Interactive Tracking of 2D Generic Objects with Spacetime Optimization

We present a continuous optimization framework for interactive tracking of 2D generic objects in a single video stream. The user begins with specifying the locations of a target object in a small set of keyframes; the system then automatically tracks locations of the objects by combining user constraints with visual measurements across the entire sequence. We formulate the problem in a spacetime optimization framework that optimizes over the whole sequence simultaneously. The resulting solution is consistent with visual measurements across the entire sequence while satisfying user constraints. We also introduce prior terms to reduce tracking ambiguity. We demonstrate the power of our algorithm on tracking objects with significant occlusions, scale and orientation changes, illumination changes, sudden movement of objects, and also simultaneous tracking of multiple objects. We compare the performance of our algorithm with alternative methods.