Resolving ranges of layered objects using ground vehicle LiDAR

Lidar systems are well known for their ability to measure three-dimensional aspects of a scene. This attribute of Lidar has been widely exploited by the robotics community, among others. The problem of resolving ranges of layered objects (such as a tree canopy over the forest floor) has been studied from the perspective of airborne systems. However, little research exists in studying this problem from a ground vehicle system (e.g., a bush covering a rock or other hazard). This paper discusses the issues involved in solving this problem from a ground vehicle. This includes analysis of extracting multi-return data from Lidar and the various laser properties that impact the ability to resolve multiple returns, such as pulse length and beam size. The impacts of these properties are presented as they apply to three different Lidar imaging technologies: scanning pulse Lidar, Geiger-mode flash Lidar, and Time-of-Flight camera. Tradeoffs associated with these impacts are then discussed for a ground vehicle Lidar application.