Potentials of Low-Budget Microdrones: Processing 3D Point Clouds and Images for Representing Post-Industrial Landmarks in Immersive Virtual Environments

Abstract

Post-industrial areas in Europe, such as the Rhine-Ruhr Metropolitan region in Germany, include cultural heritage sites fostering local and regional identities with the industrial past. Today, these landmarks are popular places of interest for visitors. In addition to portable camera devices, low-budget ultra-lightweight unmanned aerial vehicles, such as micro quadcopter drones, are on their way to being established as mass photography equipment. This low-cost hardware is not only useful for recreational usage but also supports individualized remote sensing with optical images and facilitates the acquisition of 3D point clouds of the targeted object(s). Both data sets are valuable and accurate geospatial data resources for further processing of textured 3D models. To experience these 3D models in a timely way, these 3D visualizations can directly be imported into game engines. They can be extended with modern interaction techniques and additional (semantic) information. The visualization of the data can be explored in immersive virtual environments, which allows, for instance, urban planners to use low-cost microdrones to 3D map the human impact on the environment and preserve this status in a 3D model that can be analyzed and explored in following steps. A case example of the old wage hall of the Zeche “Bonifacius” (Essen, Germany) with its simple building structure showed that it is possible to generate a detailed and accurate 3D model based on the microdrone data. The point cloud which the 3D model of the old wage hall was based on represented partly better data accuracy than the point clouds derived from airborne laser scanning and offered by public agencies as open data. On average, the distance between the point clouds was 0.7 m, while the average distance between the airborne laser scanning point cloud and the 3D model was −0.02 m. Matching high-quality textures of the building facades brings in a new aspect of 3D data quality which can be adopted when creating immersive virtual environments using the Unity engine. The example of the wage hall makes it clear that the use of low-cost drones and the subsequent data processing can result in valuable sources of point clouds and textured 3D models.

RS-YOLOX: A High-Precision Detector for Object Detection in Satellite Remote Sensing Images

“…In some cases, manual methods of processing remote sensing data can also achieve good results. For example, Weißmann et al [58] collected data by controlling the drone, and then used related software to reconstruct the point clouds and textured 3D models of the survey objects. This study did not use a fully automated process, and many critical steps were performed manually, but according to these methods, photorealistic 3D models can be reconstructed.…”

Cartographic Representations of Coastal Land Loss in Louisiana: An Investigation Based on Deviant Cartographies

“…The net area lost is consisting of the difference between land gains and land losses (where there is a result from the deposition of flotsam, the realignment of existing marshes displaced by the storm surge). The measurement of gains and losses of land makes particular use of remote sensing methods (Weißmann et al 2022). In the positivist tradition of thought, it is assumed that there is indicative adequacy between what is depicted and what is depicting.…”

Volunteered Geographic Information

“…One way to combine methods of visualization and VR, as well as to implement analysis methods and make them available via a graphical user interface (GUI), is to use the Unity Game Engine (Helbig et al 2015). Its use in scientific projects has increased in recent years, e.g., for integration of 3D building model data (Keil et al 2021), visualizing 3D point clouds captured by drones (Weißmann et al 2022), implementing a walkable virtual city model (Schmohl et al 2020), and simulating secure hazardous transportation (Yang et al 2020). Another argument for the use of game engines is the possibility to integrate audio data in a straightforward way, which increases the degree of immersion considerably (Hruby 2019;Berger and Bill 2019;Rafiee et al 2017) and is not available in conventional visualization tools for geodata.…”