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.

Keywords:

• smart phones
• close range photogrammetry
• self calibration block adjustment
• deflection
• intersection with least squares technique (LST)

Additional information

Notes on contributors

Khalid L. A. El-Ashmawy

Khalid L. A. EL-ASHMAWY (Dr) is associate professor of Surveying & Digital Mapping at the Department of Civil Engineering, Al-Matria Faculty of Engineering, Helwan University, Egypt. His area of expertise includes photogrammetry, land surveying, space photography, digital mapping, GIS and development of surveying softwares.

Dr Khalid El-Ashmawy developed many surveying softwares which were published in national and international journals and conferences, such as SoftPhotoMap, PHOTOMAP, MATHP, ScanCal, LandSurMap, Calendar, RSA (Road Safety Assessment), and MathDTM softwares.