title: An explorative chemometric approach applied to hyperspectral images for the study of illuminated manuscripts.
abstract: Hyperspectral imaging (HSI) is a fast non-invasive imaging technology recently applied in the field of art conservation. With the help of chemometrics, important information about the spectral properties and spatial distribution of pigments can be extracted from HSI data. With the intent of expanding the applications of chemometrics to the interpretation of hyperspectral images of historical documents, and, at the same time, to study the colorants and their spatial distribution on ancient illuminated manuscripts, an explorative chemometric approach is here presented. The method makes use of chemometric tools for spectral de-noising (minimum noise fraction (MNF)) and image analysis (multivariate image analysis (MIA) and iterative key set factor analysis (IKSFA)/spectral angle mapper (SAM)) which have given an efficient separation, classification and mapping of colorants from visible-near-infrared (VNIR) hyperspectral images of an ancient illuminated fragment. The identification of colorants was achieved by extracting and interpreting the VNIR spectra as well as by using a portable X-ray fluorescence (XRF) spectrometer.
authors.affiliation: Department of Chemistry, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway. Electronic address: emilio.catelli@ntnu.no.
authors.forename: Emilio
authors.initials: E
authors.lastname: Catelli
authors.affiliation: Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
authors.forename: Lise Lyngsnes
authors.initials: LL
authors.lastname: Randeberg
authors.affiliation: Department of Chemistry, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
authors.forename: Bjørn Kåre
authors.initials: BK
authors.lastname: Alsberg
authors.affiliation: Department of Chemistry, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
authors.forename: Kidane Fanta
authors.initials: KF
authors.lastname: Gebremariam
authors.affiliation: Catholic Diocese of Fano, Italy.
authors.forename: Silvano
authors.initials: S
authors.lastname: Bracci
keywords: Chemometrics; Colorants; Illuminated manuscripts; VNIR hyperspectral imaging