Capturing city-level scenes with a synchronized camera-laser fusion sensor

In this paper, we present a sensor fusion system of cameras and 2D laser sensors for 3D reconstruction. The proposed system is designed to capture data on a fast-moving ground vehicle. The system consists of six cameras and one 2D laser sensor. In order to capture data at high speed, we synchronized all sensors by detecting the laser ray at a specific angle and generating a trigger signal for the cameras. Reconstruction of 3D structures is done by estimating frame-by-frame motion and accumulating vertical laser scans. The difference between the proposed system and the previous works using two 2D laser sensors is that we do not assume 2D motion. The motion of the system in 3D space (including absolute scale) is estimated accurately by data-level fusion of images and range data. The problem of error accumulation is solved by loop closing, not by GPS. The moving objects are detected by utilizing the depth information provided by the laser sensor. The experimental results show that the estimated path is successfully overlayed on the satellite images.