Geometric modelling and calibration of a spherical camera imaging system

dc.contributor.authorLichti, Derek D.
dc.contributor.authorJarron, David
dc.contributor.authorTredoux, Wynand
dc.contributor.authorShahbazi, Mozhdeh M.
dc.contributor.authorRadovanovic, Robert
dc.date.accessioned2020-04-16T20:23:12Z
dc.date.available2020-04-16T20:23:12Z
dc.date.issued2020-04-16
dc.descriptionPoostprint of paper accepted for publication in the Photogrammetric Record on 27/03/2020en_US
dc.description.abstractThe Ladybug5 is an integrated, multi-camera system that features a near-spherical field of view. It is commonly deployed on mobile mapping systems to collect imagery for 3D reality capture. This paper describes an approach for the geometric modelling and self-calibration of this system. The collinearity equations of the pinhole camera model are augmented with five radial lens distortion terms to correct the severe barrel distortion. Weighted relative orientation stability constraints are added to the self-calibrating bundle adjustment solution to enforce the angular and positional stability between the Ladybug5’s six cameras. Results are presented from two calibration data-sets and an independent data-set for accuracy assessment. It is demonstrated that centimetre-level 3D reconstruction accuracy can be achieved with the proposed approach. Moreover, the effectiveness of the lens distortion modelling is demonstrated. Image-space precision and object-space accuracy are improved by 92% and 93%, respectively, relative to a two-term model. The high correlations between lens distortion coefficients were not found to be detrimental to the solution. The mechanical stability of the system was assessed by comparing calibrations taken before and after ten months of routine camera system use. The results suggest sub-pixel interior orientation stability and millimetre-level relative orientation stability. Analyses of accuracy and parameter correlation demonstrate that a slightly-relaxed weighting strategy is preferred to tightly-enforced relative orientation stability constraints.en_US
dc.description.grantingagencyNatural Sciences and Engineering Research Council (NSERC)en_US
dc.identifier.citationLichti, D. D., Jarron, D., Tredoux, W., Shabazi, M. M., & Radovanovic, R. (2020). Geometric modelling and calibration of a spherical camera imaging system. "Photogrammetric Record".en_US
dc.identifier.grantnumberCRDPJ 505367 - 16en_US
dc.identifier.urihttp://hdl.handle.net/1880/111805
dc.identifier.urihttps://dx.doi.org/10.11575/PRISM/37684
dc.publisher.departmentGeomatics Engineeringen_US
dc.publisher.facultySchulich School of Engineeringen_US
dc.publisher.hasversionacceptedVersionen_US
dc.publisher.institutionUniversity of Calgaryen_US
dc.publisher.institutionUniversity of Calgaryen_US
dc.rightsUnless otherwise indicated, this material is protected by copyright and has been made available with authorization from the copyright owner. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.en_US
dc.titleGeometric modelling and calibration of a spherical camera imaging systemen_US
dc.typejournal articleen_US
ucalgary.item.requestcopytrueen_US
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