02/16/2024
By Danielle Fretwell

The Francis College of Engineering, Department of Mechanical Engineering, invites you to attend a Doctoral Dissertation Proposal defense by Fabio Bottalico on "Development of a UAV-Borne Stereophotogrammetry System for Dynamic Measurements on Large-Scale Str."

Candidate Name: Fabio Bottalico
Degree: Doctoral
Defense Date: Thursday, Feb. 29, 2024
Time: 10:30 a.m. to noon
Location: BAL-313

Committee

  • Advisor: Alessandro Sabato, Assistant Professor, Committee Chair, Mechanical Engineering, UMass Lowell
  • Co-Advisor: Christopher Niezrecki, Professor, Co-chair, Mechanical Engineering, UMass Lowell
  • Yan Luo, Professor, Electrical and Computer Engineering, UMass Lowell
  • Devin K. Harris, Professor, Civil and Environmental Engineering, University of Virginia

Brief Abstract:

The last decade has seen a significant increase in the use of computer vision techniques for structural dynamics and structural health monitoring as an alternative to traditional contact-based measurement methods. Stereophotogrammetry techniques, such as three dimensional-digital image correlation (3D-DIC) and three dimensional-point tracking (3D-PT) have been used to extract full-line-of-sight displacements and strain maps of structures by analyzing pictures taken with synchronized stereo cameras. Before performing any measurement, the stereo cameras must be calibrated to determine their relative position in the 3D space and high-contrast stochastic speckle patterns or optical targets must be applied on the surface of the structure to be inspected. Calibration requires a target whose dimensions are comparable to the structure to analyze, and the application of speckle patterns/optical targets necessitates the user to access the structure. Both requirements become obstacles that hinder the use of these computer vision techniques for performing analyses on large-scale structures such as bridges and wind turbines. This proposed research aims at improving the usability of stereophotogrammetry for large-scale structures by developing and testing i) an alternative calibration method that measures the cameras’ relative position using inertial measurement units (IMUs) and laser rangefinders, thus eliminating the dependency on a large calibration target; ii) an algorithm that tracks naturally occurring features with accuracy comparable to 3D-PT, thus eliminating the dependency to optical targets to be applied on the targeted structure, and iii) a novel calibration method to dynamically measure the cameras’ relative position and orientation, to enable stereophotogrammetry to be performed from movable platforms such as unmanned aerial vehicles.