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Products for grant PR-258900-18

PR-258900-18
Metal Soap Protrusions on Georgia O'Keeffe's Paintings: Establishing a New Quantitative Imaging Paradigm for Linking Scientif
Marc Walton, Northwestern University

Grant details: https://securegrants.neh.gov/publicquery/main.aspx?f=1&gn=PR-258900-18

Hand-guided qualitative deflectometry with a mobile device (Article)
Title: Hand-guided qualitative deflectometry with a mobile device
Author: Florian Willomitzer, Chia-Kai Yeh, Vikas Gupta, William Spies, Florian Schiffers, Aggelos Katsaggelo
Abstract: We introduce a system that exploits the screen and front-facing camera of a mobile device to perform three-dimensional deflectometry-based surface measurements. In contrast to current mobile deflectometry systems, our method can capture surfaces with large normal variation and wide field of view (FoV). We achieve this by applying automated multi-view panoramic stitching algorithms to produce a large FoV normal map from a hand-guided capture process without the need for external tracking systems, like robot arms or fiducials. The presented work enables 3D surface measurements of specular objects ’in the wild’ with a system accessible to users with little to no technical imaging experience. We demonstrate high-quality 3D surface measurements without the need for a calibration procedure.
Year: 2020
Format: Journal
Publisher: Optics Express

GhostScan (Computer Program)
Title: GhostScan
Author: Marc Walton
Author: Merlin Nau
Author: Florian Willomitzer
Author: Ollie Cossairt
Author: Aggelos Katsaggelos
Abstract: This open source platform aims at uniting the knowledge of different three-dimensional imaging and projection techniques, including their calibration, image processing and visualization. Our goal is to have all modules in one place, such that the use of different cameras, projectors, calibration techniques or image processing algorithms can be done in a straight forward manner. The classes Camera, Projection, Calibration and ImageProcessing serve as the base classes and contain the basic functions and parameters, which are shared by any object and are ought to be overwritten in the corresponding subclass. This also means that any user can create classes for their own specific cameras, projectors, etc. using their own libraries, while enabling a smooth integration. Regarding the cablibration, capturing and computation of the imaging system, additional base classes, namely CalibrationSession and CaptureSession, are established from which different 3D imaging techniques inherit functions and parameters. Last but not least a simple visualization class is provided to show the images using the matplotlib and others to visualize images, normal maps, arrow maps, point clouds and meshes. The class structure is visualized in the image below.
Year: 2021
Primary URL: http://github.com/NU-ACCESS/GhostScan
Primary URL Description: GitHub code repository
Access Model: open access
Programming Language/Platform: Python
Source Available?: Yes

The influence of commercial primed canvases in the manifestation of metal soaps protrusions in Georgia O’Keeffe’s oil paintings (Article)
Title: The influence of commercial primed canvases in the manifestation of metal soaps protrusions in Georgia O’Keeffe’s oil paintings
Author: Annette S. Ortiz Miranda
Author: Dale Kronkright
Author: Marc Walton
Abstract: During a routine condition survey in 2007 at the Georgia O’Keeffe Museum in Santa Fe, micro-protrusions were found scattered across the surfaces of the artist’s oil paintings produced between 1920 and 1950. In many of her works, including Pedernal (1941) and A Man from the Desert (1941), lead soaps were found aggregated at the painting surface, forcing the surrounding paint to deform into pin-sized protrusions. The structure and composition of the protrusions was analyzed to determine why they formed. Microsamples were removed from four of O’Keeffe’s paintings and investigated using a combination of SEM–EDX, GC–MS, and FT-IR. The combined GC–MS and FT-IR results indicate that the protrusions contain primarily lead carboxylates. The results obtained for a series of ground samples removed from four different paintings were then compared with samples collected from a commercially pre-primed canvas roll found in the artist’s house in Ghost Ranch, NM. We identified two different types of canvases: i) a commercially pre-primed canvas and ii) artist primed canvas. This commercially pre-primed canvas roll has a similar morphology to the ground layers in her paintings that contain protrusions additionally these grounds were found to contain an excess of free fatty acids and metal carboxylates (lead soaps) based on a comparison to canvases the artist primed herself. Based on the analytical results from the four paintings and the commercial pre-primed canvas, we concluded that the artist’s use of this particular commercially pre-primed canvas between 1920 and 1950 play an important role in the observed micro-protrusions.
Year: 2020
Primary URL: https://heritagesciencejournal.springeropen.com/articles/10.1186/s40494-020-00451-7#citeas
Primary URL Description: Journal website
Access Model: open access
Format: Journal
Periodical Title: Heritage Science
Publisher: Springer Nature

