REMOTE MONITORING WITH NEAR-INFRARED FIBER OPTICS

Abstract Human calculi of various compositions were automatically identified by using near-infrared excitation Fourier-transform Raman spectrometry. After having built a 150-compound Raman library as a first step, we used a commercial software for infrared spectra (program BIRSY, from Brüker) to determine the composition of different calculi. Good results were obtained for both classical Raman laser and Raman laser fiber optics spectroscopies. With the use of a natural biological medium, e.g., urine, to mimic as closely as possible clinical in vivo conditions, the automatic search correctly identified the calculus composition with relatively good test quality; in some mixtures, however, the results can only be considered semi-quantitative at present, even after smoothing of the spectra.

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Assessing Laser Cleaning of a Limestone Monument by Fiber Optics Reflectance Spectroscopy (FORS) and Visible and Near-Infrared (VNIR) Hyperspectral Imaging (HSI)

Minerals ◽

10.3390/min10121052 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1052

Author(s):

Costanza Cucci ◽

Olga De Pascale ◽

Giorgio S. Senesi

Keyword(s):

Fiber Optics ◽

Hyperspectral Imaging ◽

Near Infrared ◽

Conservation Status ◽

Spectral Characteristics ◽

Imaging Spectroscopy ◽

Reflectance Spectroscopy ◽

Laser Cleaning ◽

Cleaning Process ◽

Invasive Approach

Fiber optics reflectance spectroscopy (FORS) and visible and near-infrared (VNIR) hyperspectral imaging (HSI) were applied to assess and control the laser cleaning process of a deeply darkened limestone surface collected from the historic entrance gate of Castello Svevo, Bari, Italy. Both techniques enabled us to verify the different degree of removal of a thick deposit of black crust from the surface of the walls. Results obtained were in good agreement with those of previous studies of the elemental composition achieved by application of laser-induced breakdown spectroscopy (LIBS). Coupling FORS and VNIR-HSI provided important information on the optimal conditions to evaluate the conservation status and determine the more appropriate level of cleaning restoration, thus avoiding over- and/or under-cleaning. Imaging spectroscopy was used to obtain maps of areas featuring the same or different spectral characteristics, so to achieve a sufficient removal of unwanted layers, without modifying the surface underneath, and to increase the efficiency of traditional cleaning techniques. The performance of the combined non-invasive approach used in this work shows promise for further applications to other types of rocks and highlights the potential for in situ assessment of the laser cleaning process based on reflectance spectroscopy.

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Performance and Selected Applications of an Acousto-Optic Tunable Filter Near-Infrared Spectrometer

Applied Spectroscopy ◽

10.1366/0003702953963823 ◽

1995 ◽

Vol 49 (2) ◽

pp. 177-180 ◽

Cited By ~ 14

Author(s):

Martin Hühne ◽

Ursula Eschenauer ◽

Heinz W. Siesler

Keyword(s):

Aqueous Solution ◽

Fiber Optics ◽

Near Infrared ◽

Tunable Filter ◽

Near Ir ◽

Infrared Spectrometer ◽

And Performance ◽

Contact Free ◽

Near Infrared Spectrometer

The design and applications of a near-infrared (near-IR) spectrometer with an acousto-optic tunable filter (AOTF) as monochromator and light fiber optics are described. The aim of this spectrometer is rapid product and reaction control via remote sensing and chemometric data evaluation. Its application and performance are illustrated by the determination of the water content of acetone and by the contact-free temperature measurement of an aqueous solution.

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