Low-Cost Multispectral System Design for Pigment Analysis in Works of Art.

Tania Kleynhans,David W Messinger,John K Delaney,Roger L Easton

doi:10.3390/s21155138

Tania Kleynhans, David W Messinger + Show 2 more

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https://doi.org/10.3390/s21155138

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Abstract

To better understand and preserve works of art, knowledge is needed about the pigments used to create the artwork. Various noninvasive techniques have been used previously to create pigment maps, such as combining X-ray fluorescence and hyperspectral imaging data. Unfortunately, most museums have limited funding for the expense of specialized research equipment, such as hyperspectral reflectance imaging systems. However, many museums have hand-held point X-ray fluorescence systems attached to motorized easels for scanning artwork. To assist museums in acquiring data that can produce similar results to that of HSI systems, while minimizing equipment costs, this study designed and modeled a prototype system to demonstrate the expected performance of a low-cost multispectral system that can be attached to existing motorized easels. We show that multispectral systems with a well-chosen set of spectral bands can often produce classification maps with value on par with hyperspectral systems. This study analyzed the potential for capturing data with a point scanning system through predefined filters. By applying the system and noise modeling parameters to HSI data captured from a 14th-Century illumination, the study reveals that the proposed multispectral imaging system is a viable option for this need.

Highlights

Since conservation scientists are not interested in a pixel-by-pixel ground truth, but instead, in general pigment maps that specify the locations of the pigments or mixtures, the results were compared visually and not statistically
The aim of this study was to design a low-cost solution for museums that already have motorized X-ray fluorescence (XRF) scanning easels such that the proposed multispectral imaging system can be attached for simultaneous image capture
Since macroscale XRF imaging already takes a significant amount of time, collecting reflectance data concurrently with XRF frees up time for the conservation scientists, as well as limits the time the object is kept in the lab

Summary

Introduction

To make informed decisions about conservation methods for specific works of art, conservation scientists require knowledge about the artwork that includes (but is not limited to) which pigments and binders were used to create the painting, the substrate, and information about any varnish or previous in-painting. Scholars use this information to learn more about the artist and working methods of the time. To identify the pigments used in an artwork, various noninvasive imaging methods and algorithms have been developed in recent years. The combination of using X-ray fluorescence (XRF) and reflectance hyperspectral imaging (HSI) data has proven very successful in this domain [1,2]

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