Rapid Virtual Object Development Using Photogrammetric Imagery Obtained with Small Unmanned Aircraft Systems Applications for Disaster Assessment and Cultural Heritage Preservation

Disaster assessment and cultural heritage preservation efforts can be enhanced by using small unmanned aircraft systems (sUAS) to obtain vantage points that were impossible in the past with manned aircraft. Imagery remotely sensed, during sUAS flight, can be processed using photogrammetric techniques to develop three dimensional (3D) virtual objects and two dimensional (2D) orthomosaic maps that can aid in inspecting, documenting and chronicling locations of interest. The basic premise of photogrammetry is the art and science of obtaining useful information from the environment by processing imagery and then applying exacting measures that can provide 3D characteristics. Photogrammetric software identifies keypoints among overlapping images and enables development of virtual objects. Photogrammetric software calculates parallactic displacement of recognized key

points and then assigns x, y and z values to identified pixels. These pixels serve as the basis for triangle mesh development and refinement as 3D virtual objects. The authors applied techniques to rapidly develop virtual objects during post wildfire disaster assessment and documentation of cultural heritage locations during the summer of 2018.