UAV-Based Photogrammetry and Integrated Technologies for Architectural Applications—Methodological Strategies for the After-Quake Survey of Vertical Structures in Mantua (Italy)

Abstract

This paper examines the survey of tall buildings in an emergency context like in the case of post-seismic events. The after-earthquake survey has to guarantee time-savings, high precision and security during the operational stages. The main goal is to optimize the application of methodologies based on acquisition and automatic elaborations of photogrammetric data even with the use of Unmanned Aerial Vehicle (UAV) systems in order to provide fast and low cost operations. The suggested methods integrate new technologies with commonly used technologies like TLS and topographic acquisition. The value of the photogrammetric application is demonstrated by a test case, based on the comparison of acquisition, calibration and 3D modeling results in case of use of a laser scanner, metric camera and amateur reflex camera. The test would help us to demonstrate the efficiency of image based methods in the acquisition of complex architecture. The case study is Santa Barbara Bell tower in Mantua. The applied survey solution allows a complete 3D database of the complex architectural structure to be obtained for the extraction of all the information needed for significant intervention. This demonstrates the applicability of the photogrammetry using UAV for the survey of vertical structures, complex buildings and difficult accessible architectural parts, providing high precision results.

Open Source and Independent Methods for Bundle Adjustment Assessment in Close-Range UAV Photogrammetry

“…In its role as an aid to photogrammetric work, the UAV has been applied in various fields, such as disaster management [14,30], 3D building reconstruction [31], surveying/mapping [32], environmental conservation [18] and heritage documentation [15,33].…”

“…This includes the development of image feature matching [11] that enables the automatic extraction and matching of tie points. Similarly, improvements in dense matching algorithms [12,13] have rendered the photogrammetric process very powerful, enabling it to produce dense point clouds up to one point per pixel [14]. In photogrammetry, UAVs (Unmanned Aerial Vehicles) have provided the means to capture images at close ranges, but from aerial points of view.…”

Comparing Multi-Source Photogrammetric Data During the Examination of Verticality in a Monumental Tower

“…al, 2004. Photogrammetric methods are also used (Achille et al, 2015;Mass and Hampel, 2006;Bernasik and Mikrut, 2007). Laser scanning methods are becoming more popular, as they allows for the spatial determination of locations involving big sets of points on the surface of a slender object (Danilo et al, 2006;Fidera et al, 2004).…”

Structure from motion (SfM) processing of UAV images and combination with terrestrial laser scanning, applied for a 3D-documentation in a hazardous situation

“…Terrestrial laser scanning (TLS) integrates UAV-borne photogrammetry surveys carried out with horizontal flight by providing point clouds documenting geometries lying mainly on vertical planes (Achille et al 2015). The present work contributes in this field.…”