3D cave mapping with handheld and terrestrial laser scanning

Author: Tommaso Santagata

In northern Italy, in the pre-Apennine area of Reggio Emilia is the "Tana della Mussina," a cave famous for archaeological artefacts found in excavations made in 1872 by Gaetano Chierici. As part of a research project with a local caving group - theGSPGC- 虚拟地理机构Vigea最近3D使用了该洞穴系统的入口部分Leica BLK2GO, a handheld imaging laser scanner.

移动扫描允许托马索·桑特领导的研究小组agata 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

该项目由GSPGC洞穴组和FSRER洞穴协会。自1967年以来，GSPGC一直对意大利和国际地下世界进行探索，研究和研究。该小组发现并探索了许多洞穴，通常是相当大的发展和深度。他们与大多数意大利的Speleological（Cave研究）小组一起参加了许多探索性和研究合作。

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

Terrestrial Laser Scanning (TLS) instruments are increasingly used to 3D map natural and artificial caves for study, providing a high level of accurate detail. However, it’s not always possible to create a complete map. Underground environments are challenging by nature, can be difficult to access through narrow and low passages, may contain high water levels and its cold temperatures make studies difficult.

“有时使用需要三脚架的激光扫描仪有局限性，或者在困难的位置安全工作，从而损害了3D扫描一些完整的洞穴环境的可能性。手持式成像激光扫描仪是较新的仪器，可以在步行时提供3D点云。由于可能更舒适地移动并在更快的时候检测到，这种技术可以用于几乎完全捕获洞穴系统。” Santagata解释说。

Testing the BLK2GO handheld imaging scanner in Tana della Mussina

As part of the GSPGC and FSRER project, Tana della Mussina was the object of 3D scanned surveys in 2019 and 2020. In the first survey, the cave was 3D scanned using aLeica 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 explains the mapping process, “Integrated with an Inertial Measurement Unit (IMU), the BLK2GO allowed us to 3D map and acquire RGB data information to obtain coloured 3D point clouds. The BLK2GO recreates spaces in 3D as you move. Paired with an iPhone and using Leica Geosystems’ dedicated application, it allowed us to view a preview of the results in real time and control the instrument, with the possibility of acquiring photographs and adding GeoTags to be viewed in the exported point clouds.”

洞穴扫描的未来 - 结合自由和高清工具

Santagata reflects on the success of the project and the potential for mobile mapping in cave scenarios, “New innovations in 3D laser scanning technology can bring progress in speleology, especially through the use of portable mapping systems. Handheld mobile mapping tools such as the BLK2GO are able to get different details from traditional laser scanner systems (which can guarantee much more precision and higher definition) allowing us to detect in 3D in underground environments with more freedom.”

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
Data Elaboration Inside来自Valerio Brunelli
数据详细说明来自Valerio Brunelli

关键人员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).

Further reading:
DE WAELE, J., FABBRI, S., SANTAGATA, T., CHIARINI, V., COLUMBU, A., PISANI, L.(2018)Geomorphological and speleogenetical observations using terrestrial laser scanning and 3D photogrammetry in a gypsum cave (Emilia Romagna, N. Italy). Geomorphology,319, 47-61.