Real-time software synchronisation of webcams for live 3D tracking

This paper adresses the multiple-webcam synchronisation problem for dynamic scenes by proposing a new triangulation method which is invariant to the temporal offset of the webcams. Our method estimates the correct positions of the tracked points without knowing or directly estimating the temporal offset between the cameras. Instead, it relies on the epipolar geometry of the cameras. In the presence of a temporal delay, a tracked point does not lay on its corresponding epipolar line, thereby inducing triangulation errors. By intersecting its motion trajectory with the corresponding epipolar line, an accurate triangulation can be obtained. One major advantage of our approach is that the temporal offset can change throughout the sequence. Temporal offset variations occur frequently when using webcams. The major contribution of this work is making a temporal offset invariant triangulation solution.