Rail Sensor: A Mobile Lidar System for 3D Archiving the Bas-reliefs in Angkor Wat

This paper presents a mobile Lidar system for efficiently and accurately capturing the 3D shape of the Bas-reliefs in Angkor Wat. The sensor system consists of two main components: 1) a panoramic camera and 2) a 2D 360-degree laser line scanner, which moves slowly on the rails parallel to the reliefs. In this paper, we first propose a new but simple method to accurately calibrate the panoramic camera to the 2D laser scan lines. Then the sensor motion can be estimated from the sensor-fused system using the 2D/3D features tracking method. Furthermore, to reduce the drifting error of sensor motion we adopt bundle adjustment to globally optimize and smooth the moving trajectories. In experiments, we demonstrate that our moving Lidar system achieves substantially better performance for accuracy and efficiency in comparison to the traditional stop-and-go methods.