Tree Diameter At Breast Height Measurement By Laser On Vehicles

In woodland information measurement,the measurement of tree DBH is an important link.Tree DBH is an important data standard for evaluating the quality,growth and management of woodland.In the current DBH measurement of trees,manual measurement is still the main method,which is not only inefficient,but also difficult to ensure the measurement accuracy.In order to reduce labor intensity and measurement cost,it is imperative to introduce automatic measurement.This paper focuses on urban parks and other woodlands,and designs the vehicle DBH measurement system according to its characteristics.In the target forest,the diameter measuring system is divided into two parts:measuring system and moving system.The mobile system needs to acquire the woodland environment,identify the position of trees,and independently plan the safe driving route,while the measuring system acquires the DBH of the target trees.In this paper,lidar is used as the point cloud acquisition equipment for trees,and lidar and depth camera are used as the navigation equipment to realize the DBD detection of trees in urban parks and other woodlands and the autonomous navigation of robots in woodlands.The main research contents are as follows:(1)The point cloud data and distance information of trees were obtained by using the lidar to obtain the woodland environment information,and the point cloud data were clustered by the density-based DBSCAN clustering algorithm.The point cloud clusters were marked,and the effective data clusters and invalid data clusters were divided.The DBH algorithm was applied to the data in the effective data clusters to calculate the DBH of the trees.Aiming at the disadvantage that DBSCAN clustering algorithm is sensitive to distance threshold and neighborhood sample threshold,the global threshold parameters are improved to dynamic threshold parameters obtained according to the distance from the point to the lidar,so that the clustering accuracy of the algorithm for point cloud data with different distances and densities is higher.(2)The key of autonomous path planning in forestland is location and navigation.The mobile system obtained the environmental distance information and the mileage data of the mobile system through the lidar and depth camera,and used the adaptive monte carlo positioning method to obtain the position and pose of the mobile system in the two-dimensional map.After the positioning of the mobile system is completed,the target point is sent to the mobile system,and the mobile system will independently plan a safe path to reach the target point.