Multi-view Synchronization of Human Actions and Dynamic Scenes

This paper deals with the temporal synchronization of image sequences. Two in- stances of this problem are considered: (a) synchronization of human actions and (b) synchronization of dynamic scenes with view changes. To address both tasks and to re- liably handle large view variations, we use self-similarity matrices which remain stable across views. We propose time-adaptive descriptors that capture the structure of these matrices while being invariant to the impact of time warps between views. Synchro- nizing two sequences is then performed by aligning their temporal descriptors using the Dynamic Time Warping algorithm. We present quantitative comparison results between time-fixed and time-adaptive descriptors for image sequences with different frame rates. We also illustrate the performance of the approach on several challenging videos with large view variations, drastic independent camera motions and within-class variability of human actions.