Separable Spatiotemporal Priors for Convex Reconstruction of Time-Varying 3D Point Clouds

  • Tomas Simon
  • Jack Valmadre
  • Iain Matthews
  • Yaser Sheikh
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8691)

Abstract

Reconstructing 3D motion data is highly under-constrained due to several common sources of data loss during measurement, such as projection, occlusion, or miscorrespondence. We present a statistical model of 3D motion data, based on the Kronecker structure of the spatiotemporal covariance of natural motion, as a prior on 3D motion. This prior is expressed as a matrix normal distribution, composed of separable and compact row and column covariances. We relate the marginals of the distribution to the shape, trajectory, and shape-trajectory models of prior art. When the marginal shape distribution is not available from training data, we show how placing a hierarchical prior over shapes results in a convex MAP solution in terms of the trace-norm. The matrix normal distribution, fit to a single sequence, outperforms state-of-the-art methods at reconstructing 3D motion data in the presence of significant data loss, while providing covariance estimates of the imputed points.

Keywords

Matrix normal trace-norm spatiotemporal missing data 

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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Tomas Simon
    • 1
  • Jack Valmadre
    • 2
    • 3
  • Iain Matthews
    • 4
    • 1
  • Yaser Sheikh
    • 1
  1. 1.Carnegie Mellon UniversityUSA
  2. 2.Queensland University of TechnologyAustralia
  3. 3.Commonwealth Scientific and Industrial Research OrganisationAustralia
  4. 4.Disney Research PittsburghUSA

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