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dc.contributor.advisorHurtado, Johnen_US
dc.creatorGesting, Peter Paulen_US
dc.date.accessioned2006-04-12T16:04:11Z
dc.date.available2006-04-12T16:04:11Z
dc.date.created2005-12en_US
dc.date.issued2006-04-12
dc.identifier.urihttp://hdl.handle.net/1969.1/3191
dc.description.abstractDue to the Columbia Space Shuttle Accident of February 2003, the Columbia Accident Investigation Board determined the need for an on-orbit inspection system for the Thermal Protection System that accurately determines damage depth to 0.25". NASA contracted the Spacecraft Technology Center in College Station, Texas, for a proof-of-concept photogrammetric system. This system involves a high quality digital camera placed on the International Space Station, capable of taking high fidelity images of the orbiter as it rotates through the Rendezvous Pitch Maneuver. Due to the pitch rotation, the images are tilted at different angles. The tilt causes the damage to exhibit parallax between multiple images. The tilted images are therefore registered to the near-vertical images using visually striking features on the undamaged surface of the Thermal Protection System that appear in multiple images taken at different tilt angles. The images become relatively oriented after registration, and features in one image are ensured to lie on the epipolar line in the other images. Features that do not lie on the undamaged surface, however, are shifted in the tilted images. These pixels are matched to the near-vertical image using a sliding-window area-matching approach. The windows are matched using a least-squares error method. The change in location for a pixel in a tilted image from its expected location on the undamaged surface is called the pixel disparity. This disparity is linearly scaled using the tilt angle and the pixel sampling to determine the depth of the damage at that pixel location. The algorithm is tested on a set of damaged tiles at the Johnson Space Center in Houston and the photogrammetric damage depth is then compared to a set of truth data provided by NASA. The photogrammetric method shows promise, with the 0.25" error limit being exceeded in only a few pixel locations. Once the camera properties are fully known from calibration, this systematic error should be reduced.en_US
dc.format.extent8249116 bytes
dc.format.mediumelectronicen_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherTexas A&M Universityen_US
dc.subjectImage Processingen_US
dc.subjectPhotogrammetryen_US
dc.subjectThermal Protection Systemen_US
dc.titleA photogrammetric on-orbit inspection for orbiter thermal protection systemen_US
dc.typeBooken
dc.typeThesisen
thesis.degree.departmentAerospace Engineeringen_US
thesis.degree.disciplineAerospace Engineeringen_US
thesis.degree.grantorTexas A&M Universityen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelMastersen_US
dc.contributor.committeeMemberJunkins, Johnen_US
dc.contributor.committeeMemberLangari, Rezaen_US
dc.contributor.committeeMemberValasek, Johnen_US
dc.type.genreElectronic Thesisen_US
dc.type.materialtexten_US
dc.format.digitalOriginborn digitalen_US


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