Levente Hajder: 3D Motion Grouping of Articulated Objects

We address the problem of nonrigid Structure from Motion (SfM). Several methods have been published recently which try to solve the task of tracking, segmenting, or reconstructing nonrigid 3D objects in motion. Most of these papers focus on deformable objects. We deal with the segmentation of articulated objects, that is, nonrigid objects composed of several moving rigid objects. This study is the first part of a planned series of papers. We consider two moving objects and assume that the rigid SfM problem has been solved for each of them separately. Two novel methods are proposed: (i)~a method that determines whether the two objects are connected; (ii)~a method that determines if the first object is rotating around an axis defined by the second object. The theories and the algorithms of the proposed methods are discussed in detail. Experimental results for synthetic and real data are presented.