3D Reconstruction from public webcams

In this paper, we investigate the possibility of reconstructing the 3D geometry of a scene captured by multiple webcams. The number of publicly accessible webcams is already large and it is growing every day. A logical question arises - can we use this free source of data for something beyond leisure activities? The challenge is that no internal, external, or temporal calibration of these cameras is available. We show that using recent advances in computer vision, we successfully calibrate the cameras, perform 3D reconstructions of the static scene and also recover the 3D trajectories of moving objects.