Accurate scale estimation based on unsynchronized camera network

In this paper we present an unsynchronized camera network able to estimate the motion and the structure with accurate absolute scale. The proposed algorithm requires at least three frames: two frames from one camera and a frame from a neighbouring camera. The relative camera poses are estimated with classical Structure-from-Motion and the absolute scales between views are computed by assuming straight trajectories between consecutive views of one camera. We propose a final optimisation step to refine only the scale and the 3D points. Our method is evaluated in real conditions on the KITTI dataset. We show quantitative evaluation through comparisons against GPS/INS ground truth.