Multispectral imaging system using 12 interference filters for mapping pigments

Abstract

Multispectral imaging systems are used in art examination in order to map pigments and binders as well as retouches. This work presents a simple system composed of a monochromatic CCD camera and a set of only 12 interference filters characterized by different bandwidths and spacing throughout the covered electromagnetic spectrum (400-805 nm). The reasoning supporting the selection of these specific filters is discussed, as well as the results obtained on a collection of 54 historical pigments and on a series of 18 th century frescoes in Sicily. Generally, the filters set for similar systems are chosen equally spaced across the recorded spectrum. For this study the centre wavelength and the bandwidth of these filters have been chosen accordingly to the spectral features of historical pigments. This system allows only for a qualitative reconstruction of pigments reflectance spectra. It must be considered a valuable tool for segmenting the images of polychrome artworks and to identify areas of interest for further analytical examinations if more conclusive results are necessary. ResumoOs sistemas multiespectrais de imagem são utilizados na análise de obras de arte para mapear e identificar pigmentos e aglutinantes, bem como reintegrações cromáticas. Este trabalho apresenta um sistema simples composto por uma câmara CCD monocromática e um conjunto de apenas 12 filtros de interferência caracterizados por diferente espaçamento e largura das bandas ao longo do espectro electromagnético (400-805 nm). É justificada a selecção destes filtros e são discutidos os resultados obtidos quer com um conjunto de 54 pigmentos históricos quer com algumas pinturas a fresco, do século XVIII, da Sicília. De uma forma geral, os filtros usados em sistemas semelhantes são espaçados ao longo do espectro, mas, neste estudo, o comprimento de onda central e a largura da banda dos filtros foram seleccionados de modo a melhorar a representação das características espectrais dos pigmentos históricos. Este sistema permite apenas a reconstituição qualitativa dos espectros de reflectância. Deve ser considerado um instrumento útil para a segmentação de imagens de obras de arte polícromas e identificação de áreas de interesse para exame analítico mais detalhado se forem necessários resultados mais conclusivos. Article / Artigo

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A Digital Reconstruction of a Historical Building and Virtual Reintegration of Mural Paintings to Create an Interactive and Immersive Experience in Virtual Reality

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3d Modeling for Rock Art Documentation Using Lightweight Multispectral Camera

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