Robust, Real-Time 3D Tracking of Multiple Objects with Similar Appearances

This paper proposes a novel method for tracking multiple moving objects and recovering their three-dimensional (3D) models separately using multiple calibrated cameras. For robustly tracking objects with similar appearances, the proposed method uses geometric information regarding 3D scene structure rather than appearance. A major limitation of previous techniques is foreground confusion, in which the shapes of objects and/or ghosting artifacts are ignored and are hence not appropriately specified in foreground regions. To overcome this limitation, our method classifies foreground voxels into targets (objects and artifacts) in each frame using a novel, probabilistic two-stage framework. This is accomplished by step-wise application of a track graph describing how targets interact and the maximum a posteriori expectation-maximization algorithm for the estimation of target parameters. We introduce mixture models with semiparametric component distributions regarding 3D target shapes. In order to not confuse artifacts with objects of interest, we automatically detect and track artifacts based on a closed-world assumption. Experimental results show that our method outperforms state-of-the-art trackers on seven public sequences while achieving real-time performance.