Grouping of Articulated Objects with Common Axis

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. We consider two moving objects and assume that the rigid SfM problem has been solved for each of them separately. We propose a method which helps to decide whether an object is rotating around an axis defined by another moving object. The theories of the proposed method is discussed in detail. Experimental results for synthetic and real data are presented.