Using Smart Phones for Deformations Measurements of Structures

Abstract

The present work tests the suitability of using the digital cameras of smart phones for close range photogrammetry applications. For this purpose two cameras of smart phones Lumia 535 and Lumia 950 XL were used. The resolutions of the two cameras are 5 and 20 Mpixels respectively. The tests consist of (a) self calibration of the two cameras, (b) the implementation of close-range photogrammetry using the cameras of the two smart phones, theodolite intersection with LST method, and linear variable displacement transducers (LVDTs) for the measurement of vertical deflections, and (c) accuracy of photogrammetric determination of object space coordinates. The results of using Lumia 950 XL are much better than using Lumia 535 and are better or comparable to the results of theodolite intersection with least squares technique (LST). Finally, it can be stated that the digital cameras of smart phones are suitable for close range photogrammetry applications according to accuracy, costs and flexibility.

Geometric Evaluation of Mobile-Phone Camera Images for 3D Information

“…e Agisoft PhotoScan Professional software package (version 1.4.3; Agisoft, 2018) was used to generate a 3D photorealistic model of the historical structure based on SfM and MVS algorithms. e workflow of the software for 3D modeling comprised four primary steps: (1) align photos, (2) optimization, (3) build dense point cloud, and (4) surface reconstruction (3D polygonal model).…”

“…e main difference between compact and professional cameras is the lower geometric stability of amateur cameras. Among the different amateur cameras, smartphone cameras are the most interesting option because mobiles phones are light, portable, inexpensive, and fully equipped with highresolution digital cameras [2,3]. e camera calibration is a process required to extract accurate and reliable 3D information from images.…”

“…With the advent of high-resolution mobile-phone cameras in the 2010s, these devices have begun to be used as imaging tools in photogrammetric tasks. A few studies have focused on the use of smartphone camera images for pure photogrammetric processes, e.g., in the work of El-Ashmawy et al [2]. e authors used mobile-phone camera images to photogrammetrically determine the displacements of signalized points on a beam under loading.…”

Monitoring Bridge Dynamic Deformation Law Based on Digital Photography and Ground-Based RAR Technology

“…Ivan Detchev et al [21] combined digital cameras with image processing technology to propose novel sine-wave curve fitting based on the least-square method, which enhanced measurement accuracy and frequency. Khalid L. A et al [22] explored the feasibility of smart phones in the deformation monitoring field; using two smart phones, namely LAmia535 and SLAmia 950 XL, vertical displacement was measured. The experiment indicates that smart phones can meet the requirements of digital close-range photogrammetry in regard to precision, cost, and flexibility.…”