Fig 6 - uploaded by Thomas Calligaro
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a RIS end-members map distribution obtained using the Spectral Angle Mapper (SAM) algorithm. b Endmembers spectra from the RIS datacube. The chosen angle tolerances are the following, from up to bottom: 1: 0.45, 2: 0.110, 3: 0.097, 4: 0.045, 5: 0.05, 6: 0.135
Source publication
Photoluminescence (PL) under monochromatic illumination in the UV-Vis-NIR (200–1000 nm), and Reflectance Imaging Spectroscopy (RIS) in the visible and near-infrared domain (NIR, 700–1000 nm) are well-established techniques which usefully complements X-ray fluorescence spectrometry (XRF) in the study of paintworks. PL under UV illumination allows th...
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Context 1
... been reduced to 768 corresponding to the 400-1000 nm spectral range. To improve the signal-to-noise ratio, a Savitzky-Golay smoothing has been applied, with a 10 nm filter width. The dataset was processed with ENVI 5.3 software by selecting relevant endmembers and mapping them by Spectral Angle Mapper algorithm. The resulting map is presented in Fig. 6a, along with the corresponding endmembers, in Fig. 6b. The identification of the endmembers is presented in Table 1. ...
Context 2
... spectral range. To improve the signal-to-noise ratio, a Savitzky-Golay smoothing has been applied, with a 10 nm filter width. The dataset was processed with ENVI 5.3 software by selecting relevant endmembers and mapping them by Spectral Angle Mapper algorithm. The resulting map is presented in Fig. 6a, along with the corresponding endmembers, in Fig. 6b. The identification of the endmembers is presented in Table 1. ...
Citations
... For this reason, the correlation of the collected data by both techniques is essential for obtaining a comprehensive and holistic view of the objects under investigation. By combining the advantages of each mentioned modality, researchers and art conservators can achieve a more accurate, precise, and insightful analysis method [14][15][16][17]. Two distinct approaches characterize the trend toward multimodal analysis. ...
... Two distinct approaches characterize the trend toward multimodal analysis. The first approach involves using multiple techniques within a unified system to generate inherently co-registered and synchronized data cubes [16,17]. The second approach involves using distinct systems for asynchronous imaging measurements and the subsequent data co-registration and data fusion [14,15]. ...
Scanning micrο X-ray fluorescence (μ-XRF) and multispectral imaging (MSI) were applied to study philately stamps, selected for their small size and intricate structures. The μ-XRF measurements were accomplished using the M6 Jetstream Bruker scanner under optimized conditions for spatial resolution, while the MSI measurements were performed employing the XpeCAM-X02 camera. The datasets were acquired asynchronously. Elemental distribution maps can be extracted from the μ-XRF dataset, while chemical distribution maps can be obtained from the analysis of the multispectral dataset. The objective of the present work is the fusion of the datasets from the two spectral imaging modalities. An algorithmic co-registration of the two datasets is applied as a first step, aiming to align the multispectral and μ-XRF images and to adapt to the pixel sizes, as small as a few tens of micrometers. The dataset fusion is accomplished by applying k-means clustering of the multispectral dataset, attributing a representative spectrum to each pixel, and defining the multispectral clusters. Subsequently, the μ-XRF dataset within a specific multispectral cluster is analyzed by evaluating the mean XRF spectrum and performing k-means sub-clustering of the μ-XRF dataset, allowing the differentiation of areas with variable elemental composition within the multispectral cluster. The data fusion approach proves its validity and strength in the context of philately stamps. We demonstrate that the fusion of two spectral imaging modalities enhances their analytical capabilities significantly. The spectral analysis of pixels within clusters can provide more information than analyzing the same pixels as part of the entire dataset.
... Portable X-ray Fluorescence spectroscopy has proved to be valuable for in situ identification of the elemental composition of the pigments and a guide for further investigations with complementary analytical techniques. (Colantonio 2021, Moreau et al. 2023 This method is noninvasive, multi-elemental, fast and low cost (compared with other elemental techniques such as PIXE). ...
This review covers advances in the analysis of advanced materials, metals, fuels and lubricants, nanostructures, ceramics, refractories, organic and inorganic chemicals, catalysts and nuclear materials by a range of techniques including X-ray, ICP, LIBS, mass spectrometry, synchrotron-based techniques, plus non-destructive and ablation surface techniques.
This review covers developments in and applications of XRF techniques such as EDXRF, WDXRF, TXRF, XRF microscopy using technologies such as synchrotron sources, X-ray optics, X-ray tubes and detectors in laboratory, mobile and hand-held systems.
Scanning x-ray fluorescence (MA-XRF), Reflectance Imaging Spectroscopy (RIS) and Luminescence Imaging Spectroscopy (LIS) are scientific methods extensively used in the investigation of artworks in Cultural Heritage Science. Nevertheless, these three highly complementary imaging methods have never been implemented in a single instrument. In this paper, we present a scanning system that is the first to simultaneously combine MA-XRF, RIS, and LIS techniques, generating spatially aligned hyperspectral datasets. The specifications of the instrument and of the collected datacubes are described, together with the processing pipeline developed for the coupled exploitation and interpretation. The operation of this instrument, combining XRF with RIS and LIS mapping in an extended range (400-2500 nm and 200-1000 nm, respectively), is exemplified on an anonymous test painting, studied previously. A focus on a restored area of this painting allows to illustrates the complementarity of the three aforementioned methods, for the visualization and characterization of pigments, varnish, and binders.
