Data fusion from multiple sources for the production of orthographic and perspective views with automatic visibility checking

dc.contributor.author	Γραμματικόπουλος, Λάζαρος	el
dc.contributor.author	Καλησπεράκης, Ηλίας	el
dc.contributor.author	Καρράς, Γιώργος	el
dc.contributor.author	Πέτσα, Έλλη	el
dc.date.accessioned	2015-03-17T09:14:11Z
dc.date.available	2015-03-17T09:14:11Z
dc.date.issued	2015-03-17
dc.identifier.uri	http://hdl.handle.net/11400/8075
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ηνωμένες Πολιτείες	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/us/	*
dc.source	http://geocenter.survey.ntua.gr/main/labs/photo/staff/gkarras/Karras_Cipa_2005a.pdf	el
dc.subject	Automation
dc.subject	Visualization
dc.subject	Orthorectification
dc.subject	Ορθοαναγωγή
dc.subject	DEM/DTM
dc.subject	Laser scanning
dc.subject	Σάρωση laser
dc.subject	Αυτοματοποίηση
dc.subject	Οραματισμός
dc.title	Data fusion from multiple sources for the production of orthographic and perspective views with automatic visibility checking	en
heal.type	conferenceItem
heal.classification	Topography
heal.classification	Geodesy
heal.classification	Τοπογραφία
heal.classification	Γεωδαισία
heal.classificationURI	http://skos.um.es/unescothes/C04078
heal.classificationURI	http://id.loc.gov/authorities/subjects/sh85053969
heal.classificationURI	N/A-Τοπογραφία
heal.classificationURI	N/A-Γεωδαισία
heal.keywordURI	http://skos.um.es/unescothes/C00313
heal.keywordURI	http://id.loc.gov/authorities/subjects/sh85143939
heal.language	en
heal.access	free
heal.recordProvider	Τεχνολογικό Εκπαιδευτικό Ίδρυμα Αθήνας. Σχολή Τεχνολογικών Εφαρμογών.Τμήμα Τοπογραφίας	el
heal.bibliographicCitation	Grammatikopoulos, L., Kalisperakis, I., Karras, G. and Petsa, E. [χ.χ]. Data fusion from multiple sources for the production of orthographic and perspective views with automatic visibility checking. Proc. XX CIPA International Symposium, Torino, 27 September - 1 October, pp. 819-824.	en
heal.abstract	Orthophotography – and photo-textured 3D surface models, in general – are most important photogrammetric products in heritage conservation. However, it is now common knowledge that conventional orthorectification software accepts only surface descriptions obtained via 2D triangulation and cannot handle the question of image visibility. Ignoring multiple surface elevations and image occlusions of the complex surface shapes, typically met in conservation tasks, results in products visually and geometrically distorted. Tiresome human intervention in the surface modeling and image orthorectification stages might partly remedy this shortcoming. For surface modeling, however, laser scanners allow now collection of numerous accurate surface points and creation of 3D meshes. The authors present their approach for an automated production of correct orthoimages (and perspective views), given a multiple image coverage with known calibration/orientation data and fully 3D surface representations derived through laser scanning. The developed algorithm initially detects surface occlusions in the direction of projection. Next, all available imagery is utilised to establish a colour value for each pixel of the new image. After back-projecting (using the bundle adjustment data) all surface triangles onto all initial images to establish visibilities, texture ‘blending’ is performed. Suitable weighting controls the local radiometric contribution of each participating source image, while outlying colour values (due mainly to registration and modeling errors) are automatically filtered with a simple statistical test. The generation of a depth map for each original image provides a means to further restrict the effects of orientation and modeling errors on texturing, mainly by checking closeness to occlusion borders. This ‘topological’ information may also allow establishing suitable image windows for colour interpolation. Practical tests of the implemented algorithm, using images with multiple overlap and two 3D models, indicate that this fusion of laser scanner and photogrammetry is indeed capable to automatically synthesize novel views from multiple images. The developed approach, combining an outcome of geometric accuracy and visual quality with speed, appears as a realistic approach in heritage conservation. Further necessary elaborations are also outlined.	el
heal.fullTextAvailability	false
heal.conferenceName	Proc. XX CIPA International Symposium	el
heal.conferenceItemType	full paper