A novel 3D laser scanner design for variable density scanning

The perception systems in mobile robotics use large variety of sensors, however, the most reliable are vision systems and laser scanners. Among the laser scanners, one of the most popular are the lidars using multiple laser range finders (LRF). They emit a set of 16, 32, 64 or 128 laser beams with different elevation angle. The set of beams can rotate around the vertical axis providing different azimuths. This design causes a very good horizontal resolution but very poor vertical resolution. Moreover, while scanning from stationary position, these scanners get always the same points because each laser beam is emitted always in the same direction. Due to these facts, typical mobile robot tasks like robot localization, mapping, object recognition and collision avoidance, can easily fail. In this paper we present a design of a new 3D laser scanner using a single laser range finder and two optical elements rotating around the same axis. Our design ensures significantly bigger vertical resolution than currently available 3D scanners and provides possibility of increasing point cloud density. Although it uses only a single LRF and provides smaller measurement frequency, our research proved that it can be successfully used in mobile robot localization and mapping. We present the design in two versions - wide and narrow field-of-view (FOV).