Indoor Photogrammetry Using Uavs With Protective Structures: Issues and Precision Tests

Abstract

<p><strong>Abstract.</strong> Management of disaster scenarios requires applying emergency procedures ensuring maximum safety and protection for field operators. Actual conditions of disaster sites are labelled as “Triple-D: Dull, Dusty, Dangerous” areas. It is well known that in this kind of areas and situations remote surveying systems are at their very best effective, and among these UAVs currently are an effective and performing field tool. Indoor spaces are a particularly complex scenario for this kind of surveys. In this case, technological advances currently offer micro-UAV systems, featuring 360° protective cages, which are able to collect video streams while flying in very tight spaces. Such cases require manual control of the vehicle, with the operator piloting the aircraft without prior knowledge of the status quo of the survey object and therefore without prior planning of flight paths. A possible benefit in terms of knowledge of the survey object could lay in the creation of a 3D model based on images extracted by video streams; to date, widely tested methods and techniques are available for processing UAV-borne video streams to obtain such models. Anyway, the protective cage and the need to use, in these operating conditions, wide-angle lenses presents some issues linked to ever-changing image framing, due to the presence of the cage wires on the field of view. The present work focused on this issue. Using this type of UAVs, video streams have been collected in different environments, both indoors and outdoors, testing several procedures for photogrammetric processing in order to assess the ability to create 3D models. These have been tested for reliability based on data collection conditions, also assessing the level of automation and speed attainable in post-processing. The present paper describes the different tests carried out and the related results.</p>

Survey Solutions for 3D Acquisition and Representation of Artificial and Natural Caves

“…Moreover, the increment of RPAS datasets is additionally broadening the potential application of such an approach [52,53]. Although these systems were initially implemented to acquire data in extensive outdoor environments, there are now many recent studies that describe their applicability in indoor spaces [54,55], even in dark caves [56]; in this last case, proposed solutions are mainly employed for the survey of small portions of the natural cave [57] and not for extensive surveys.…”

From survey to semantic representation for Cultural Heritage: the 3D modeling of recurring architectural elements

“…For a detailed description of the different types of survey used, please refer to [47]; the choice of the type of technique depended on the level of detail and restitution required, as well as on the complexity of the environment to be surveyed. In general, laser scanning enriched the ground measurements for the accurate restitution of elevation walls, plans and sections of the complex at 1:100 scale and of some significant portions at 1:50 scale (Figure 2 and Figure 3).…”

“…Aerial photogrammetry using unmanned aerial vehicles was undertaken to represent parts that were not directly visible or inspectable, such as roofs, wells and underground tanks, as previously described in [48], [49]. The different acquisitions were all georeferenced with respect to a single reference system, called 'Charterhouse reference system', which was set up through the construction of a network of benchmarks [47].…”

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