fookes474397.41
Simon Lucey52034116.77