3D reconstruction of caves : an analysis of existing low-cost reconstruction alternatives and their application process

Abstract

Caves are complex environments from a spatial point of view and modeling and graphically representing them is not a trivial task. 3D models are often needed to research, record, and represent these environments. Recently, with the use of laser scanning systems, it has become possible to obtain reliable 3D representations of caves. However, the high costs and difficult acquisition of the equipment needed limit the possibilities of its use in Brazil. Considering the speleological potential of the country, being able to carry out low-cost 3D reconstructions of natural underground cavities would allow the expansion of the documentation of caves in the Brazilian territory, adding new possibilities such as precise calculations of volume and area. The three-dimensional products would also serve multiple purposes, such as environmental licensing and ecotourism, among others. This dissertation presents an analysis of three existing affordable reconstruction alternatives using the iPhone 13 Pro Max and the Intel RealSense L515 camera. The reconstructions obtained with each alternative and the application process for data capturing, processing, visualization, and area and volume estimations are presented. The three low-cost reconstruction techniques demonstrated potential for reconstructing small-scale caves and specific objects/features inside them, being the iPhone 13 Pro Max’s built-in LiDAR scanner approach the most time efficient and simple to use. However, the limited capture range of all the sensors tested does not allow capturing very distant objects, so the reconstruction of big-size caves may not be possible with the presented approaches. Considering the results of this dissertation, new research opportunities arise, like testing the proposed step-by-step pipelines in different caves, amongst others.