Camera Alignment using Trajectory Intersections in Unsynchronized Videos

This paper addresses the novel and challenging prob-lem of aligning camera views that are unsynchronized by low and/or variable frame rates using object trajec-tories. Unlike existing trajectory-based alignment meth-ods, our method does not require frame-to-frame synchro-nization. Instead, we propose using the intersections of corresponding object trajectories to match views. To find these intersections, we introduce a novel trajectory match-ing algorithm based on matching Spatio-Temporal Con-text Graphs (STCGs). These graphs represent the distances between trajectories in time and space within a view, and are matched to an STCG from another view to find the cor-responding trajectories. To the best of our knowledge, this is one of the first attempts to align views that are unsyn-chronized with variable frame rates. The results on simu-lated and real-world datasets show trajectory intersections are a viable feature for camera alignment, and that the tra-jectory matching method performs well in real-world sce-narios. 1