ACQUISITION AND REPRODUCTION OF SURFACE APPEARANCE IN ARCHITECTURAL ORTHOIMAGES

Software tools for photogrametric and multi-view stereo reconstruction are nowadays of generalized use in the digitization of architectural cultural heritage. Together with laser scanners, these are well established methods to digitize the three-dimensional geometric properties of real objects. Howe...

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Main Authors: A. Martos, R. Cachero
Format: Article
Language:English
Published: Copernicus Publications 2015-02-01
Series:The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Online Access:http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XL-5-W4/139/2015/isprsarchives-XL-5-W4-139-2015.pdf
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author A. Martos
R. Cachero
author_facet A. Martos
R. Cachero
author_sort A. Martos
collection DOAJ
description Software tools for photogrametric and multi-view stereo reconstruction are nowadays of generalized use in the digitization of architectural cultural heritage. Together with laser scanners, these are well established methods to digitize the three-dimensional geometric properties of real objects. However, the acquired photographic colour mapping of the resulting point clouds or the textured mesh cannot differentiate the proper surface appearance from the influence of the particular illumination present at the moment of the digitization. Acquisition of the actual <i>surface appearance</i>, separated from the existing illumination, is still a challenge for any kind of cultural heritage item, but very specially for architectural elements. Methods based on systematic sampling with commuting light patterns in a laboratory set-up are not suitable. Immovable and outdoor items are normally limited to the existing and uncontrolled natural illumination. <br><br> This paper demonstrates a practical methodology for appearance acquisition, previously introduced in (Martos and Ruiz, 2013), applied here specifically for the production of re-illuminable architectural orthoimages. It is suitable for outdoor environments, where the illumination is variable and uncontrolled. In fact, naturally occurring changes in light among different images along the day are actually desired and exploited, producing an enhanced multi-layer dynamic texture that is not limited to a frozen RGB colour map. These layers contain valuable complementary information about the depth of the geometry, surface normal fine details and other illuminationdependent parameters, such as direct and indirect light and projected self-shadows, allowing an enhanced and re-illuminable ortoimage representation.
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spelling doaj.art-e47304549c034df9a2479ae4a53c8caf2022-12-22T00:24:29ZengCopernicus PublicationsThe International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences1682-17502194-90342015-02-01XL-5/W413914610.5194/isprsarchives-XL-5-W4-139-2015ACQUISITION AND REPRODUCTION OF SURFACE APPEARANCE IN ARCHITECTURAL ORTHOIMAGESA. Martos0R. CacheroDogram, Parque Tecnológico de Asturias, 33428 Llanera, SpainSoftware tools for photogrametric and multi-view stereo reconstruction are nowadays of generalized use in the digitization of architectural cultural heritage. Together with laser scanners, these are well established methods to digitize the three-dimensional geometric properties of real objects. However, the acquired photographic colour mapping of the resulting point clouds or the textured mesh cannot differentiate the proper surface appearance from the influence of the particular illumination present at the moment of the digitization. Acquisition of the actual <i>surface appearance</i>, separated from the existing illumination, is still a challenge for any kind of cultural heritage item, but very specially for architectural elements. Methods based on systematic sampling with commuting light patterns in a laboratory set-up are not suitable. Immovable and outdoor items are normally limited to the existing and uncontrolled natural illumination. <br><br> This paper demonstrates a practical methodology for appearance acquisition, previously introduced in (Martos and Ruiz, 2013), applied here specifically for the production of re-illuminable architectural orthoimages. It is suitable for outdoor environments, where the illumination is variable and uncontrolled. In fact, naturally occurring changes in light among different images along the day are actually desired and exploited, producing an enhanced multi-layer dynamic texture that is not limited to a frozen RGB colour map. These layers contain valuable complementary information about the depth of the geometry, surface normal fine details and other illuminationdependent parameters, such as direct and indirect light and projected self-shadows, allowing an enhanced and re-illuminable ortoimage representation.http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XL-5-W4/139/2015/isprsarchives-XL-5-W4-139-2015.pdf
spellingShingle A. Martos
R. Cachero
ACQUISITION AND REPRODUCTION OF SURFACE APPEARANCE IN ARCHITECTURAL ORTHOIMAGES
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
title ACQUISITION AND REPRODUCTION OF SURFACE APPEARANCE IN ARCHITECTURAL ORTHOIMAGES
title_full ACQUISITION AND REPRODUCTION OF SURFACE APPEARANCE IN ARCHITECTURAL ORTHOIMAGES
title_fullStr ACQUISITION AND REPRODUCTION OF SURFACE APPEARANCE IN ARCHITECTURAL ORTHOIMAGES
title_full_unstemmed ACQUISITION AND REPRODUCTION OF SURFACE APPEARANCE IN ARCHITECTURAL ORTHOIMAGES
title_short ACQUISITION AND REPRODUCTION OF SURFACE APPEARANCE IN ARCHITECTURAL ORTHOIMAGES
title_sort acquisition and reproduction of surface appearance in architectural orthoimages
url http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XL-5-W4/139/2015/isprsarchives-XL-5-W4-139-2015.pdf
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