Part-Based Robust Tracking Using Online Latent Structured Learning

Despite many advances made in the area, deformable targets and partial occlusions continue to represent key problems in visual tracking. Structured learning has shown good results when applied to tracking whole targets, but applying this approach to a part-based target model is complicated by the need to model the relationships between parts and to avoid lengthy initialization processes. We thus propose a method that models the unknown parts by using latent variables. In doing so, we extend the online algorithm Pegasos to the structured prediction case (i.e., predicting the location of the bounding boxes) with latent part variables. We also incorporate the very recently proposed spatial constraints to preserve distances between parts. To better estimate the parts, and to avoid overfitting caused by the extra model complexity/capacity introduced by the parts, we propose a two-stage training process based on the primal rather than the dual form. We then show that the method outperforms the state of the arts in extensive experiments.