使用全波形激光雷达从丛林中拉出伪影

Author:Penny Boviatsou

高棉帝国的伟大及其作为柬埔寨文化遗产的一部分的重要性刚刚开始展开。有史以来在考古项目上开展的最广泛的空降激光扫描运动揭示了埋葬在柬埔寨丛林中的古老城市。

Lidar被证明是更好地了解我们历史的催化剂。创新技术正在改变考古学，并迅速成为考古学家的强大工具。激光可以穿透上覆的植被，并且覆盖地面的速度比步行得多的速度要快。

The Angkor complex is one of the most important archaeological sites in Siem Reap in Southeast Asia and the Angkor Wat one of the world’s most recognisable temples. In the late 12th and early 13th centuries the city was at its peak with historians describing an urban centre extending over nearly 1036 square km. Angkor was the centre of a once massive and powerful nation believed to be the largest in the world at the time, with up to 1 million inhabitants.

隐藏但没有忘记

没有什么能像丢失的大都市的前景那样引起研究人员的想象力。经过多年的研究，柬埔寨的考古学家最近宣布发现了在吴哥附近的热带森林地板和柬埔寨王国的其他考古遗址下发现的多个中世纪城市。巨大的发现挑战了盎格鲁人民最终放弃南部城市的理论，直到最近才相信。由于空降激光扫描技术，考古学家能够发现失去文明的废墟：

• The Khmer Archaeology LiDAR Consortium (KALC) in April 2012 and the
• 柬埔寨考古LiDAR倡议（CALI）于2015年4月决定扩展到高棉历史和考古学的传统方法之外的观点。

Both projects were designed by Francisco Gonçalves and Chris Cromarty from PT Map Tiga Internasional (PTMI - formerly PT. McElhanney Indonesia), a Jakarta-based company providing aerial mapping and surveying expertise.

这些项目的前提是，LiDar可以提供隐藏在树冠下的关键信息，以充分评估高棉文明在东南亚，特别是在柬埔寨的程度和影响。为了实现目标，弗朗西斯科·冈卡维斯（Francisco Goncalves），罗兰·弗莱彻（Roland Fletcher）教授和达米安·埃文斯（Damian Evans）博士之间的几个会议工具位置。这些使PTMI了解景观和植被挑战，在收购之前还计划了现场访问。

PTMI购买了Leica Geosystems的LiDAR和数字航空摄影传感器，为研究人员提供高分辨率的空中图像以及高密度地面LIDAR指向考古学家，同时扫描柬埔寨丛林。

The first findings came in 2012 when the company worked closely with Dr. Damian Evans and the Consortium’s associates. By flying a helicopter mounted with a POD carrying, a Leica LiDAR scanner equipped with waveform data capture and a Leica digital aerial camera, PTMI gathered data that confirmed the existence of Mahedraparvata, an ancient temple city whose existence had been known for decades.

最近分析的数据，于2015年捕获考古项目有史以来最广泛的空降研究, uncovered the total scale of the Khmer Empire’s urban extent and found the temple complexes to be extremely greater than was previously believed.

“LiDAR generated maps revealed multiple medieval cities hidden on the forest floor and upended what we knew about the lived-in spaces around Angkor and other temple complexes across Cambodia,” said Dr Damian Evans. “The vegetation was obscuring these monumental sites. The LiDAR technology allowed us to see through the vegetation。”

Unveiling the secrets of an empire

In 2015, PTMI covered 1600 square km with the goal to deliver the Cambodia Archaeology LiDAR Initiative, the finest and most complete data coverage of their areas of interest, and provide an opening for future archaeology LiDAR investigation. At the planning stages of the project, PTMI spent approximately a year discussing approaches to the LiDAR and Digital Air Photo (DAP) acquisition.

弗朗西斯科·冈萨（FranciscoGonçalves）和克里斯·克罗马蒂（Chris Chromarty）步行了计划进行激光雷达和DAP采购的区域，并研究了树木覆盖下的地形和植被，以及激光雷达可能检测到的考古特征的类型。

“考古学使我着迷”says Francisco Gonçalves, President Director at PTMI.“隐藏了什么秘密，我们的祖先在其中建造了城市以及为什么放弃了城市。通过Leica Geosystems技术穿透柬埔寨丛林，我们能够获取LiDar Point数据，这些数据不仅揭示了土地景观的结构，还可以揭示结构，道路，运河，结构基础和农业露台。”

PTMI使用Leica Geosystems的LiDAR映射系统来扫描柬埔寨丛林。该公司使用LiDAR技术收集了数据，这些技术渗透到茂密的柬埔寨森林和茂密的植被，收集有关土壤表面和地形高程的信息，使考古学家能够在吴哥附近找到广泛的网络痕迹。数码航空摄影与LIDAR数据同时收集。

"Agricultural fields and other structures have remained hidden by growing trees for centuries, but LiDAR technology is changing the way we view the world," said Professor Roland Fletcher. "Cases of recently deforested lands challenge the theories that ancient forests are 'pristine ecosystems', people shaped the landscapes where forests are located for thousands of years."

所有LIDAR数据均使用安装在柬埔寨的AS350 B2直升机（Helistar）中的POD获取，然后使用配备配备DataPort可移动驱动器的处理站进行了调整和处理，PTMI调整和处理处理中心。PTMI计划了数据采集，调整了空气图像，并将激光雷达分为地面和非地点。所有结果都交付给了卡利，埃文斯和他的团队能够准备考古分析。

LIDAR - 考古学的新工具

激光雷达的能力穿透茂密的植被meant that the temple complexes and surrounding areas are able to be seen clearly for the first time since the habitation period. With LiDAR-generated maps, subtle topographical changes have traced out road networks, occupation mounds and other urban planning signs that were previously undetectable even from the ground.

The LiDAR-made maps enable the CALI researchers to make more targeted excursions at the site whilst the LiDAR data determine the locations where further research might be useful.

考古领域的研究人员认为，这些是近年来最重要的考古发现。