Research Of Constructing High-accuracy Dsm Using Airborne Lidar Points

LiDAR is an effective technology for acquisition of altitude information, which is an active measurement instrument for processing high accuracy and high density three dimensional data. The terminology of airborne LiDAR refers to an airborne laser system consisting of a laser scanner, a geodetic quality GPS receiver and an inertial measurement unit (IMU), which less depends on ground controls, little affected by weather conditions with high automation and short temporal data processing. The LiDAR system has made the data collecting effectively, which can effectively get accurate and higher-resolution digital surface model. LiDAR technology converts the data acquisition method from the traditional mode based on forward intersection into a consistent and automatic mode. LiDAR can also make the data processing more intelligent and automatic than before.This article reviews the technology of airborne laser scanning and current literature of data processing using LiDAR system, then introduces the LiDAR range measurement principles, characteristic, and applicable scope of LiDAR system. Based on the comprehension and analysis the theorem and characteristics of LiDAR system and review the key technology in DSM producing with LiDAR points. The main contents are as follows:1. This article reviews the development history, current and future research of data processing of LiDAR system, then summarizes the development status and challenge of LiDAR, and points out the hotspot and difficulty in LiDAR; Gives a detailed introduction of ranging theory, and compares airborne LiDAR technology with photogremmetry and terra-based laser scanners. Then introduces the applications of the airborne LiDAR.2. Summarizes and analysis on the method of removing outlies, and designs a semi-automatic method to remove the temporary coverings, and provide a favorable data source for the production of DSM. Summarizes the methods of breakline acquisition, and proves that it's necessary to use breakline for high precision DSM.3. Develops a formula according to the principle of LiDAR ranging, and then acquires the best interpolation algorithm and interpolation size for DSM from the experiment.4. The traditional hill-shading theory is applied for visualization of DSM, and proposes two methods by the further study on the Shading theory. One is based on elevation Histogram, while the other one is based on the classification of mass points.