Near light correction for image relighting and 3D shape recovery

Huang, Xiang; Walton, Marc; Bearman, Greg; Cossairt, Oliver

doi:10.1109/digitalheritage.2015.7413874

Cited by 13 publications

(13 citation statements)

References 21 publications

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“…Several authors have introduced photometric stereo models that utilize a nearlight rather than a far-light model (Huang et al, 2016;Logothetis et al, 2016;Xie, Dai and Wang, 2015). If the energy of the light is considered in a far-light model -to account for light fall off -the intensity at each pixel can be described by Equation 2.13.…”

Section: Other Photometric Stereo Approachesmentioning

confidence: 99%

“…The near light model in Huang et al, 2016 uses a more complicated approach that accounts for the larger fall off that occurs from closely positioned lights (Equation 2.14). The near-light model can overcome some of the warping of the shape that is caused by the far-light assumption (Huang et al, 2016).…”

Section: Other Photometric Stereo Approachesmentioning

confidence: 99%

“…The lighting directions of the relighting dome were calibrated using the method described in chapter 5 -using a reflective sphere and the RTIBuilder software Cultural Heritage Imaging, 2015. The near-light photometric stereo algorithm from Huang et al, 2016 was modified so that it accepts .lp files, the pixel size of the camera, and the camera to surface distance; it used that information to calculate the absolute light positions (in pixels) from the surface. Once the light positions were calibrated, the modified algorithm was used to run a batch process on all 24 photometric stereo tiles.…”

Section: Photometric Stereomentioning

confidence: 99%

“…The comparison of the far-light and near-light photometric stereo models on a woodblock created by Paul Gauguin. (Huang et al, 2016) 44 the data significantly reduces the error from both methods. (Nehab et al, 2005) 49 Huang et al, 2016.…”

mentioning

confidence: 99%

“…(Huang et al, 2016) 44 the data significantly reduces the error from both methods. (Nehab et al, 2005) 49 Huang et al, 2016. It can be seen in the calibration target that there is still a low-frequency warping in the data -the base should be flat.…”

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The Geometric Documentation of Painted Surfaces

Dhanda¹

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Section: Other Photometric Stereo Approachesmentioning

confidence: 99%

Section: Other Photometric Stereo Approachesmentioning

confidence: 99%

Section: Photometric Stereomentioning

confidence: 99%

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confidence: 99%

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The Geometric Documentation of Painted Surfaces

Dhanda¹

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Photometric Stereo by UV-Induced Fluorescence to Detect Protrusions on Georgia O’Keeffe’s Paintings

et al. 2019

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A significant number of oil paintings produced by Georgia O' Keeffe (1887Keeffe ( -1986 show surface protrusions of varying width, up to several hundreds of microns. These protrusions are similar to those described in the art conservation literature as metallic soaps. Since the presence of these protrusions raises questions about the state of conservation and long-term prospects for deterioration of these artworks, a 3D-imaging technique, photometric stereo using ultraviolet illumination, was developed for the long-term monitoring of the surface-shape of the protrusions and the surrounding paint.Because the UV fluorescence response of painting materials is isotropic, errors typically 1 arXiv:1711.08103v1 [cs.GR] 22 Nov 2017 caused by non-Lambertian (anisotropic) specularities when using visible reflected light can be avoided providing a more accurate estimation of shape. As an added benefit, fluorescence provides additional contrast information contributing to materials characterization. The developed methodology aims to detect, characterize, and quantify the distribution of micro-protrusions and their development over the surface of entire artworks. Combined with a set of analytical in-situ techniques, and computational tools, this approach constitutes a novel methodology to investigate the selective distribution of protrusions in correlation with the composition of painting materials at the macroscale. While focused on O'Keeffe's paintings as a case study, we expect the proposed approach to have broader significance by providing a non-invasive protocol to the conservation community to probe topological changes for any relatively flat painted surface of an artwork, and more specifically to monitor the dynamic formation of protrusions, in relation to paint composition and modifications of environmental conditions, loans, exhibitions and storage over the long-term.

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