Lidar-Based DEM Thinning Algorithm

Airborne LiDAR(Light Detection And Ranging) technology provides a new survey tool for high density and high accuracy terrain data acquisition. There has been a significant concern in the use of high density and high accuracy LiDAR data for DEM generation. However, in most case, it can meet production requirements without large data sets for a specific application. And high density data lead to challenge with data post-processing software, hardware and efficiency. So how to thin LiDAR-based DEM effectively, such as balancing data compression rate and DEM accuracy, getting a more manageable and operationally DEM is important in engineering. Based on this objective, this paper mainly studies the following content:1. Describes the history of airborne LiDAR systems, system components, scanning mode and classification of LiDAR systems. On this basis, the main features of airborne LiDAR data are summarized, especially the mass of data. Because of the mass of LiDAR data makes LiDAR-based DEM has this feature. This is also the institute of this paper.2. The definition of DEM and the main DEM models are introduced in this paper, and the discrete point model is original model of LiDAR-based DEM. This paper also introduces LiDAR data filtering algorithms.3. LiDAR-based DEM thinning algorithms are researched and summarized especially in this paper, the advantages and disadvantages of the present algorithms are discussed. Based on this, a new Lidar-based DEM thinning algorithm is brought forward based on slope, and Lidar-based DEM thinning algorithm based on TIN is improved too.4. The DEM accuracy evaluation method is analyzed. The experiments are carried out using various LiDAR-based DEM thinning algorithms. The results of experiments show that thinning algorithm based on slope can better keep information on terrain features, and the precision of improved algorithm based on TIN better than the original thinning algorithm.In this paper, data reduction must be considered accuracy, cost and purpose of the final application. By experimental various thinning algorithm, the advantages and disadvantages of various algorithms and engineering application for which purpose are discussed in detail, and this has certain practical value in some engineering. The results of experiments show that thinning algorithm based on slope and improved thinning algorithm can keep better information on terrain features.