Local scene flow by tracking in intensity and depth

The scene flow describes the motion of each 3D point between two time steps. With the arrival of new depth sensors, as the Microsoft Kinect, it is now possible to compute scene flow with a single camera, with promising repercussion in a wide range of computer vision scenarios. We propose a novel method to compute a local scene flow by tracking in a Lucas-Kanade framework. Scene flow is estimated using a pair of aligned intensity and depth images but rather than computing a dense scene flow as in most previous methods, we get a set of 3D motion vectors by tracking surface patches. Assuming a 3D local rigidity of the scene, we propose a rigid translation flow model that allows solving directly for the scene flow by constraining the 3D motion field both in intensity and depth data. In our experimentation we achieve very encouraging results. Since this approach solves simultaneously for the 2D tracking and for the scene flow, it can be used for motion analysis in existing 2D tracking based methods or to define scene flow descriptors.