Camera-based close-range coordinate metrology

Sims-Waterhouse, Danny (2020) Camera-based close-range coordinate metrology. PhD thesis, University of Nottingham.

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Abstract

The main focus of this thesis was on the development of techniques and methodologies to allow the effective application of photogrammetry to coordinate metrology. The current understanding of the propagation of uncertainty through camera-based measurement systems is limited due to the highly complex and non-linear nature of the techniques. Additionally, the application of existing verification standards is unclear and difficult to apply directly to high-accuracy photogrammetry systems. The aim of this work was, therefore, to develop techniques to evaluate the coordinate measurement uncertainty of photogrammetry systems as well methods that allow existing verification standards to be effectively applied.

Based on Monte Carlo simulations, an evaluation of the contributing factors to the expanded uncertainty on measurements made by a stereo photogrammetry system was performed. A traceable scaling methodology was also applied to the stereo system, allowing the identification of the key contributing factors to the stereo system measurement to be highlighted and targeted for future. Additionally, the effect of systematic errors on the measurement volume was simulated and then verified through experimental observations.

A laser speckle texture projection methodology was also developed in order to allow existing verification standards to be applied to conventional photogrammetry systems. By projecting artificial texture onto the verification artefact surface, the verification outlined in the VDI/VDE 2634 part 3 standards were applied. The results of the verification tests demonstrated the high levels of accuracy that can be achieved by photogrammetry based coordinate measurement systems.

Through the use of fringe projection techniques, an additional method of applying verification standards to a stereo photogrammetry system was also performed. By using phase encoding to find correspondence between cameras, the verification tests were applied and were in agreement with predicted values. Additionally, the use of phase encoded correspondence also presents a promising method to vastly improve the accuracy of the characterisation of stereo system properties.

Finally, the principles of photogrammetry were applied to several case studies. The photogrammetry principles developed in this thesis were used to develop data fusion methods to greatly improve the bandwidth of measurements, use laser speckle to produce material agnostic measurements of part geometry and calibrate reconstruction scale factors using light-field imaging principles.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Leach, Richard
Piano, Samanta
Keywords: Photogrammetry; Metrology; Laser speckle;
Subjects: T Technology > TR Photography
Faculties/Schools: UK Campuses > Faculty of Engineering
Item ID: 60677
Depositing User: Sims-Waterhouse, Danny
Date Deposited: 24 Jul 2020 04:40
Last Modified: 24 Jul 2020 04:40
URI: https://eprints.nottingham.ac.uk/id/eprint/60677

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