The representation of colour and more in general optic behaviour of 3D digital assets has always been a complex matter, of primary importance especially when representing the descriptive features of archaeological and architectural heritage. This topic involves different research fields, different ranging technologies (active and passive sensors) and different professional skills. In fact, time consuming techniques or expensive devices are not suitable for budgets and abilities that in general cannot be found in the field of documentation of Cultural Heritage. For this reason low-cost and rapid solution are in general most welcome, rather than sophisticated techniques that lead to reliable physical BRDF acquisition, with the disadvantage of being actually still very far from a true implementation in small or intermediate research projects, as well as in case of extensive documentation of archaeological areas. The general purpose of this paper is the explanation of a pipeline aimed at converting apparent colour texture into diffuse maps starting from the output provided by Structure from Motion application, taking account of some case studies from historic centre of Ravenna. A set of different materials, characterized by different optical behaviours, ranging from Lambertian surfaces to some dielectric specular materials have been surveyed using different devices (active and passive sensors) and then mapped with a set of different textures obtained from apparent colour. The workflow consists in a double data capture: on the one hand geometric aspects of archaeological remains (laser scanner and passive sensors for SfM applications), on the other hand a surveying of environmental illumination using HDR images. This technique, developed in the frame of CGI and visual effects creation, is based on an extensive use of render-to-texture solutions (baking) implemented inside entertainment applications, whose function is to store indirect illumination solution from HDRI into (u,v) texturing system. This greyscale image provides an effective masking solution for a set of apparent colour textures of the same object resulting from different radiometric recovery. Logistic aspects of the photographic campaign, frames pre-processing and texture post-processing form part of a pipeline aimed at converting apparent colour texture into a set of images able to generate a more natural and photo-realistic representation of 3D assets, since the typical “double shadow” effect from SfM generated models results mitigated.

A novel method for shadow removal and BRDF simulation of texture from SfM applications / Cipriani, Luca; Fantini, Filippo; Bertacchi, Silvia. - ELETTRONICO. - (2015), pp. 246-247. (Intervento presentato al convegno CAA 2015 - 43rd Computer Applications and Quantitative Methods in Archaeology tenutosi a Siena nel 30 marzo - 3 Aprile 2015).

A novel method for shadow removal and BRDF simulation of texture from SfM applications

CIPRIANI, LUCA;FANTINI, FILIPPO;BERTACCHI, SILVIA
2015

Abstract

The representation of colour and more in general optic behaviour of 3D digital assets has always been a complex matter, of primary importance especially when representing the descriptive features of archaeological and architectural heritage. This topic involves different research fields, different ranging technologies (active and passive sensors) and different professional skills. In fact, time consuming techniques or expensive devices are not suitable for budgets and abilities that in general cannot be found in the field of documentation of Cultural Heritage. For this reason low-cost and rapid solution are in general most welcome, rather than sophisticated techniques that lead to reliable physical BRDF acquisition, with the disadvantage of being actually still very far from a true implementation in small or intermediate research projects, as well as in case of extensive documentation of archaeological areas. The general purpose of this paper is the explanation of a pipeline aimed at converting apparent colour texture into diffuse maps starting from the output provided by Structure from Motion application, taking account of some case studies from historic centre of Ravenna. A set of different materials, characterized by different optical behaviours, ranging from Lambertian surfaces to some dielectric specular materials have been surveyed using different devices (active and passive sensors) and then mapped with a set of different textures obtained from apparent colour. The workflow consists in a double data capture: on the one hand geometric aspects of archaeological remains (laser scanner and passive sensors for SfM applications), on the other hand a surveying of environmental illumination using HDR images. This technique, developed in the frame of CGI and visual effects creation, is based on an extensive use of render-to-texture solutions (baking) implemented inside entertainment applications, whose function is to store indirect illumination solution from HDRI into (u,v) texturing system. This greyscale image provides an effective masking solution for a set of apparent colour textures of the same object resulting from different radiometric recovery. Logistic aspects of the photographic campaign, frames pre-processing and texture post-processing form part of a pipeline aimed at converting apparent colour texture into a set of images able to generate a more natural and photo-realistic representation of 3D assets, since the typical “double shadow” effect from SfM generated models results mitigated.
2015
CAA 2015 - 43rd Computer Applications and Quantitative Methods in Archaeology
246
247
A novel method for shadow removal and BRDF simulation of texture from SfM applications / Cipriani, Luca; Fantini, Filippo; Bertacchi, Silvia. - ELETTRONICO. - (2015), pp. 246-247. (Intervento presentato al convegno CAA 2015 - 43rd Computer Applications and Quantitative Methods in Archaeology tenutosi a Siena nel 30 marzo - 3 Aprile 2015).
Cipriani, Luca; Fantini, Filippo; Bertacchi, Silvia
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/555726
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