Method and system for three-dimensional surface measurement with a mobile device (Equipment)
Name: Method and system for three-dimensional surface measurement with a mobile device
Description: U.S. Patent Application 16/937,045. A three-dimensional (3D) imaging system includes a mobile device that has a display screen configured to display a series of patterns onto an object that is to be imaged. The mobile device also includes a front-facing camera configured to capture reflections of the series of patterns off of the object. The system also includes a controller that is configured to control a timing of the series of patterns that appear on the display screen and activation of the front-facing camera in relation to the appearance of the series of patterns.
Location: Northwestern University
Year: 2021

SkinScan: Low-Cost 3D-Scanning for Dermatologic Diagnosis and Documentation (Article)
Title: SkinScan: Low-Cost 3D-Scanning for Dermatologic Diagnosis and Documentation
Author: Merlin A Nau
Author: Florian Schiffers
Author: Yunhao Li
Author: Andreas Maier
Author: Jack Tumblin
Author: Marc Walton
Author: Aggelos K Katsaggelos
Author: Florian Willomitzer
Author: Oliver Cossairt
Abstract: The utilization of computational photography becomes increasingly essential in the medical field. Today, imaging techniques for dermatology range from two-dimensional (2D) color imagery with a mobile device to professional clinical imaging systems measuring additional detailed three-dimensional (3D) data. The latter are commonly expensive and not accessible to a broad audience. In this work, we propose a novel system and software framework that relies only on low-cost (and even mobile) commodity devices present in every household to measure detailed 3D information of the human skin with a 3D-gradient-illumination-based method. We believe that our system has great potential for early-stage diagnosis and monitoring of skin diseases, especially in vastly populated or underdeveloped areas.
Year: 2021
Primary URL: https://arxiv.org/abs/2102.00508
Access Model: open access
Format: Journal
Periodical Title: arXiv preprint arXiv:2102.00508
Publisher: ICIP Conference 2021

Photometric Stereo by UV-Induced Fluorescence to Detect Protrusions on Georgia O’Keeffe’s Paintings (Article)
Title: Photometric Stereo by UV-Induced Fluorescence to Detect Protrusions on Georgia O’Keeffe’s Paintings
Author: Johanna Salvant
Author: Marc Walton
Author: Dale Kronkright
Author: Chia-Kai Yeh
Author: Fengqiang Li
Author: Oliver Cossairt
Abstract: A significant number of oil paintings produced by Georgia O’Keeffe (1887–1986) 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 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 material 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.
Year: 2019
Primary URL: https://link.springer.com/chapter/10.1007/978-3-319-90617-1_22
Access Model: subscription only
Format: Journal
Periodical Title: Part of the Cultural Heritage Science book series (CUHESC)
Publisher: Springer

Clearing Up The ‘Art Acne’ On Georgia O’Keeffe’s Paintings (Radio/Audio Broadcast or Recording)
Title: Clearing Up The ‘Art Acne’ On Georgia O’Keeffe’s Paintings
Writer: Ira Flato
Director: Alex Lim
Producer: Alexa Lim
Abstract: The painter Georgia O’Keeffe is known for her bold paintings of landscapes and flowers. When talking about those famous flowers, she said: “Nobody sees a flower–really–it is so small–we haven’t time–and to see takes time like to have a friend takes time.” She took her small observations and filled her canvas with bright colors and close-ups, so those flowers couldn’t be missed. Recently, scientists took a closer look at those paintings and noticed smaller details that O’Keeffe did not intend to include. They found “art acne”—small pock marks—on many of her paintings caused by age and reactions of the pigments. Marc Walton, co-director of the Center for Scientific Studies in the Arts at Northwestern University and Art Institute of Chicago, talks about the chemistry behind the “art acne,” and how these paintings might be conserved in the future.
Date: 02/22/2019
Primary URL: https://www.sciencefriday.com/segments/clearing-up-the-art-acne-on-georgia-okeeffes-paintings/
Primary URL Description: NPR radio program Science Friday
Access Model: open access
Format: Radio


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