3D cave mapping with handheld and terrestrial laser scanning

Author: Tommaso Santagata

在意大利北部，在雷吉奥·埃米利亚（Reggio Emilia）的阿本尼（Apennine）地区是“塔娜·德拉·穆西纳（Tana Della Mussina）”，这是一个以盖塔诺·基里奇（Gaetano Chierici）在1872年发掘中发现的考古文物而闻名的洞穴。作为当地洞穴小组的研究项目的一部分 -GSPGC- the virtual Geographic agency Vigea recently 3D scanned the entrance part of this cave system using theLeica BLK2GO, a handheld imaging laser scanner.

Mobile scanning allowed a team led by Tommaso Santagata from Vigea to map more of the cave than in previous surveys, thanks to the equipment’s smaller size, lighter weight and fast scanning speeds. This technique has the potential to allow cave researchers to capture 3D detail in challenging sites.

3D mapping the Tana della Mussina

The project was organised by the GSPGC caving group and theFSRER屈服。自1967年以来,GSPGC生产ed out exploration, research and study of the underground world in Italy and internationally. The group has discovered and explored numerous caves, often of considerable development and depth. They take part in many exploratory and research collaborations with most Italian speleological (cave study) groups, both regionally and nationally.

The Tana della Mussina is part of the Cà Speranza-Mussina cave system, which itself is part of the Messinian gypsum (dated between 5.6 and 6 million years old). The gypsum developed with a series of discontinuous chalky outcrops characterised by the presence of several sinkholes, in many cases occluded by landslides of clay and marl, which drain the surface waters feeding karst systems. Karst is an area of land formed of soluble rocks such as limestone, dolomite, and gypsum. Gaetano Chierici’s excavation of the cave in 1872 found human remains from the Aeneolithic period (third millennium BC) and ceramic, flint and copper artefacts.

Terrestrial Laser Scanning vs mobile mapping in cave systems

陆地激光扫描（TLS）仪器越来越多地用于3D地图自然和人工洞穴进行研究，提供了高度准确的细节。但是，并非总是可以创建完整的地图。地下环境本质上是具有挑战性的，通过狭窄和低通道可能难以进入，可能含有高水位，其寒冷温度使研究变得困难。

“There are sometimes limitations in the use of laser scanners which require tripods, or to be held in difficult positions to work safely, compromising the possibility of 3D scanning some complete cave environments. Handheld imaging laser scanners are newer instruments able to provide a 3D point cloud of the environment while walking. This kind of technology can be used for the almost complete capture of cave systems thanks to the possibility of moving much more comfortably and detecting in faster times,” Santagata explains.

Testing the BLK2GO handheld imaging scanner in Tana della Mussina

作为GSPGC和FSRER项目的一部分，Tana Della Mussina是2019年和2020年3D扫描调查的对象。在第一次调查中，使用A洞穴进行了3D扫描Leica ScanStation P40survey-grade, high-definition 3D laser scanning solution and the BLK2GO, a handheld, wireless, and lightweight imaging laser scanner. The data acquired was processed to create topographic maps. In June 2020, the BLK2GO scanner was tested with the objective to 3D scan the same part of the cave already mapped in the previous campaign.

Santagata解释了映射过程：“与惯性测量单元（IMU）集成在一起，BLK2GO允许我们进入3D地图并获取RGB数据信息以获得彩色的3D点云。当您移动时，BLK2GO将重新创建3D空间。与iPhone配对并使用Leica Geosystems的专用应用程序，它使我们能够实时查看结果的预览并控制乐器，并可能获取照片并添加在导出点云中查看的地理标签。”

Future of cave scanning – combining instruments for freedom and high definition

Santagata反思了该项目的成功以及在洞穴场景中移动映射的潜力，“ 3D激光扫描技术中的新创新可以带来斑方学的进展，尤其是通过使用便携式映射系统。诸如BLK2GO之类的手持移动映射工具能够从传统的激光扫描仪系统（可以保证更精确和更高的定义）中获取不同的细节，从而使我们能够在具有更多自由的地下环境中检测到3D。”

And crucially, through the integration of different systems, it is possible to obtain greater detail in the areas of interest using a terrestrial laser scanner and get a rapid global mapping of the environment in a short time with handheld systems - an ideal result.”

Explore the projects in 3D:
Test in Cave
内部数据详细说明from Valerio Brunelli
数据详细说明from Valerio Brunelli

Key people involved in the project: Tommaso Santagata (Vigea - Virtual Geographic Agency), Valerio Brunelli (Leica Geosystems Italy) and Stefano Bergianti (Gruppo Speleologico Paletnologico Gaetano Chierici di Reggio Emilia).

进一步阅读：
De Waele，J.，Fabbri，S.，Santagata，T.，Chiarini，V.，Columbu，A.，Pisani，L。（2018）石膏洞中使用陆生激光扫描和3D摄影测量法（意大利Emilia Romagna）中的几何形态和棘突遗传学观测。地貌学，319，47-61。