基于DPC算法的星载激光雷达数据去噪方法 在水深测量中的应用

Application of DPC algorithm-based denoising method for satellite-bornelidar data to bathymetry

中文关键词:  ICESat-2卫星  光子去噪  水深测深  DPC算法  基尼指数

英文关键词:ICESat-2 laser satellite  photonic denoising  hydrographic survey  DPC algorithm  Gini index

中文摘要:

      美国冰、云和陆地高程二号卫星 （The Ice，Cloud，and Land Elevation Satellite-2，ICESat-2） 是 ICESat卫星的继任者，旨在监测地球的冰盖、冰川、海洋和陆地高程的变化等，其携带的地形激光高度计系统 （ATLAS） 发射532 nm波长的激光，具备一定的水体穿透能力。作为光子计数式激光雷达，ICESat-2的数据易 受外界环境影响而接收到大量噪声光子，导致光子数据密度分布不均匀。本文提出了一种基于密度峰值聚类 （Density Peak Clustering，DPC） 算法的光子去噪方法，通过数据集的欧式距离计算局部密度作为点云数据的属 性，采用基尼指数自适应选择最优截断距离，分别对日间和夜间数据进行多次实验，得出了两类数据的局部密 度阈值参数。本文选取三处实验区域进行信号光子去噪分析，使用本文方法的去噪精度F值优于官方置信度标 签去噪和传统密度聚类算法 （Density-Based Spatial Clustering of Applications with Noise，DBSCAN），可以应用于 星载激光雷达数据去噪处理。最后，对去噪后的华光礁区域信号光子进行折射校正，与收集的DEM数据进行对 比可见，结合本文去噪方法可以使用ICESat-2数据进行浅水域的水深测量。

英文摘要:

      The U.S. Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2), succeeding the ICESat satellite, is designed to monitor changes in Earth's ice caps, glaciers, oceans, and land elevation. It carries the Advanced Topographic Laser Altimeter System (ATLAS), emitting a 532 nm laser that penetrates water bodies to a certain extent. As a photon-counting LiDAR system, ICESat-2's data is susceptible to external environmental factors, leading to the reception of numerous noisy photons, resulting in uneven photon data distribution. In this paper, we propose a photon denoising method based on the Density Peak Clustering (DPC) algorithm. It calculates local density as a point cloud data attribute using the Euclidean distance within the dataset. The optimal truncation distance is adaptively selected using the Gini index. We conduct experiments on daytime and nighttime data to derive threshold parameters for local density in both data types. We selected three experimental areas for signal photon denoising analysis. The denoising accuracy F-value using this method surpasses official confidence label denoising and the denoising clustering algorithm(DBSCAN), making it suitable for satellite-borne LiDAR data denoising. Finally, whencomparing the refraction correction of denoised signal photons in the Huaguang Reef area with collected DEM data, we find that our denoising method can effectively enable bathymetry measurements in shallow waters using ICESat-2 data.