The Active Stereo Probe: The Design and Implementation of an Active Videometrics System

Urquhart, Colin W (1997) The Active Stereo Probe: The Design and Implementation of an Active Videometrics System. PhD thesis, University of Glasgow.

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This thesis describes research leading to the design and development of the Active Stereo Probe (ASP): an active vision based videometrics system. The ASP espouses both definitions of active vision by integrating structured illumination with a steerable binocular camera platform (or head). However, the primary function of the ASP is to recover quantitative 3D surface models of a scene from stereo images captured from the system's stereo pair of CCD video cameras. Stereo matching is performed using a development of Zhengping and Mowforth's Multiple Scale Signal Matcher (MSSM) stereo matcher. The performance of the original MSSM algorithm was dramatically improved, both in terms of speed of execution and dynamic range, by completely re-implementing it using an efficient scale space pyramid image representation. A range of quantitative performance tests for stereo matchers was developed, and these were applied to the newly developed MSSM stereo matcher to verify its suitability for use in the ASP. The performance of the stereo matcher is further improved by employing the ASP's structured illumination device to bathe the imaged scene in textured light. Few previously reported dynamic binocular camera heads have been able to perform any type of quantitative vision task. It is argued here that this failure has arisen mainly from the rudimentary nature of the design process applied to previous heads. Therefore, in order to address this problem, a new rigorous approach, suitable for the design of both dynamic and static stereo vision systems, was devised. This approach relies extensively upon system modelling as part of the design process. In order to support this new design approach, a general mathematical model of stereo imaging systems was developed and implemented within a software simulator. This simulator was then applied to the analysis of the requirements of the ASP and the MSSM stereo matcher. A specification for the imaging and actuation components of the ASP was hence obtained which was predicted to meet its performance requirements. This led directly to the fabrication of the completed ASP sensor head. The developed approach and model has subsequently been used successfully for the design of several other quantitative stereo vision systems. A vital requirement of any vision system that is intended to perform quantitative measurement is calibration. A novel calibration scheme was devised for the ASP by adopting advanced techniques from the field of photogrammetry and adapting them for use in the context of a dynamic computer vision system. The photogrammetric technique known as the Direct Linear Transform was used successfully in the implementation of the first, static stage of this calibration scheme. A significant aspect of the work reported in this thesis is the importance given to integrating the components developed for the ASP, i.e. the sensor head, the stereo matching software and the calibration software, into a complete videometric system. The success of this approach is demonstrated by the high quality of 3D surface models obtained using the integrated videometric system that was developed.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: Paul Siebert
Keywords: Computer science
Date of Award: 1997
Depositing User: Enlighten Team
Unique ID: glathesis:1997-75221
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 19 Nov 2019 21:43
Last Modified: 19 Nov 2019 21:43

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