Estimating approximate average shape and motion of deforming objects with a monocular view

Abstract

With a monocular view, the nonrigid recovery of 3D motion and time-varying shapes of a deforming object may be impossible without any prior information, because ambiguous, multiple solutions exist for motion and shapes which produce the same projection image. In this paper, as a preceding step to the nonrigid recovery of a deforming object, we develop an approach for estimating the approximate average shape and motion of the object. This reasonably solves the ambiguity problem in nonrigid recovery. By investigating the internal structures of nonrigid objects, we introduce a novel concept, called DoN (Degree of Nonrigiclity). Based on this, we propose an iterative certainty reweighted factorization method. In addition, we refine and improve the method by reformulating it in a robust manner to cope with outliers existing in the tracked features. Finally, we present some experimental results on both synthetic data and a real video sequence.