A software assistant for manual stereo photometrology
| dc.contributor.author | Sheer, Paul | |
| dc.date.accessioned | 2017-04-28T10:51:19Z | |
| dc.date.available | 2017-04-28T10:51:19Z | |
| dc.date.issued | 1997 | |
| dc.description | A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of master of Science in Engineering. | en_ZA |
| dc.description.abstract | A software package was written under the X Window System, Version 11, to assist in manual stereopsis of multiple views. The package enables multiple high resolution (2000 by 1500 pixels and higher) black and white photographs to be viewed simultaneously. Images have adjustable zoom windows which can be manipulated with the pointing device. The zoom windows enlarge to many times the resolution of the image enabling sub-pixel measurements to be extrapolated by the operator. A user-friendly interface allows for fast pinhole camera calibration (from known 3D calibration points) and enables three dimensional lines, circles, grids, cylinders and planes to be fitted to markers specified by the user. These geometric objects are automatically rendered in 3D for comparison with the images. The camera calibration is performed using an iterative optimisation algorithm which also tries multiple combinations of omitted calibration points. This allows for some fault tolerance of the algorithm with respect to erroneous calibration points. Vector mathematics for the geometrical fits is derived. The calibration is shown to converge on a variety of photographs from actual plant surveys. In an artificial test on an array of constructed 3D coordinate markers, absolute accuracy was found to be 1 mm (standard deviation of the Euclidean error) for a distance of 2.5 meters from a standard 35 mm camera. This translates to an error of 1.6 pixels in the scanned views. Lens distortion was assumed to be negligible, except for aspect ratio distortion which was calibrated for. Finally. to demonstrate the efficacy of the package, a 3D model was reconstructed from ten photographs of a human face, taken from different angles. | en_ZA |
| dc.description.librarian | AC2017 | en_ZA |
| dc.format.extent | Online resource (144 leaves) | |
| dc.identifier.citation | Sheer, Paul (1997) A software assistant for manual stereo photometrology, University of the Witwatersrand, Johannesburg, <http://wiredspace.wits.ac.za/handle/10539/22434> | |
| dc.identifier.uri | http://hdl.handle.net/10539/22434 | |
| dc.language.iso | en | en_ZA |
| dc.subject | Aerial photogrammetry -- data processing | en_ZA |
| dc.subject | X window system (computer system) | en_ZA |
| dc.title | A software assistant for manual stereo photometrology | en_ZA |
| dc.type | Thesis | en_ZA |