Identifying bare-earth or ground returns within point cloud data is a crucially important process for archaeologists who use airborne LiDAR data, yet there has thus far been very little comparative assessment of the available archaeology-specific methods and their usefulness for archaeological applications. This article aims to provide an archaeology-specific comparison of filters for ground extraction from airborne LiDAR point clouds. The qualitative and quantitative comparison of the data from four archaeological sites from Austria, Slovenia, and Spain should also be relevant to other disciplines that use visualized airborne LiDAR data. We have compared nine filters implemented in free or low-cost off-the-shelf software, six of which are evaluated in this way for the first time. The results of the qualitative and quantitative comparison are not directly analogous, and no filter is outstanding compared to the others. However, the results are directly transferable to real-world problem-solving: Which filter works best for a given combination of data density, landscape type, and type of archaeological features? In general, progressive TIN (software: lasground_new) and a hybrid (software: Global Mapper) commercial filter are consistently among the best, followed by an open source slope-based one (software: Whitebox GAT). The ability of the free multiscale curvature classification filter (software: MCC-LIDAR) to remove vegetation is also commendable. Notably, our findings show that filters based on an older generation of algorithms consistently outperform newer filtering techniques. This is a reminder of the indirect path from publishing an algorithm to filter implementation in software.

中文翻译：

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从机载LiDAR点云提取考古专用地面滤波器的比较

对于使用机载LiDAR数据的考古学家来说，识别点云数据中的裸露或地面回波是至关重要的过程，但是迄今为止，对可用的特定于考古的方法及其在考古应用中的实用性的比较评估很少。本文旨在为从机载LiDAR点云中提取地面的滤波器提供特定于考古的比较。来自奥地利，斯洛文尼亚和西班牙的四个考古遗址的数据的定性和定量比较也应该与使用可视化机载LiDAR数据的其他学科相关。我们比较了免费或低成本现成软件中实现的九种过滤器，其中有六种是首次以这种方式进行评估。定性和定量比较的结果不是直接相似的，并且与其他过滤器相比，没有出色的过滤器。但是，结果可以直接转移到现实世界中解决问题的方法：对于给定的数据密度，景观类型和考古特征类型的组合，哪种滤波器最有效？通常，渐进式TIN（软件：lasground_new）和混合（软件：Global Mapper）商业过滤器始终是最好的，其次是基于开源斜率的过滤器（软件：Whitebox GAT）。免费的多尺度曲率分类过滤器（软件：MCC-LIDAR）去除植被的能力也值得赞扬。值得注意的是，我们的发现表明，基于较老一代算法的过滤器始终优于新型过滤技术。